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src/share/classes/com/sun/tools/javac/code/Types.java@96d4226bdd60
src/share/classes/com/sun/tools/javac/code/Types.java
Mon, 07 Feb 2011 18:10:13 +0000
- author
- mcimadamore
- date
- Mon, 07 Feb 2011 18:10:13 +0000
- changeset 858
- 96d4226bdd60
- parent 846
- 17bafae67e9d
- child 877
- 351027202f60
- permissions
- -rw-r--r--
7007615: java_util/generics/phase2/NameClashTest02 fails since jdk7/pit/b123.
Summary: override clash algorithm is not implemented correctly
Reviewed-by: jjg
1 /*
2 * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
26 package com.sun.tools.javac.code;
28 import java.lang.ref.SoftReference;
29 import java.util.*;
31 import com.sun.tools.javac.util.*;
32 import com.sun.tools.javac.util.List;
34 import com.sun.tools.javac.jvm.ClassReader;
35 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
36 import com.sun.tools.javac.code.Lint.LintCategory;
37 import com.sun.tools.javac.comp.Check;
39 import static com.sun.tools.javac.code.Scope.*;
40 import static com.sun.tools.javac.code.Type.*;
41 import static com.sun.tools.javac.code.TypeTags.*;
42 import static com.sun.tools.javac.code.Symbol.*;
43 import static com.sun.tools.javac.code.Flags.*;
44 import static com.sun.tools.javac.code.BoundKind.*;
45 import static com.sun.tools.javac.util.ListBuffer.lb;
47 /**
48 * Utility class containing various operations on types.
49 *
50 * <p>Unless other names are more illustrative, the following naming
51 * conventions should be observed in this file:
52 *
53 * <dl>
54 * <dt>t</dt>
55 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
56 * <dt>s</dt>
57 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
58 * <dt>ts</dt>
59 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
60 * <dt>ss</dt>
61 * <dd>A second list of types should be named ss.</dd>
62 * </dl>
63 *
64 * <p><b>This is NOT part of any supported API.
65 * If you write code that depends on this, you do so at your own risk.
66 * This code and its internal interfaces are subject to change or
67 * deletion without notice.</b>
68 */
69 public class Types {
70 protected static final Context.Key<Types> typesKey =
71 new Context.Key<Types>();
73 final Symtab syms;
74 final JavacMessages messages;
75 final Names names;
76 final boolean allowBoxing;
77 final ClassReader reader;
78 final Source source;
79 final Check chk;
80 List<Warner> warnStack = List.nil();
81 final Name capturedName;
83 // <editor-fold defaultstate="collapsed" desc="Instantiating">
84 public static Types instance(Context context) {
85 Types instance = context.get(typesKey);
86 if (instance == null)
87 instance = new Types(context);
88 return instance;
89 }
91 protected Types(Context context) {
92 context.put(typesKey, this);
93 syms = Symtab.instance(context);
94 names = Names.instance(context);
95 allowBoxing = Source.instance(context).allowBoxing();
96 reader = ClassReader.instance(context);
97 source = Source.instance(context);
98 chk = Check.instance(context);
99 capturedName = names.fromString("<captured wildcard>");
100 messages = JavacMessages.instance(context);
101 }
102 // </editor-fold>
104 // <editor-fold defaultstate="collapsed" desc="upperBound">
105 /**
106 * The "rvalue conversion".<br>
107 * The upper bound of most types is the type
108 * itself. Wildcards, on the other hand have upper
109 * and lower bounds.
110 * @param t a type
111 * @return the upper bound of the given type
112 */
113 public Type upperBound(Type t) {
114 return upperBound.visit(t);
115 }
116 // where
117 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
119 @Override
120 public Type visitWildcardType(WildcardType t, Void ignored) {
121 if (t.isSuperBound())
122 return t.bound == null ? syms.objectType : t.bound.bound;
123 else
124 return visit(t.type);
125 }
127 @Override
128 public Type visitCapturedType(CapturedType t, Void ignored) {
129 return visit(t.bound);
130 }
131 };
132 // </editor-fold>
134 // <editor-fold defaultstate="collapsed" desc="lowerBound">
135 /**
136 * The "lvalue conversion".<br>
137 * The lower bound of most types is the type
138 * itself. Wildcards, on the other hand have upper
139 * and lower bounds.
140 * @param t a type
141 * @return the lower bound of the given type
142 */
143 public Type lowerBound(Type t) {
144 return lowerBound.visit(t);
145 }
146 // where
147 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
149 @Override
150 public Type visitWildcardType(WildcardType t, Void ignored) {
151 return t.isExtendsBound() ? syms.botType : visit(t.type);
152 }
154 @Override
155 public Type visitCapturedType(CapturedType t, Void ignored) {
156 return visit(t.getLowerBound());
157 }
158 };
159 // </editor-fold>
161 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
162 /**
163 * Checks that all the arguments to a class are unbounded
164 * wildcards or something else that doesn't make any restrictions
165 * on the arguments. If a class isUnbounded, a raw super- or
166 * subclass can be cast to it without a warning.
167 * @param t a type
168 * @return true iff the given type is unbounded or raw
169 */
170 public boolean isUnbounded(Type t) {
171 return isUnbounded.visit(t);
172 }
173 // where
174 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
176 public Boolean visitType(Type t, Void ignored) {
177 return true;
178 }
180 @Override
181 public Boolean visitClassType(ClassType t, Void ignored) {
182 List<Type> parms = t.tsym.type.allparams();
183 List<Type> args = t.allparams();
184 while (parms.nonEmpty()) {
185 WildcardType unb = new WildcardType(syms.objectType,
186 BoundKind.UNBOUND,
187 syms.boundClass,
188 (TypeVar)parms.head);
189 if (!containsType(args.head, unb))
190 return false;
191 parms = parms.tail;
192 args = args.tail;
193 }
194 return true;
195 }
196 };
197 // </editor-fold>
199 // <editor-fold defaultstate="collapsed" desc="asSub">
200 /**
201 * Return the least specific subtype of t that starts with symbol
202 * sym. If none exists, return null. The least specific subtype
203 * is determined as follows:
204 *
205 * <p>If there is exactly one parameterized instance of sym that is a
206 * subtype of t, that parameterized instance is returned.<br>
207 * Otherwise, if the plain type or raw type `sym' is a subtype of
208 * type t, the type `sym' itself is returned. Otherwise, null is
209 * returned.
210 */
211 public Type asSub(Type t, Symbol sym) {
212 return asSub.visit(t, sym);
213 }
214 // where
215 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
217 public Type visitType(Type t, Symbol sym) {
218 return null;
219 }
221 @Override
222 public Type visitClassType(ClassType t, Symbol sym) {
223 if (t.tsym == sym)
224 return t;
225 Type base = asSuper(sym.type, t.tsym);
226 if (base == null)
227 return null;
228 ListBuffer<Type> from = new ListBuffer<Type>();
229 ListBuffer<Type> to = new ListBuffer<Type>();
230 try {
231 adapt(base, t, from, to);
232 } catch (AdaptFailure ex) {
233 return null;
234 }
235 Type res = subst(sym.type, from.toList(), to.toList());
236 if (!isSubtype(res, t))
237 return null;
238 ListBuffer<Type> openVars = new ListBuffer<Type>();
239 for (List<Type> l = sym.type.allparams();
240 l.nonEmpty(); l = l.tail)
241 if (res.contains(l.head) && !t.contains(l.head))
242 openVars.append(l.head);
243 if (openVars.nonEmpty()) {
244 if (t.isRaw()) {
245 // The subtype of a raw type is raw
246 res = erasure(res);
247 } else {
248 // Unbound type arguments default to ?
249 List<Type> opens = openVars.toList();
250 ListBuffer<Type> qs = new ListBuffer<Type>();
251 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
252 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head));
253 }
254 res = subst(res, opens, qs.toList());
255 }
256 }
257 return res;
258 }
260 @Override
261 public Type visitErrorType(ErrorType t, Symbol sym) {
262 return t;
263 }
264 };
265 // </editor-fold>
267 // <editor-fold defaultstate="collapsed" desc="isConvertible">
268 /**
269 * Is t a subtype of or convertiable via boxing/unboxing
270 * convertions to s?
271 */
272 public boolean isConvertible(Type t, Type s, Warner warn) {
273 boolean tPrimitive = t.isPrimitive();
274 boolean sPrimitive = s.isPrimitive();
275 if (tPrimitive == sPrimitive) {
276 checkUnsafeVarargsConversion(t, s, warn);
277 return isSubtypeUnchecked(t, s, warn);
278 }
279 if (!allowBoxing) return false;
280 return tPrimitive
281 ? isSubtype(boxedClass(t).type, s)
282 : isSubtype(unboxedType(t), s);
283 }
284 //where
285 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
286 if (t.tag != ARRAY || isReifiable(t)) return;
287 ArrayType from = (ArrayType)t;
288 boolean shouldWarn = false;
289 switch (s.tag) {
290 case ARRAY:
291 ArrayType to = (ArrayType)s;
292 shouldWarn = from.isVarargs() &&
293 !to.isVarargs() &&
294 !isReifiable(from);
295 break;
296 case CLASS:
297 shouldWarn = from.isVarargs() &&
298 isSubtype(from, s);
299 break;
300 }
301 if (shouldWarn) {
302 warn.warn(LintCategory.VARARGS);
303 }
304 }
306 /**
307 * Is t a subtype of or convertiable via boxing/unboxing
308 * convertions to s?
309 */
310 public boolean isConvertible(Type t, Type s) {
311 return isConvertible(t, s, Warner.noWarnings);
312 }
313 // </editor-fold>
315 // <editor-fold defaultstate="collapsed" desc="isSubtype">
316 /**
317 * Is t an unchecked subtype of s?
318 */
319 public boolean isSubtypeUnchecked(Type t, Type s) {
320 return isSubtypeUnchecked(t, s, Warner.noWarnings);
321 }
322 /**
323 * Is t an unchecked subtype of s?
324 */
325 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
326 if (t.tag == ARRAY && s.tag == ARRAY) {
327 if (((ArrayType)t).elemtype.tag <= lastBaseTag) {
328 return isSameType(elemtype(t), elemtype(s));
329 } else {
330 ArrayType from = (ArrayType)t;
331 ArrayType to = (ArrayType)s;
332 if (from.isVarargs() &&
333 !to.isVarargs() &&
334 !isReifiable(from)) {
335 warn.warn(LintCategory.VARARGS);
336 }
337 return isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
338 }
339 } else if (isSubtype(t, s)) {
340 return true;
341 }
342 else if (t.tag == TYPEVAR) {
343 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
344 }
345 else if (s.tag == UNDETVAR) {
346 UndetVar uv = (UndetVar)s;
347 if (uv.inst != null)
348 return isSubtypeUnchecked(t, uv.inst, warn);
349 }
350 else if (!s.isRaw()) {
351 Type t2 = asSuper(t, s.tsym);
352 if (t2 != null && t2.isRaw()) {
353 if (isReifiable(s))
354 warn.silentWarn(LintCategory.UNCHECKED);
355 else
356 warn.warn(LintCategory.UNCHECKED);
357 return true;
358 }
359 }
360 return false;
361 }
363 /**
364 * Is t a subtype of s?<br>
365 * (not defined for Method and ForAll types)
366 */
367 final public boolean isSubtype(Type t, Type s) {
368 return isSubtype(t, s, true);
369 }
370 final public boolean isSubtypeNoCapture(Type t, Type s) {
371 return isSubtype(t, s, false);
372 }
373 public boolean isSubtype(Type t, Type s, boolean capture) {
374 if (t == s)
375 return true;
377 if (s.tag >= firstPartialTag)
378 return isSuperType(s, t);
380 if (s.isCompound()) {
381 for (Type s2 : interfaces(s).prepend(supertype(s))) {
382 if (!isSubtype(t, s2, capture))
383 return false;
384 }
385 return true;
386 }
388 Type lower = lowerBound(s);
389 if (s != lower)
390 return isSubtype(capture ? capture(t) : t, lower, false);
392 return isSubtype.visit(capture ? capture(t) : t, s);
393 }
394 // where
395 private TypeRelation isSubtype = new TypeRelation()
396 {
397 public Boolean visitType(Type t, Type s) {
398 switch (t.tag) {
399 case BYTE: case CHAR:
400 return (t.tag == s.tag ||
401 t.tag + 2 <= s.tag && s.tag <= DOUBLE);
402 case SHORT: case INT: case LONG: case FLOAT: case DOUBLE:
403 return t.tag <= s.tag && s.tag <= DOUBLE;
404 case BOOLEAN: case VOID:
405 return t.tag == s.tag;
406 case TYPEVAR:
407 return isSubtypeNoCapture(t.getUpperBound(), s);
408 case BOT:
409 return
410 s.tag == BOT || s.tag == CLASS ||
411 s.tag == ARRAY || s.tag == TYPEVAR;
412 case NONE:
413 return false;
414 default:
415 throw new AssertionError("isSubtype " + t.tag);
416 }
417 }
419 private Set<TypePair> cache = new HashSet<TypePair>();
421 private boolean containsTypeRecursive(Type t, Type s) {
422 TypePair pair = new TypePair(t, s);
423 if (cache.add(pair)) {
424 try {
425 return containsType(t.getTypeArguments(),
426 s.getTypeArguments());
427 } finally {
428 cache.remove(pair);
429 }
430 } else {
431 return containsType(t.getTypeArguments(),
432 rewriteSupers(s).getTypeArguments());
433 }
434 }
436 private Type rewriteSupers(Type t) {
437 if (!t.isParameterized())
438 return t;
439 ListBuffer<Type> from = lb();
440 ListBuffer<Type> to = lb();
441 adaptSelf(t, from, to);
442 if (from.isEmpty())
443 return t;
444 ListBuffer<Type> rewrite = lb();
445 boolean changed = false;
446 for (Type orig : to.toList()) {
447 Type s = rewriteSupers(orig);
448 if (s.isSuperBound() && !s.isExtendsBound()) {
449 s = new WildcardType(syms.objectType,
450 BoundKind.UNBOUND,
451 syms.boundClass);
452 changed = true;
453 } else if (s != orig) {
454 s = new WildcardType(upperBound(s),
455 BoundKind.EXTENDS,
456 syms.boundClass);
457 changed = true;
458 }
459 rewrite.append(s);
460 }
461 if (changed)
462 return subst(t.tsym.type, from.toList(), rewrite.toList());
463 else
464 return t;
465 }
467 @Override
468 public Boolean visitClassType(ClassType t, Type s) {
469 Type sup = asSuper(t, s.tsym);
470 return sup != null
471 && sup.tsym == s.tsym
472 // You're not allowed to write
473 // Vector<Object> vec = new Vector<String>();
474 // But with wildcards you can write
475 // Vector<? extends Object> vec = new Vector<String>();
476 // which means that subtype checking must be done
477 // here instead of same-type checking (via containsType).
478 && (!s.isParameterized() || containsTypeRecursive(s, sup))
479 && isSubtypeNoCapture(sup.getEnclosingType(),
480 s.getEnclosingType());
481 }
483 @Override
484 public Boolean visitArrayType(ArrayType t, Type s) {
485 if (s.tag == ARRAY) {
486 if (t.elemtype.tag <= lastBaseTag)
487 return isSameType(t.elemtype, elemtype(s));
488 else
489 return isSubtypeNoCapture(t.elemtype, elemtype(s));
490 }
492 if (s.tag == CLASS) {
493 Name sname = s.tsym.getQualifiedName();
494 return sname == names.java_lang_Object
495 || sname == names.java_lang_Cloneable
496 || sname == names.java_io_Serializable;
497 }
499 return false;
500 }
502 @Override
503 public Boolean visitUndetVar(UndetVar t, Type s) {
504 //todo: test against origin needed? or replace with substitution?
505 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
506 return true;
508 if (t.inst != null)
509 return isSubtypeNoCapture(t.inst, s); // TODO: ", warn"?
511 t.hibounds = t.hibounds.prepend(s);
512 return true;
513 }
515 @Override
516 public Boolean visitErrorType(ErrorType t, Type s) {
517 return true;
518 }
519 };
521 /**
522 * Is t a subtype of every type in given list `ts'?<br>
523 * (not defined for Method and ForAll types)<br>
524 * Allows unchecked conversions.
525 */
526 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
527 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
528 if (!isSubtypeUnchecked(t, l.head, warn))
529 return false;
530 return true;
531 }
533 /**
534 * Are corresponding elements of ts subtypes of ss? If lists are
535 * of different length, return false.
536 */
537 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
538 while (ts.tail != null && ss.tail != null
539 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
540 isSubtype(ts.head, ss.head)) {
541 ts = ts.tail;
542 ss = ss.tail;
543 }
544 return ts.tail == null && ss.tail == null;
545 /*inlined: ts.isEmpty() && ss.isEmpty();*/
546 }
548 /**
549 * Are corresponding elements of ts subtypes of ss, allowing
550 * unchecked conversions? If lists are of different length,
551 * return false.
552 **/
553 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
554 while (ts.tail != null && ss.tail != null
555 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
556 isSubtypeUnchecked(ts.head, ss.head, warn)) {
557 ts = ts.tail;
558 ss = ss.tail;
559 }
560 return ts.tail == null && ss.tail == null;
561 /*inlined: ts.isEmpty() && ss.isEmpty();*/
562 }
563 // </editor-fold>
565 // <editor-fold defaultstate="collapsed" desc="isSuperType">
566 /**
567 * Is t a supertype of s?
568 */
569 public boolean isSuperType(Type t, Type s) {
570 switch (t.tag) {
571 case ERROR:
572 return true;
573 case UNDETVAR: {
574 UndetVar undet = (UndetVar)t;
575 if (t == s ||
576 undet.qtype == s ||
577 s.tag == ERROR ||
578 s.tag == BOT) return true;
579 if (undet.inst != null)
580 return isSubtype(s, undet.inst);
581 undet.lobounds = undet.lobounds.prepend(s);
582 return true;
583 }
584 default:
585 return isSubtype(s, t);
586 }
587 }
588 // </editor-fold>
590 // <editor-fold defaultstate="collapsed" desc="isSameType">
591 /**
592 * Are corresponding elements of the lists the same type? If
593 * lists are of different length, return false.
594 */
595 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
596 while (ts.tail != null && ss.tail != null
597 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
598 isSameType(ts.head, ss.head)) {
599 ts = ts.tail;
600 ss = ss.tail;
601 }
602 return ts.tail == null && ss.tail == null;
603 /*inlined: ts.isEmpty() && ss.isEmpty();*/
604 }
606 /**
607 * Is t the same type as s?
608 */
609 public boolean isSameType(Type t, Type s) {
610 return isSameType.visit(t, s);
611 }
612 // where
613 private TypeRelation isSameType = new TypeRelation() {
615 public Boolean visitType(Type t, Type s) {
616 if (t == s)
617 return true;
619 if (s.tag >= firstPartialTag)
620 return visit(s, t);
622 switch (t.tag) {
623 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
624 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
625 return t.tag == s.tag;
626 case TYPEVAR: {
627 if (s.tag == TYPEVAR) {
628 //type-substitution does not preserve type-var types
629 //check that type var symbols and bounds are indeed the same
630 return t.tsym == s.tsym &&
631 visit(t.getUpperBound(), s.getUpperBound());
632 }
633 else {
634 //special case for s == ? super X, where upper(s) = u
635 //check that u == t, where u has been set by Type.withTypeVar
636 return s.isSuperBound() &&
637 !s.isExtendsBound() &&
638 visit(t, upperBound(s));
639 }
640 }
641 default:
642 throw new AssertionError("isSameType " + t.tag);
643 }
644 }
646 @Override
647 public Boolean visitWildcardType(WildcardType t, Type s) {
648 if (s.tag >= firstPartialTag)
649 return visit(s, t);
650 else
651 return false;
652 }
654 @Override
655 public Boolean visitClassType(ClassType t, Type s) {
656 if (t == s)
657 return true;
659 if (s.tag >= firstPartialTag)
660 return visit(s, t);
662 if (s.isSuperBound() && !s.isExtendsBound())
663 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
665 if (t.isCompound() && s.isCompound()) {
666 if (!visit(supertype(t), supertype(s)))
667 return false;
669 HashSet<SingletonType> set = new HashSet<SingletonType>();
670 for (Type x : interfaces(t))
671 set.add(new SingletonType(x));
672 for (Type x : interfaces(s)) {
673 if (!set.remove(new SingletonType(x)))
674 return false;
675 }
676 return (set.isEmpty());
677 }
678 return t.tsym == s.tsym
679 && visit(t.getEnclosingType(), s.getEnclosingType())
680 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
681 }
683 @Override
684 public Boolean visitArrayType(ArrayType t, Type s) {
685 if (t == s)
686 return true;
688 if (s.tag >= firstPartialTag)
689 return visit(s, t);
691 return s.tag == ARRAY
692 && containsTypeEquivalent(t.elemtype, elemtype(s));
693 }
695 @Override
696 public Boolean visitMethodType(MethodType t, Type s) {
697 // isSameType for methods does not take thrown
698 // exceptions into account!
699 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
700 }
702 @Override
703 public Boolean visitPackageType(PackageType t, Type s) {
704 return t == s;
705 }
707 @Override
708 public Boolean visitForAll(ForAll t, Type s) {
709 if (s.tag != FORALL)
710 return false;
712 ForAll forAll = (ForAll)s;
713 return hasSameBounds(t, forAll)
714 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
715 }
717 @Override
718 public Boolean visitUndetVar(UndetVar t, Type s) {
719 if (s.tag == WILDCARD)
720 // FIXME, this might be leftovers from before capture conversion
721 return false;
723 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
724 return true;
726 if (t.inst != null)
727 return visit(t.inst, s);
729 t.inst = fromUnknownFun.apply(s);
730 for (List<Type> l = t.lobounds; l.nonEmpty(); l = l.tail) {
731 if (!isSubtype(l.head, t.inst))
732 return false;
733 }
734 for (List<Type> l = t.hibounds; l.nonEmpty(); l = l.tail) {
735 if (!isSubtype(t.inst, l.head))
736 return false;
737 }
738 return true;
739 }
741 @Override
742 public Boolean visitErrorType(ErrorType t, Type s) {
743 return true;
744 }
745 };
746 // </editor-fold>
748 // <editor-fold defaultstate="collapsed" desc="fromUnknownFun">
749 /**
750 * A mapping that turns all unknown types in this type to fresh
751 * unknown variables.
752 */
753 public Mapping fromUnknownFun = new Mapping("fromUnknownFun") {
754 public Type apply(Type t) {
755 if (t.tag == UNKNOWN) return new UndetVar(t);
756 else return t.map(this);
757 }
758 };
759 // </editor-fold>
761 // <editor-fold defaultstate="collapsed" desc="Contains Type">
762 public boolean containedBy(Type t, Type s) {
763 switch (t.tag) {
764 case UNDETVAR:
765 if (s.tag == WILDCARD) {
766 UndetVar undetvar = (UndetVar)t;
767 WildcardType wt = (WildcardType)s;
768 switch(wt.kind) {
769 case UNBOUND: //similar to ? extends Object
770 case EXTENDS: {
771 Type bound = upperBound(s);
772 // We should check the new upper bound against any of the
773 // undetvar's lower bounds.
774 for (Type t2 : undetvar.lobounds) {
775 if (!isSubtype(t2, bound))
776 return false;
777 }
778 undetvar.hibounds = undetvar.hibounds.prepend(bound);
779 break;
780 }
781 case SUPER: {
782 Type bound = lowerBound(s);
783 // We should check the new lower bound against any of the
784 // undetvar's lower bounds.
785 for (Type t2 : undetvar.hibounds) {
786 if (!isSubtype(bound, t2))
787 return false;
788 }
789 undetvar.lobounds = undetvar.lobounds.prepend(bound);
790 break;
791 }
792 }
793 return true;
794 } else {
795 return isSameType(t, s);
796 }
797 case ERROR:
798 return true;
799 default:
800 return containsType(s, t);
801 }
802 }
804 boolean containsType(List<Type> ts, List<Type> ss) {
805 while (ts.nonEmpty() && ss.nonEmpty()
806 && containsType(ts.head, ss.head)) {
807 ts = ts.tail;
808 ss = ss.tail;
809 }
810 return ts.isEmpty() && ss.isEmpty();
811 }
813 /**
814 * Check if t contains s.
815 *
816 * <p>T contains S if:
817 *
818 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
819 *
820 * <p>This relation is only used by ClassType.isSubtype(), that
821 * is,
822 *
823 * <p>{@code C<S> <: C<T> if T contains S.}
824 *
825 * <p>Because of F-bounds, this relation can lead to infinite
826 * recursion. Thus we must somehow break that recursion. Notice
827 * that containsType() is only called from ClassType.isSubtype().
828 * Since the arguments have already been checked against their
829 * bounds, we know:
830 *
831 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
832 *
833 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
834 *
835 * @param t a type
836 * @param s a type
837 */
838 public boolean containsType(Type t, Type s) {
839 return containsType.visit(t, s);
840 }
841 // where
842 private TypeRelation containsType = new TypeRelation() {
844 private Type U(Type t) {
845 while (t.tag == WILDCARD) {
846 WildcardType w = (WildcardType)t;
847 if (w.isSuperBound())
848 return w.bound == null ? syms.objectType : w.bound.bound;
849 else
850 t = w.type;
851 }
852 return t;
853 }
855 private Type L(Type t) {
856 while (t.tag == WILDCARD) {
857 WildcardType w = (WildcardType)t;
858 if (w.isExtendsBound())
859 return syms.botType;
860 else
861 t = w.type;
862 }
863 return t;
864 }
866 public Boolean visitType(Type t, Type s) {
867 if (s.tag >= firstPartialTag)
868 return containedBy(s, t);
869 else
870 return isSameType(t, s);
871 }
873 // void debugContainsType(WildcardType t, Type s) {
874 // System.err.println();
875 // System.err.format(" does %s contain %s?%n", t, s);
876 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
877 // upperBound(s), s, t, U(t),
878 // t.isSuperBound()
879 // || isSubtypeNoCapture(upperBound(s), U(t)));
880 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
881 // L(t), t, s, lowerBound(s),
882 // t.isExtendsBound()
883 // || isSubtypeNoCapture(L(t), lowerBound(s)));
884 // System.err.println();
885 // }
887 @Override
888 public Boolean visitWildcardType(WildcardType t, Type s) {
889 if (s.tag >= firstPartialTag)
890 return containedBy(s, t);
891 else {
892 // debugContainsType(t, s);
893 return isSameWildcard(t, s)
894 || isCaptureOf(s, t)
895 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
896 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
897 }
898 }
900 @Override
901 public Boolean visitUndetVar(UndetVar t, Type s) {
902 if (s.tag != WILDCARD)
903 return isSameType(t, s);
904 else
905 return false;
906 }
908 @Override
909 public Boolean visitErrorType(ErrorType t, Type s) {
910 return true;
911 }
912 };
914 public boolean isCaptureOf(Type s, WildcardType t) {
915 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
916 return false;
917 return isSameWildcard(t, ((CapturedType)s).wildcard);
918 }
920 public boolean isSameWildcard(WildcardType t, Type s) {
921 if (s.tag != WILDCARD)
922 return false;
923 WildcardType w = (WildcardType)s;
924 return w.kind == t.kind && w.type == t.type;
925 }
927 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
928 while (ts.nonEmpty() && ss.nonEmpty()
929 && containsTypeEquivalent(ts.head, ss.head)) {
930 ts = ts.tail;
931 ss = ss.tail;
932 }
933 return ts.isEmpty() && ss.isEmpty();
934 }
935 // </editor-fold>
937 // <editor-fold defaultstate="collapsed" desc="isCastable">
938 public boolean isCastable(Type t, Type s) {
939 return isCastable(t, s, Warner.noWarnings);
940 }
942 /**
943 * Is t is castable to s?<br>
944 * s is assumed to be an erased type.<br>
945 * (not defined for Method and ForAll types).
946 */
947 public boolean isCastable(Type t, Type s, Warner warn) {
948 if (t == s)
949 return true;
951 if (t.isPrimitive() != s.isPrimitive())
952 return allowBoxing && (isConvertible(t, s, warn) || isConvertible(s, t, warn));
954 if (warn != warnStack.head) {
955 try {
956 warnStack = warnStack.prepend(warn);
957 checkUnsafeVarargsConversion(t, s, warn);
958 return isCastable.visit(t,s);
959 } finally {
960 warnStack = warnStack.tail;
961 }
962 } else {
963 return isCastable.visit(t,s);
964 }
965 }
966 // where
967 private TypeRelation isCastable = new TypeRelation() {
969 public Boolean visitType(Type t, Type s) {
970 if (s.tag == ERROR)
971 return true;
973 switch (t.tag) {
974 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
975 case DOUBLE:
976 return s.tag <= DOUBLE;
977 case BOOLEAN:
978 return s.tag == BOOLEAN;
979 case VOID:
980 return false;
981 case BOT:
982 return isSubtype(t, s);
983 default:
984 throw new AssertionError();
985 }
986 }
988 @Override
989 public Boolean visitWildcardType(WildcardType t, Type s) {
990 return isCastable(upperBound(t), s, warnStack.head);
991 }
993 @Override
994 public Boolean visitClassType(ClassType t, Type s) {
995 if (s.tag == ERROR || s.tag == BOT)
996 return true;
998 if (s.tag == TYPEVAR) {
999 if (isCastable(t, s.getUpperBound(), Warner.noWarnings)) {
1000 warnStack.head.warn(LintCategory.UNCHECKED);
1001 return true;
1002 } else {
1003 return false;
1004 }
1005 }
1007 if (t.isCompound()) {
1008 Warner oldWarner = warnStack.head;
1009 warnStack.head = Warner.noWarnings;
1010 if (!visit(supertype(t), s))
1011 return false;
1012 for (Type intf : interfaces(t)) {
1013 if (!visit(intf, s))
1014 return false;
1015 }
1016 if (warnStack.head.hasLint(LintCategory.UNCHECKED))
1017 oldWarner.warn(LintCategory.UNCHECKED);
1018 return true;
1019 }
1021 if (s.isCompound()) {
1022 // call recursively to reuse the above code
1023 return visitClassType((ClassType)s, t);
1024 }
1026 if (s.tag == CLASS || s.tag == ARRAY) {
1027 boolean upcast;
1028 if ((upcast = isSubtype(erasure(t), erasure(s)))
1029 || isSubtype(erasure(s), erasure(t))) {
1030 if (!upcast && s.tag == ARRAY) {
1031 if (!isReifiable(s))
1032 warnStack.head.warn(LintCategory.UNCHECKED);
1033 return true;
1034 } else if (s.isRaw()) {
1035 return true;
1036 } else if (t.isRaw()) {
1037 if (!isUnbounded(s))
1038 warnStack.head.warn(LintCategory.UNCHECKED);
1039 return true;
1040 }
1041 // Assume |a| <: |b|
1042 final Type a = upcast ? t : s;
1043 final Type b = upcast ? s : t;
1044 final boolean HIGH = true;
1045 final boolean LOW = false;
1046 final boolean DONT_REWRITE_TYPEVARS = false;
1047 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
1048 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
1049 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
1050 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
1051 Type lowSub = asSub(bLow, aLow.tsym);
1052 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1053 if (highSub == null) {
1054 final boolean REWRITE_TYPEVARS = true;
1055 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
1056 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
1057 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
1058 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
1059 lowSub = asSub(bLow, aLow.tsym);
1060 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
1061 }
1062 if (highSub != null) {
1063 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
1064 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
1065 }
1066 if (!disjointTypes(aHigh.allparams(), highSub.allparams())
1067 && !disjointTypes(aHigh.allparams(), lowSub.allparams())
1068 && !disjointTypes(aLow.allparams(), highSub.allparams())
1069 && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
1070 if (upcast ? giveWarning(a, b) :
1071 giveWarning(b, a))
1072 warnStack.head.warn(LintCategory.UNCHECKED);
1073 return true;
1074 }
1075 }
1076 if (isReifiable(s))
1077 return isSubtypeUnchecked(a, b);
1078 else
1079 return isSubtypeUnchecked(a, b, warnStack.head);
1080 }
1082 // Sidecast
1083 if (s.tag == CLASS) {
1084 if ((s.tsym.flags() & INTERFACE) != 0) {
1085 return ((t.tsym.flags() & FINAL) == 0)
1086 ? sideCast(t, s, warnStack.head)
1087 : sideCastFinal(t, s, warnStack.head);
1088 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1089 return ((s.tsym.flags() & FINAL) == 0)
1090 ? sideCast(t, s, warnStack.head)
1091 : sideCastFinal(t, s, warnStack.head);
1092 } else {
1093 // unrelated class types
1094 return false;
1095 }
1096 }
1097 }
1098 return false;
1099 }
1101 @Override
1102 public Boolean visitArrayType(ArrayType t, Type s) {
1103 switch (s.tag) {
1104 case ERROR:
1105 case BOT:
1106 return true;
1107 case TYPEVAR:
1108 if (isCastable(s, t, Warner.noWarnings)) {
1109 warnStack.head.warn(LintCategory.UNCHECKED);
1110 return true;
1111 } else {
1112 return false;
1113 }
1114 case CLASS:
1115 return isSubtype(t, s);
1116 case ARRAY:
1117 if (elemtype(t).tag <= lastBaseTag ||
1118 elemtype(s).tag <= lastBaseTag) {
1119 return elemtype(t).tag == elemtype(s).tag;
1120 } else {
1121 return visit(elemtype(t), elemtype(s));
1122 }
1123 default:
1124 return false;
1125 }
1126 }
1128 @Override
1129 public Boolean visitTypeVar(TypeVar t, Type s) {
1130 switch (s.tag) {
1131 case ERROR:
1132 case BOT:
1133 return true;
1134 case TYPEVAR:
1135 if (isSubtype(t, s)) {
1136 return true;
1137 } else if (isCastable(t.bound, s, Warner.noWarnings)) {
1138 warnStack.head.warn(LintCategory.UNCHECKED);
1139 return true;
1140 } else {
1141 return false;
1142 }
1143 default:
1144 return isCastable(t.bound, s, warnStack.head);
1145 }
1146 }
1148 @Override
1149 public Boolean visitErrorType(ErrorType t, Type s) {
1150 return true;
1151 }
1152 };
1153 // </editor-fold>
1155 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1156 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1157 while (ts.tail != null && ss.tail != null) {
1158 if (disjointType(ts.head, ss.head)) return true;
1159 ts = ts.tail;
1160 ss = ss.tail;
1161 }
1162 return false;
1163 }
1165 /**
1166 * Two types or wildcards are considered disjoint if it can be
1167 * proven that no type can be contained in both. It is
1168 * conservative in that it is allowed to say that two types are
1169 * not disjoint, even though they actually are.
1170 *
1171 * The type C<X> is castable to C<Y> exactly if X and Y are not
1172 * disjoint.
1173 */
1174 public boolean disjointType(Type t, Type s) {
1175 return disjointType.visit(t, s);
1176 }
1177 // where
1178 private TypeRelation disjointType = new TypeRelation() {
1180 private Set<TypePair> cache = new HashSet<TypePair>();
1182 public Boolean visitType(Type t, Type s) {
1183 if (s.tag == WILDCARD)
1184 return visit(s, t);
1185 else
1186 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1187 }
1189 private boolean isCastableRecursive(Type t, Type s) {
1190 TypePair pair = new TypePair(t, s);
1191 if (cache.add(pair)) {
1192 try {
1193 return Types.this.isCastable(t, s);
1194 } finally {
1195 cache.remove(pair);
1196 }
1197 } else {
1198 return true;
1199 }
1200 }
1202 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1203 TypePair pair = new TypePair(t, s);
1204 if (cache.add(pair)) {
1205 try {
1206 return Types.this.notSoftSubtype(t, s);
1207 } finally {
1208 cache.remove(pair);
1209 }
1210 } else {
1211 return false;
1212 }
1213 }
1215 @Override
1216 public Boolean visitWildcardType(WildcardType t, Type s) {
1217 if (t.isUnbound())
1218 return false;
1220 if (s.tag != WILDCARD) {
1221 if (t.isExtendsBound())
1222 return notSoftSubtypeRecursive(s, t.type);
1223 else // isSuperBound()
1224 return notSoftSubtypeRecursive(t.type, s);
1225 }
1227 if (s.isUnbound())
1228 return false;
1230 if (t.isExtendsBound()) {
1231 if (s.isExtendsBound())
1232 return !isCastableRecursive(t.type, upperBound(s));
1233 else if (s.isSuperBound())
1234 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1235 } else if (t.isSuperBound()) {
1236 if (s.isExtendsBound())
1237 return notSoftSubtypeRecursive(t.type, upperBound(s));
1238 }
1239 return false;
1240 }
1241 };
1242 // </editor-fold>
1244 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1245 /**
1246 * Returns the lower bounds of the formals of a method.
1247 */
1248 public List<Type> lowerBoundArgtypes(Type t) {
1249 return map(t.getParameterTypes(), lowerBoundMapping);
1250 }
1251 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1252 public Type apply(Type t) {
1253 return lowerBound(t);
1254 }
1255 };
1256 // </editor-fold>
1258 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1259 /**
1260 * This relation answers the question: is impossible that
1261 * something of type `t' can be a subtype of `s'? This is
1262 * different from the question "is `t' not a subtype of `s'?"
1263 * when type variables are involved: Integer is not a subtype of T
1264 * where <T extends Number> but it is not true that Integer cannot
1265 * possibly be a subtype of T.
1266 */
1267 public boolean notSoftSubtype(Type t, Type s) {
1268 if (t == s) return false;
1269 if (t.tag == TYPEVAR) {
1270 TypeVar tv = (TypeVar) t;
1271 return !isCastable(tv.bound,
1272 relaxBound(s),
1273 Warner.noWarnings);
1274 }
1275 if (s.tag != WILDCARD)
1276 s = upperBound(s);
1278 return !isSubtype(t, relaxBound(s));
1279 }
1281 private Type relaxBound(Type t) {
1282 if (t.tag == TYPEVAR) {
1283 while (t.tag == TYPEVAR)
1284 t = t.getUpperBound();
1285 t = rewriteQuantifiers(t, true, true);
1286 }
1287 return t;
1288 }
1289 // </editor-fold>
1291 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1292 public boolean isReifiable(Type t) {
1293 return isReifiable.visit(t);
1294 }
1295 // where
1296 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1298 public Boolean visitType(Type t, Void ignored) {
1299 return true;
1300 }
1302 @Override
1303 public Boolean visitClassType(ClassType t, Void ignored) {
1304 if (t.isCompound())
1305 return false;
1306 else {
1307 if (!t.isParameterized())
1308 return true;
1310 for (Type param : t.allparams()) {
1311 if (!param.isUnbound())
1312 return false;
1313 }
1314 return true;
1315 }
1316 }
1318 @Override
1319 public Boolean visitArrayType(ArrayType t, Void ignored) {
1320 return visit(t.elemtype);
1321 }
1323 @Override
1324 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1325 return false;
1326 }
1327 };
1328 // </editor-fold>
1330 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1331 public boolean isArray(Type t) {
1332 while (t.tag == WILDCARD)
1333 t = upperBound(t);
1334 return t.tag == ARRAY;
1335 }
1337 /**
1338 * The element type of an array.
1339 */
1340 public Type elemtype(Type t) {
1341 switch (t.tag) {
1342 case WILDCARD:
1343 return elemtype(upperBound(t));
1344 case ARRAY:
1345 return ((ArrayType)t).elemtype;
1346 case FORALL:
1347 return elemtype(((ForAll)t).qtype);
1348 case ERROR:
1349 return t;
1350 default:
1351 return null;
1352 }
1353 }
1355 public Type elemtypeOrType(Type t) {
1356 Type elemtype = elemtype(t);
1357 return elemtype != null ?
1358 elemtype :
1359 t;
1360 }
1362 /**
1363 * Mapping to take element type of an arraytype
1364 */
1365 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1366 public Type apply(Type t) { return elemtype(t); }
1367 };
1369 /**
1370 * The number of dimensions of an array type.
1371 */
1372 public int dimensions(Type t) {
1373 int result = 0;
1374 while (t.tag == ARRAY) {
1375 result++;
1376 t = elemtype(t);
1377 }
1378 return result;
1379 }
1380 // </editor-fold>
1382 // <editor-fold defaultstate="collapsed" desc="asSuper">
1383 /**
1384 * Return the (most specific) base type of t that starts with the
1385 * given symbol. If none exists, return null.
1386 *
1387 * @param t a type
1388 * @param sym a symbol
1389 */
1390 public Type asSuper(Type t, Symbol sym) {
1391 return asSuper.visit(t, sym);
1392 }
1393 // where
1394 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1396 public Type visitType(Type t, Symbol sym) {
1397 return null;
1398 }
1400 @Override
1401 public Type visitClassType(ClassType t, Symbol sym) {
1402 if (t.tsym == sym)
1403 return t;
1405 Type st = supertype(t);
1406 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1407 Type x = asSuper(st, sym);
1408 if (x != null)
1409 return x;
1410 }
1411 if ((sym.flags() & INTERFACE) != 0) {
1412 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1413 Type x = asSuper(l.head, sym);
1414 if (x != null)
1415 return x;
1416 }
1417 }
1418 return null;
1419 }
1421 @Override
1422 public Type visitArrayType(ArrayType t, Symbol sym) {
1423 return isSubtype(t, sym.type) ? sym.type : null;
1424 }
1426 @Override
1427 public Type visitTypeVar(TypeVar t, Symbol sym) {
1428 if (t.tsym == sym)
1429 return t;
1430 else
1431 return asSuper(t.bound, sym);
1432 }
1434 @Override
1435 public Type visitErrorType(ErrorType t, Symbol sym) {
1436 return t;
1437 }
1438 };
1440 /**
1441 * Return the base type of t or any of its outer types that starts
1442 * with the given symbol. If none exists, return null.
1443 *
1444 * @param t a type
1445 * @param sym a symbol
1446 */
1447 public Type asOuterSuper(Type t, Symbol sym) {
1448 switch (t.tag) {
1449 case CLASS:
1450 do {
1451 Type s = asSuper(t, sym);
1452 if (s != null) return s;
1453 t = t.getEnclosingType();
1454 } while (t.tag == CLASS);
1455 return null;
1456 case ARRAY:
1457 return isSubtype(t, sym.type) ? sym.type : null;
1458 case TYPEVAR:
1459 return asSuper(t, sym);
1460 case ERROR:
1461 return t;
1462 default:
1463 return null;
1464 }
1465 }
1467 /**
1468 * Return the base type of t or any of its enclosing types that
1469 * starts with the given symbol. If none exists, return null.
1470 *
1471 * @param t a type
1472 * @param sym a symbol
1473 */
1474 public Type asEnclosingSuper(Type t, Symbol sym) {
1475 switch (t.tag) {
1476 case CLASS:
1477 do {
1478 Type s = asSuper(t, sym);
1479 if (s != null) return s;
1480 Type outer = t.getEnclosingType();
1481 t = (outer.tag == CLASS) ? outer :
1482 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1483 Type.noType;
1484 } while (t.tag == CLASS);
1485 return null;
1486 case ARRAY:
1487 return isSubtype(t, sym.type) ? sym.type : null;
1488 case TYPEVAR:
1489 return asSuper(t, sym);
1490 case ERROR:
1491 return t;
1492 default:
1493 return null;
1494 }
1495 }
1496 // </editor-fold>
1498 // <editor-fold defaultstate="collapsed" desc="memberType">
1499 /**
1500 * The type of given symbol, seen as a member of t.
1501 *
1502 * @param t a type
1503 * @param sym a symbol
1504 */
1505 public Type memberType(Type t, Symbol sym) {
1506 return (sym.flags() & STATIC) != 0
1507 ? sym.type
1508 : memberType.visit(t, sym);
1509 }
1510 // where
1511 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1513 public Type visitType(Type t, Symbol sym) {
1514 return sym.type;
1515 }
1517 @Override
1518 public Type visitWildcardType(WildcardType t, Symbol sym) {
1519 return memberType(upperBound(t), sym);
1520 }
1522 @Override
1523 public Type visitClassType(ClassType t, Symbol sym) {
1524 Symbol owner = sym.owner;
1525 long flags = sym.flags();
1526 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1527 Type base = asOuterSuper(t, owner);
1528 //if t is an intersection type T = CT & I1 & I2 ... & In
1529 //its supertypes CT, I1, ... In might contain wildcards
1530 //so we need to go through capture conversion
1531 base = t.isCompound() ? capture(base) : base;
1532 if (base != null) {
1533 List<Type> ownerParams = owner.type.allparams();
1534 List<Type> baseParams = base.allparams();
1535 if (ownerParams.nonEmpty()) {
1536 if (baseParams.isEmpty()) {
1537 // then base is a raw type
1538 return erasure(sym.type);
1539 } else {
1540 return subst(sym.type, ownerParams, baseParams);
1541 }
1542 }
1543 }
1544 }
1545 return sym.type;
1546 }
1548 @Override
1549 public Type visitTypeVar(TypeVar t, Symbol sym) {
1550 return memberType(t.bound, sym);
1551 }
1553 @Override
1554 public Type visitErrorType(ErrorType t, Symbol sym) {
1555 return t;
1556 }
1557 };
1558 // </editor-fold>
1560 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1561 public boolean isAssignable(Type t, Type s) {
1562 return isAssignable(t, s, Warner.noWarnings);
1563 }
1565 /**
1566 * Is t assignable to s?<br>
1567 * Equivalent to subtype except for constant values and raw
1568 * types.<br>
1569 * (not defined for Method and ForAll types)
1570 */
1571 public boolean isAssignable(Type t, Type s, Warner warn) {
1572 if (t.tag == ERROR)
1573 return true;
1574 if (t.tag <= INT && t.constValue() != null) {
1575 int value = ((Number)t.constValue()).intValue();
1576 switch (s.tag) {
1577 case BYTE:
1578 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1579 return true;
1580 break;
1581 case CHAR:
1582 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1583 return true;
1584 break;
1585 case SHORT:
1586 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1587 return true;
1588 break;
1589 case INT:
1590 return true;
1591 case CLASS:
1592 switch (unboxedType(s).tag) {
1593 case BYTE:
1594 case CHAR:
1595 case SHORT:
1596 return isAssignable(t, unboxedType(s), warn);
1597 }
1598 break;
1599 }
1600 }
1601 return isConvertible(t, s, warn);
1602 }
1603 // </editor-fold>
1605 // <editor-fold defaultstate="collapsed" desc="erasure">
1606 /**
1607 * The erasure of t {@code |t|} -- the type that results when all
1608 * type parameters in t are deleted.
1609 */
1610 public Type erasure(Type t) {
1611 return erasure(t, false);
1612 }
1613 //where
1614 private Type erasure(Type t, boolean recurse) {
1615 if (t.tag <= lastBaseTag)
1616 return t; /* fast special case */
1617 else
1618 return erasure.visit(t, recurse);
1619 }
1620 // where
1621 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
1622 public Type visitType(Type t, Boolean recurse) {
1623 if (t.tag <= lastBaseTag)
1624 return t; /*fast special case*/
1625 else
1626 return t.map(recurse ? erasureRecFun : erasureFun);
1627 }
1629 @Override
1630 public Type visitWildcardType(WildcardType t, Boolean recurse) {
1631 return erasure(upperBound(t), recurse);
1632 }
1634 @Override
1635 public Type visitClassType(ClassType t, Boolean recurse) {
1636 Type erased = t.tsym.erasure(Types.this);
1637 if (recurse) {
1638 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
1639 }
1640 return erased;
1641 }
1643 @Override
1644 public Type visitTypeVar(TypeVar t, Boolean recurse) {
1645 return erasure(t.bound, recurse);
1646 }
1648 @Override
1649 public Type visitErrorType(ErrorType t, Boolean recurse) {
1650 return t;
1651 }
1652 };
1654 private Mapping erasureFun = new Mapping ("erasure") {
1655 public Type apply(Type t) { return erasure(t); }
1656 };
1658 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
1659 public Type apply(Type t) { return erasureRecursive(t); }
1660 };
1662 public List<Type> erasure(List<Type> ts) {
1663 return Type.map(ts, erasureFun);
1664 }
1666 public Type erasureRecursive(Type t) {
1667 return erasure(t, true);
1668 }
1670 public List<Type> erasureRecursive(List<Type> ts) {
1671 return Type.map(ts, erasureRecFun);
1672 }
1673 // </editor-fold>
1675 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
1676 /**
1677 * Make a compound type from non-empty list of types
1678 *
1679 * @param bounds the types from which the compound type is formed
1680 * @param supertype is objectType if all bounds are interfaces,
1681 * null otherwise.
1682 */
1683 public Type makeCompoundType(List<Type> bounds,
1684 Type supertype) {
1685 ClassSymbol bc =
1686 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
1687 Type.moreInfo
1688 ? names.fromString(bounds.toString())
1689 : names.empty,
1690 syms.noSymbol);
1691 if (bounds.head.tag == TYPEVAR)
1692 // error condition, recover
1693 bc.erasure_field = syms.objectType;
1694 else
1695 bc.erasure_field = erasure(bounds.head);
1696 bc.members_field = new Scope(bc);
1697 ClassType bt = (ClassType)bc.type;
1698 bt.allparams_field = List.nil();
1699 if (supertype != null) {
1700 bt.supertype_field = supertype;
1701 bt.interfaces_field = bounds;
1702 } else {
1703 bt.supertype_field = bounds.head;
1704 bt.interfaces_field = bounds.tail;
1705 }
1706 Assert.check(bt.supertype_field.tsym.completer != null
1707 || !bt.supertype_field.isInterface(),
1708 bt.supertype_field);
1709 return bt;
1710 }
1712 /**
1713 * Same as {@link #makeCompoundType(List,Type)}, except that the
1714 * second parameter is computed directly. Note that this might
1715 * cause a symbol completion. Hence, this version of
1716 * makeCompoundType may not be called during a classfile read.
1717 */
1718 public Type makeCompoundType(List<Type> bounds) {
1719 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1720 supertype(bounds.head) : null;
1721 return makeCompoundType(bounds, supertype);
1722 }
1724 /**
1725 * A convenience wrapper for {@link #makeCompoundType(List)}; the
1726 * arguments are converted to a list and passed to the other
1727 * method. Note that this might cause a symbol completion.
1728 * Hence, this version of makeCompoundType may not be called
1729 * during a classfile read.
1730 */
1731 public Type makeCompoundType(Type bound1, Type bound2) {
1732 return makeCompoundType(List.of(bound1, bound2));
1733 }
1734 // </editor-fold>
1736 // <editor-fold defaultstate="collapsed" desc="supertype">
1737 public Type supertype(Type t) {
1738 return supertype.visit(t);
1739 }
1740 // where
1741 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
1743 public Type visitType(Type t, Void ignored) {
1744 // A note on wildcards: there is no good way to
1745 // determine a supertype for a super bounded wildcard.
1746 return null;
1747 }
1749 @Override
1750 public Type visitClassType(ClassType t, Void ignored) {
1751 if (t.supertype_field == null) {
1752 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
1753 // An interface has no superclass; its supertype is Object.
1754 if (t.isInterface())
1755 supertype = ((ClassType)t.tsym.type).supertype_field;
1756 if (t.supertype_field == null) {
1757 List<Type> actuals = classBound(t).allparams();
1758 List<Type> formals = t.tsym.type.allparams();
1759 if (t.hasErasedSupertypes()) {
1760 t.supertype_field = erasureRecursive(supertype);
1761 } else if (formals.nonEmpty()) {
1762 t.supertype_field = subst(supertype, formals, actuals);
1763 }
1764 else {
1765 t.supertype_field = supertype;
1766 }
1767 }
1768 }
1769 return t.supertype_field;
1770 }
1772 /**
1773 * The supertype is always a class type. If the type
1774 * variable's bounds start with a class type, this is also
1775 * the supertype. Otherwise, the supertype is
1776 * java.lang.Object.
1777 */
1778 @Override
1779 public Type visitTypeVar(TypeVar t, Void ignored) {
1780 if (t.bound.tag == TYPEVAR ||
1781 (!t.bound.isCompound() && !t.bound.isInterface())) {
1782 return t.bound;
1783 } else {
1784 return supertype(t.bound);
1785 }
1786 }
1788 @Override
1789 public Type visitArrayType(ArrayType t, Void ignored) {
1790 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
1791 return arraySuperType();
1792 else
1793 return new ArrayType(supertype(t.elemtype), t.tsym);
1794 }
1796 @Override
1797 public Type visitErrorType(ErrorType t, Void ignored) {
1798 return t;
1799 }
1800 };
1801 // </editor-fold>
1803 // <editor-fold defaultstate="collapsed" desc="interfaces">
1804 /**
1805 * Return the interfaces implemented by this class.
1806 */
1807 public List<Type> interfaces(Type t) {
1808 return interfaces.visit(t);
1809 }
1810 // where
1811 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
1813 public List<Type> visitType(Type t, Void ignored) {
1814 return List.nil();
1815 }
1817 @Override
1818 public List<Type> visitClassType(ClassType t, Void ignored) {
1819 if (t.interfaces_field == null) {
1820 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
1821 if (t.interfaces_field == null) {
1822 // If t.interfaces_field is null, then t must
1823 // be a parameterized type (not to be confused
1824 // with a generic type declaration).
1825 // Terminology:
1826 // Parameterized type: List<String>
1827 // Generic type declaration: class List<E> { ... }
1828 // So t corresponds to List<String> and
1829 // t.tsym.type corresponds to List<E>.
1830 // The reason t must be parameterized type is
1831 // that completion will happen as a side
1832 // effect of calling
1833 // ClassSymbol.getInterfaces. Since
1834 // t.interfaces_field is null after
1835 // completion, we can assume that t is not the
1836 // type of a class/interface declaration.
1837 Assert.check(t != t.tsym.type, t);
1838 List<Type> actuals = t.allparams();
1839 List<Type> formals = t.tsym.type.allparams();
1840 if (t.hasErasedSupertypes()) {
1841 t.interfaces_field = erasureRecursive(interfaces);
1842 } else if (formals.nonEmpty()) {
1843 t.interfaces_field =
1844 upperBounds(subst(interfaces, formals, actuals));
1845 }
1846 else {
1847 t.interfaces_field = interfaces;
1848 }
1849 }
1850 }
1851 return t.interfaces_field;
1852 }
1854 @Override
1855 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
1856 if (t.bound.isCompound())
1857 return interfaces(t.bound);
1859 if (t.bound.isInterface())
1860 return List.of(t.bound);
1862 return List.nil();
1863 }
1864 };
1865 // </editor-fold>
1867 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
1868 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
1870 public boolean isDerivedRaw(Type t) {
1871 Boolean result = isDerivedRawCache.get(t);
1872 if (result == null) {
1873 result = isDerivedRawInternal(t);
1874 isDerivedRawCache.put(t, result);
1875 }
1876 return result;
1877 }
1879 public boolean isDerivedRawInternal(Type t) {
1880 if (t.isErroneous())
1881 return false;
1882 return
1883 t.isRaw() ||
1884 supertype(t) != null && isDerivedRaw(supertype(t)) ||
1885 isDerivedRaw(interfaces(t));
1886 }
1888 public boolean isDerivedRaw(List<Type> ts) {
1889 List<Type> l = ts;
1890 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
1891 return l.nonEmpty();
1892 }
1893 // </editor-fold>
1895 // <editor-fold defaultstate="collapsed" desc="setBounds">
1896 /**
1897 * Set the bounds field of the given type variable to reflect a
1898 * (possibly multiple) list of bounds.
1899 * @param t a type variable
1900 * @param bounds the bounds, must be nonempty
1901 * @param supertype is objectType if all bounds are interfaces,
1902 * null otherwise.
1903 */
1904 public void setBounds(TypeVar t, List<Type> bounds, Type supertype) {
1905 if (bounds.tail.isEmpty())
1906 t.bound = bounds.head;
1907 else
1908 t.bound = makeCompoundType(bounds, supertype);
1909 t.rank_field = -1;
1910 }
1912 /**
1913 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
1914 * third parameter is computed directly, as follows: if all
1915 * all bounds are interface types, the computed supertype is Object,
1916 * otherwise the supertype is simply left null (in this case, the supertype
1917 * is assumed to be the head of the bound list passed as second argument).
1918 * Note that this check might cause a symbol completion. Hence, this version of
1919 * setBounds may not be called during a classfile read.
1920 */
1921 public void setBounds(TypeVar t, List<Type> bounds) {
1922 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1923 syms.objectType : null;
1924 setBounds(t, bounds, supertype);
1925 t.rank_field = -1;
1926 }
1927 // </editor-fold>
1929 // <editor-fold defaultstate="collapsed" desc="getBounds">
1930 /**
1931 * Return list of bounds of the given type variable.
1932 */
1933 public List<Type> getBounds(TypeVar t) {
1934 if (t.bound.isErroneous() || !t.bound.isCompound())
1935 return List.of(t.bound);
1936 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
1937 return interfaces(t).prepend(supertype(t));
1938 else
1939 // No superclass was given in bounds.
1940 // In this case, supertype is Object, erasure is first interface.
1941 return interfaces(t);
1942 }
1943 // </editor-fold>
1945 // <editor-fold defaultstate="collapsed" desc="classBound">
1946 /**
1947 * If the given type is a (possibly selected) type variable,
1948 * return the bounding class of this type, otherwise return the
1949 * type itself.
1950 */
1951 public Type classBound(Type t) {
1952 return classBound.visit(t);
1953 }
1954 // where
1955 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
1957 public Type visitType(Type t, Void ignored) {
1958 return t;
1959 }
1961 @Override
1962 public Type visitClassType(ClassType t, Void ignored) {
1963 Type outer1 = classBound(t.getEnclosingType());
1964 if (outer1 != t.getEnclosingType())
1965 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
1966 else
1967 return t;
1968 }
1970 @Override
1971 public Type visitTypeVar(TypeVar t, Void ignored) {
1972 return classBound(supertype(t));
1973 }
1975 @Override
1976 public Type visitErrorType(ErrorType t, Void ignored) {
1977 return t;
1978 }
1979 };
1980 // </editor-fold>
1982 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
1983 /**
1984 * Returns true iff the first signature is a <em>sub
1985 * signature</em> of the other. This is <b>not</b> an equivalence
1986 * relation.
1987 *
1988 * @see "The Java Language Specification, Third Ed. (8.4.2)."
1989 * @see #overrideEquivalent(Type t, Type s)
1990 * @param t first signature (possibly raw).
1991 * @param s second signature (could be subjected to erasure).
1992 * @return true if t is a sub signature of s.
1993 */
1994 public boolean isSubSignature(Type t, Type s) {
1995 return hasSameArgs(t, s) || hasSameArgs(t, erasure(s));
1996 }
1998 /**
1999 * Returns true iff these signatures are related by <em>override
2000 * equivalence</em>. This is the natural extension of
2001 * isSubSignature to an equivalence relation.
2002 *
2003 * @see "The Java Language Specification, Third Ed. (8.4.2)."
2004 * @see #isSubSignature(Type t, Type s)
2005 * @param t a signature (possible raw, could be subjected to
2006 * erasure).
2007 * @param s a signature (possible raw, could be subjected to
2008 * erasure).
2009 * @return true if either argument is a sub signature of the other.
2010 */
2011 public boolean overrideEquivalent(Type t, Type s) {
2012 return hasSameArgs(t, s) ||
2013 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
2014 }
2016 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
2017 class ImplementationCache {
2019 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
2020 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
2022 class Entry {
2023 final MethodSymbol cachedImpl;
2024 final Filter<Symbol> implFilter;
2025 final boolean checkResult;
2027 public Entry(MethodSymbol cachedImpl,
2028 Filter<Symbol> scopeFilter,
2029 boolean checkResult) {
2030 this.cachedImpl = cachedImpl;
2031 this.implFilter = scopeFilter;
2032 this.checkResult = checkResult;
2033 }
2035 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult) {
2036 return this.implFilter == scopeFilter &&
2037 this.checkResult == checkResult;
2038 }
2039 }
2041 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2042 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
2043 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
2044 if (cache == null) {
2045 cache = new HashMap<TypeSymbol, Entry>();
2046 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache));
2047 }
2048 Entry e = cache.get(origin);
2049 if (e == null ||
2050 !e.matches(implFilter, checkResult)) {
2051 MethodSymbol impl = implementationInternal(ms, origin, Types.this, checkResult, implFilter);
2052 cache.put(origin, new Entry(impl, implFilter, checkResult));
2053 return impl;
2054 }
2055 else {
2056 return e.cachedImpl;
2057 }
2058 }
2060 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, Types types, boolean checkResult, Filter<Symbol> implFilter) {
2061 for (Type t = origin.type; t.tag == CLASS || t.tag == TYPEVAR; t = types.supertype(t)) {
2062 while (t.tag == TYPEVAR)
2063 t = t.getUpperBound();
2064 TypeSymbol c = t.tsym;
2065 for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
2066 e.scope != null;
2067 e = e.next(implFilter)) {
2068 if (e.sym != null &&
2069 e.sym.overrides(ms, origin, types, checkResult))
2070 return (MethodSymbol)e.sym;
2071 }
2072 }
2073 return null;
2074 }
2075 }
2077 private ImplementationCache implCache = new ImplementationCache();
2079 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
2080 return implCache.get(ms, origin, checkResult, implFilter);
2081 }
2082 // </editor-fold>
2084 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
2085 public Scope membersClosure(Type site) {
2086 return membersClosure.visit(site);
2087 }
2089 UnaryVisitor<Scope> membersClosure = new UnaryVisitor<Scope>() {
2091 public Scope visitType(Type t, Void s) {
2092 return null;
2093 }
2095 @Override
2096 public Scope visitClassType(ClassType t, Void s) {
2097 ClassSymbol csym = (ClassSymbol)t.tsym;
2098 if (csym.membersClosure == null) {
2099 Scope membersClosure = new Scope(csym);
2100 for (Type i : interfaces(t)) {
2101 enterAll(visit(i), membersClosure);
2102 }
2103 enterAll(visit(supertype(t)), membersClosure);
2104 enterAll(csym.members(), membersClosure);
2105 csym.membersClosure = membersClosure;
2106 }
2107 return csym.membersClosure;
2108 }
2110 @Override
2111 public Scope visitTypeVar(TypeVar t, Void s) {
2112 return visit(t.getUpperBound());
2113 }
2115 public void enterAll(Scope s, Scope to) {
2116 if (s == null) return;
2117 List<Symbol> syms = List.nil();
2118 for (Scope.Entry e = s.elems ; e != null ; e = e.sibling) {
2119 syms = syms.prepend(e.sym);
2120 }
2121 for (Symbol sym : syms) {
2122 to.enter(sym);
2123 }
2124 }
2125 };
2126 // </editor-fold>
2128 /**
2129 * Does t have the same arguments as s? It is assumed that both
2130 * types are (possibly polymorphic) method types. Monomorphic
2131 * method types "have the same arguments", if their argument lists
2132 * are equal. Polymorphic method types "have the same arguments",
2133 * if they have the same arguments after renaming all type
2134 * variables of one to corresponding type variables in the other,
2135 * where correspondence is by position in the type parameter list.
2136 */
2137 public boolean hasSameArgs(Type t, Type s) {
2138 return hasSameArgs.visit(t, s);
2139 }
2140 // where
2141 private TypeRelation hasSameArgs = new TypeRelation() {
2143 public Boolean visitType(Type t, Type s) {
2144 throw new AssertionError();
2145 }
2147 @Override
2148 public Boolean visitMethodType(MethodType t, Type s) {
2149 return s.tag == METHOD
2150 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
2151 }
2153 @Override
2154 public Boolean visitForAll(ForAll t, Type s) {
2155 if (s.tag != FORALL)
2156 return false;
2158 ForAll forAll = (ForAll)s;
2159 return hasSameBounds(t, forAll)
2160 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
2161 }
2163 @Override
2164 public Boolean visitErrorType(ErrorType t, Type s) {
2165 return false;
2166 }
2167 };
2168 // </editor-fold>
2170 // <editor-fold defaultstate="collapsed" desc="subst">
2171 public List<Type> subst(List<Type> ts,
2172 List<Type> from,
2173 List<Type> to) {
2174 return new Subst(from, to).subst(ts);
2175 }
2177 /**
2178 * Substitute all occurrences of a type in `from' with the
2179 * corresponding type in `to' in 't'. Match lists `from' and `to'
2180 * from the right: If lists have different length, discard leading
2181 * elements of the longer list.
2182 */
2183 public Type subst(Type t, List<Type> from, List<Type> to) {
2184 return new Subst(from, to).subst(t);
2185 }
2187 private class Subst extends UnaryVisitor<Type> {
2188 List<Type> from;
2189 List<Type> to;
2191 public Subst(List<Type> from, List<Type> to) {
2192 int fromLength = from.length();
2193 int toLength = to.length();
2194 while (fromLength > toLength) {
2195 fromLength--;
2196 from = from.tail;
2197 }
2198 while (fromLength < toLength) {
2199 toLength--;
2200 to = to.tail;
2201 }
2202 this.from = from;
2203 this.to = to;
2204 }
2206 Type subst(Type t) {
2207 if (from.tail == null)
2208 return t;
2209 else
2210 return visit(t);
2211 }
2213 List<Type> subst(List<Type> ts) {
2214 if (from.tail == null)
2215 return ts;
2216 boolean wild = false;
2217 if (ts.nonEmpty() && from.nonEmpty()) {
2218 Type head1 = subst(ts.head);
2219 List<Type> tail1 = subst(ts.tail);
2220 if (head1 != ts.head || tail1 != ts.tail)
2221 return tail1.prepend(head1);
2222 }
2223 return ts;
2224 }
2226 public Type visitType(Type t, Void ignored) {
2227 return t;
2228 }
2230 @Override
2231 public Type visitMethodType(MethodType t, Void ignored) {
2232 List<Type> argtypes = subst(t.argtypes);
2233 Type restype = subst(t.restype);
2234 List<Type> thrown = subst(t.thrown);
2235 if (argtypes == t.argtypes &&
2236 restype == t.restype &&
2237 thrown == t.thrown)
2238 return t;
2239 else
2240 return new MethodType(argtypes, restype, thrown, t.tsym);
2241 }
2243 @Override
2244 public Type visitTypeVar(TypeVar t, Void ignored) {
2245 for (List<Type> from = this.from, to = this.to;
2246 from.nonEmpty();
2247 from = from.tail, to = to.tail) {
2248 if (t == from.head) {
2249 return to.head.withTypeVar(t);
2250 }
2251 }
2252 return t;
2253 }
2255 @Override
2256 public Type visitClassType(ClassType t, Void ignored) {
2257 if (!t.isCompound()) {
2258 List<Type> typarams = t.getTypeArguments();
2259 List<Type> typarams1 = subst(typarams);
2260 Type outer = t.getEnclosingType();
2261 Type outer1 = subst(outer);
2262 if (typarams1 == typarams && outer1 == outer)
2263 return t;
2264 else
2265 return new ClassType(outer1, typarams1, t.tsym);
2266 } else {
2267 Type st = subst(supertype(t));
2268 List<Type> is = upperBounds(subst(interfaces(t)));
2269 if (st == supertype(t) && is == interfaces(t))
2270 return t;
2271 else
2272 return makeCompoundType(is.prepend(st));
2273 }
2274 }
2276 @Override
2277 public Type visitWildcardType(WildcardType t, Void ignored) {
2278 Type bound = t.type;
2279 if (t.kind != BoundKind.UNBOUND)
2280 bound = subst(bound);
2281 if (bound == t.type) {
2282 return t;
2283 } else {
2284 if (t.isExtendsBound() && bound.isExtendsBound())
2285 bound = upperBound(bound);
2286 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2287 }
2288 }
2290 @Override
2291 public Type visitArrayType(ArrayType t, Void ignored) {
2292 Type elemtype = subst(t.elemtype);
2293 if (elemtype == t.elemtype)
2294 return t;
2295 else
2296 return new ArrayType(upperBound(elemtype), t.tsym);
2297 }
2299 @Override
2300 public Type visitForAll(ForAll t, Void ignored) {
2301 if (Type.containsAny(to, t.tvars)) {
2302 //perform alpha-renaming of free-variables in 't'
2303 //if 'to' types contain variables that are free in 't'
2304 List<Type> freevars = newInstances(t.tvars);
2305 t = new ForAll(freevars,
2306 Types.this.subst(t.qtype, t.tvars, freevars));
2307 }
2308 List<Type> tvars1 = substBounds(t.tvars, from, to);
2309 Type qtype1 = subst(t.qtype);
2310 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2311 return t;
2312 } else if (tvars1 == t.tvars) {
2313 return new ForAll(tvars1, qtype1);
2314 } else {
2315 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2316 }
2317 }
2319 @Override
2320 public Type visitErrorType(ErrorType t, Void ignored) {
2321 return t;
2322 }
2323 }
2325 public List<Type> substBounds(List<Type> tvars,
2326 List<Type> from,
2327 List<Type> to) {
2328 if (tvars.isEmpty())
2329 return tvars;
2330 ListBuffer<Type> newBoundsBuf = lb();
2331 boolean changed = false;
2332 // calculate new bounds
2333 for (Type t : tvars) {
2334 TypeVar tv = (TypeVar) t;
2335 Type bound = subst(tv.bound, from, to);
2336 if (bound != tv.bound)
2337 changed = true;
2338 newBoundsBuf.append(bound);
2339 }
2340 if (!changed)
2341 return tvars;
2342 ListBuffer<Type> newTvars = lb();
2343 // create new type variables without bounds
2344 for (Type t : tvars) {
2345 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2346 }
2347 // the new bounds should use the new type variables in place
2348 // of the old
2349 List<Type> newBounds = newBoundsBuf.toList();
2350 from = tvars;
2351 to = newTvars.toList();
2352 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2353 newBounds.head = subst(newBounds.head, from, to);
2354 }
2355 newBounds = newBoundsBuf.toList();
2356 // set the bounds of new type variables to the new bounds
2357 for (Type t : newTvars.toList()) {
2358 TypeVar tv = (TypeVar) t;
2359 tv.bound = newBounds.head;
2360 newBounds = newBounds.tail;
2361 }
2362 return newTvars.toList();
2363 }
2365 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2366 Type bound1 = subst(t.bound, from, to);
2367 if (bound1 == t.bound)
2368 return t;
2369 else {
2370 // create new type variable without bounds
2371 TypeVar tv = new TypeVar(t.tsym, null, syms.botType);
2372 // the new bound should use the new type variable in place
2373 // of the old
2374 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv));
2375 return tv;
2376 }
2377 }
2378 // </editor-fold>
2380 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2381 /**
2382 * Does t have the same bounds for quantified variables as s?
2383 */
2384 boolean hasSameBounds(ForAll t, ForAll s) {
2385 List<Type> l1 = t.tvars;
2386 List<Type> l2 = s.tvars;
2387 while (l1.nonEmpty() && l2.nonEmpty() &&
2388 isSameType(l1.head.getUpperBound(),
2389 subst(l2.head.getUpperBound(),
2390 s.tvars,
2391 t.tvars))) {
2392 l1 = l1.tail;
2393 l2 = l2.tail;
2394 }
2395 return l1.isEmpty() && l2.isEmpty();
2396 }
2397 // </editor-fold>
2399 // <editor-fold defaultstate="collapsed" desc="newInstances">
2400 /** Create new vector of type variables from list of variables
2401 * changing all recursive bounds from old to new list.
2402 */
2403 public List<Type> newInstances(List<Type> tvars) {
2404 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2405 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2406 TypeVar tv = (TypeVar) l.head;
2407 tv.bound = subst(tv.bound, tvars, tvars1);
2408 }
2409 return tvars1;
2410 }
2411 static private Mapping newInstanceFun = new Mapping("newInstanceFun") {
2412 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2413 };
2414 // </editor-fold>
2416 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2417 public Type createErrorType(Type originalType) {
2418 return new ErrorType(originalType, syms.errSymbol);
2419 }
2421 public Type createErrorType(ClassSymbol c, Type originalType) {
2422 return new ErrorType(c, originalType);
2423 }
2425 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
2426 return new ErrorType(name, container, originalType);
2427 }
2428 // </editor-fold>
2430 // <editor-fold defaultstate="collapsed" desc="rank">
2431 /**
2432 * The rank of a class is the length of the longest path between
2433 * the class and java.lang.Object in the class inheritance
2434 * graph. Undefined for all but reference types.
2435 */
2436 public int rank(Type t) {
2437 switch(t.tag) {
2438 case CLASS: {
2439 ClassType cls = (ClassType)t;
2440 if (cls.rank_field < 0) {
2441 Name fullname = cls.tsym.getQualifiedName();
2442 if (fullname == names.java_lang_Object)
2443 cls.rank_field = 0;
2444 else {
2445 int r = rank(supertype(cls));
2446 for (List<Type> l = interfaces(cls);
2447 l.nonEmpty();
2448 l = l.tail) {
2449 if (rank(l.head) > r)
2450 r = rank(l.head);
2451 }
2452 cls.rank_field = r + 1;
2453 }
2454 }
2455 return cls.rank_field;
2456 }
2457 case TYPEVAR: {
2458 TypeVar tvar = (TypeVar)t;
2459 if (tvar.rank_field < 0) {
2460 int r = rank(supertype(tvar));
2461 for (List<Type> l = interfaces(tvar);
2462 l.nonEmpty();
2463 l = l.tail) {
2464 if (rank(l.head) > r) r = rank(l.head);
2465 }
2466 tvar.rank_field = r + 1;
2467 }
2468 return tvar.rank_field;
2469 }
2470 case ERROR:
2471 return 0;
2472 default:
2473 throw new AssertionError();
2474 }
2475 }
2476 // </editor-fold>
2478 /**
2479 * Helper method for generating a string representation of a given type
2480 * accordingly to a given locale
2481 */
2482 public String toString(Type t, Locale locale) {
2483 return Printer.createStandardPrinter(messages).visit(t, locale);
2484 }
2486 /**
2487 * Helper method for generating a string representation of a given type
2488 * accordingly to a given locale
2489 */
2490 public String toString(Symbol t, Locale locale) {
2491 return Printer.createStandardPrinter(messages).visit(t, locale);
2492 }
2494 // <editor-fold defaultstate="collapsed" desc="toString">
2495 /**
2496 * This toString is slightly more descriptive than the one on Type.
2497 *
2498 * @deprecated Types.toString(Type t, Locale l) provides better support
2499 * for localization
2500 */
2501 @Deprecated
2502 public String toString(Type t) {
2503 if (t.tag == FORALL) {
2504 ForAll forAll = (ForAll)t;
2505 return typaramsString(forAll.tvars) + forAll.qtype;
2506 }
2507 return "" + t;
2508 }
2509 // where
2510 private String typaramsString(List<Type> tvars) {
2511 StringBuffer s = new StringBuffer();
2512 s.append('<');
2513 boolean first = true;
2514 for (Type t : tvars) {
2515 if (!first) s.append(", ");
2516 first = false;
2517 appendTyparamString(((TypeVar)t), s);
2518 }
2519 s.append('>');
2520 return s.toString();
2521 }
2522 private void appendTyparamString(TypeVar t, StringBuffer buf) {
2523 buf.append(t);
2524 if (t.bound == null ||
2525 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
2526 return;
2527 buf.append(" extends "); // Java syntax; no need for i18n
2528 Type bound = t.bound;
2529 if (!bound.isCompound()) {
2530 buf.append(bound);
2531 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
2532 buf.append(supertype(t));
2533 for (Type intf : interfaces(t)) {
2534 buf.append('&');
2535 buf.append(intf);
2536 }
2537 } else {
2538 // No superclass was given in bounds.
2539 // In this case, supertype is Object, erasure is first interface.
2540 boolean first = true;
2541 for (Type intf : interfaces(t)) {
2542 if (!first) buf.append('&');
2543 first = false;
2544 buf.append(intf);
2545 }
2546 }
2547 }
2548 // </editor-fold>
2550 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
2551 /**
2552 * A cache for closures.
2553 *
2554 * <p>A closure is a list of all the supertypes and interfaces of
2555 * a class or interface type, ordered by ClassSymbol.precedes
2556 * (that is, subclasses come first, arbitrary but fixed
2557 * otherwise).
2558 */
2559 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
2561 /**
2562 * Returns the closure of a class or interface type.
2563 */
2564 public List<Type> closure(Type t) {
2565 List<Type> cl = closureCache.get(t);
2566 if (cl == null) {
2567 Type st = supertype(t);
2568 if (!t.isCompound()) {
2569 if (st.tag == CLASS) {
2570 cl = insert(closure(st), t);
2571 } else if (st.tag == TYPEVAR) {
2572 cl = closure(st).prepend(t);
2573 } else {
2574 cl = List.of(t);
2575 }
2576 } else {
2577 cl = closure(supertype(t));
2578 }
2579 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
2580 cl = union(cl, closure(l.head));
2581 closureCache.put(t, cl);
2582 }
2583 return cl;
2584 }
2586 /**
2587 * Insert a type in a closure
2588 */
2589 public List<Type> insert(List<Type> cl, Type t) {
2590 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
2591 return cl.prepend(t);
2592 } else if (cl.head.tsym.precedes(t.tsym, this)) {
2593 return insert(cl.tail, t).prepend(cl.head);
2594 } else {
2595 return cl;
2596 }
2597 }
2599 /**
2600 * Form the union of two closures
2601 */
2602 public List<Type> union(List<Type> cl1, List<Type> cl2) {
2603 if (cl1.isEmpty()) {
2604 return cl2;
2605 } else if (cl2.isEmpty()) {
2606 return cl1;
2607 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
2608 return union(cl1.tail, cl2).prepend(cl1.head);
2609 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
2610 return union(cl1, cl2.tail).prepend(cl2.head);
2611 } else {
2612 return union(cl1.tail, cl2.tail).prepend(cl1.head);
2613 }
2614 }
2616 /**
2617 * Intersect two closures
2618 */
2619 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
2620 if (cl1 == cl2)
2621 return cl1;
2622 if (cl1.isEmpty() || cl2.isEmpty())
2623 return List.nil();
2624 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
2625 return intersect(cl1.tail, cl2);
2626 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
2627 return intersect(cl1, cl2.tail);
2628 if (isSameType(cl1.head, cl2.head))
2629 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
2630 if (cl1.head.tsym == cl2.head.tsym &&
2631 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
2632 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
2633 Type merge = merge(cl1.head,cl2.head);
2634 return intersect(cl1.tail, cl2.tail).prepend(merge);
2635 }
2636 if (cl1.head.isRaw() || cl2.head.isRaw())
2637 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
2638 }
2639 return intersect(cl1.tail, cl2.tail);
2640 }
2641 // where
2642 class TypePair {
2643 final Type t1;
2644 final Type t2;
2645 TypePair(Type t1, Type t2) {
2646 this.t1 = t1;
2647 this.t2 = t2;
2648 }
2649 @Override
2650 public int hashCode() {
2651 return 127 * Types.hashCode(t1) + Types.hashCode(t2);
2652 }
2653 @Override
2654 public boolean equals(Object obj) {
2655 if (!(obj instanceof TypePair))
2656 return false;
2657 TypePair typePair = (TypePair)obj;
2658 return isSameType(t1, typePair.t1)
2659 && isSameType(t2, typePair.t2);
2660 }
2661 }
2662 Set<TypePair> mergeCache = new HashSet<TypePair>();
2663 private Type merge(Type c1, Type c2) {
2664 ClassType class1 = (ClassType) c1;
2665 List<Type> act1 = class1.getTypeArguments();
2666 ClassType class2 = (ClassType) c2;
2667 List<Type> act2 = class2.getTypeArguments();
2668 ListBuffer<Type> merged = new ListBuffer<Type>();
2669 List<Type> typarams = class1.tsym.type.getTypeArguments();
2671 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
2672 if (containsType(act1.head, act2.head)) {
2673 merged.append(act1.head);
2674 } else if (containsType(act2.head, act1.head)) {
2675 merged.append(act2.head);
2676 } else {
2677 TypePair pair = new TypePair(c1, c2);
2678 Type m;
2679 if (mergeCache.add(pair)) {
2680 m = new WildcardType(lub(upperBound(act1.head),
2681 upperBound(act2.head)),
2682 BoundKind.EXTENDS,
2683 syms.boundClass);
2684 mergeCache.remove(pair);
2685 } else {
2686 m = new WildcardType(syms.objectType,
2687 BoundKind.UNBOUND,
2688 syms.boundClass);
2689 }
2690 merged.append(m.withTypeVar(typarams.head));
2691 }
2692 act1 = act1.tail;
2693 act2 = act2.tail;
2694 typarams = typarams.tail;
2695 }
2696 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
2697 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
2698 }
2700 /**
2701 * Return the minimum type of a closure, a compound type if no
2702 * unique minimum exists.
2703 */
2704 private Type compoundMin(List<Type> cl) {
2705 if (cl.isEmpty()) return syms.objectType;
2706 List<Type> compound = closureMin(cl);
2707 if (compound.isEmpty())
2708 return null;
2709 else if (compound.tail.isEmpty())
2710 return compound.head;
2711 else
2712 return makeCompoundType(compound);
2713 }
2715 /**
2716 * Return the minimum types of a closure, suitable for computing
2717 * compoundMin or glb.
2718 */
2719 private List<Type> closureMin(List<Type> cl) {
2720 ListBuffer<Type> classes = lb();
2721 ListBuffer<Type> interfaces = lb();
2722 while (!cl.isEmpty()) {
2723 Type current = cl.head;
2724 if (current.isInterface())
2725 interfaces.append(current);
2726 else
2727 classes.append(current);
2728 ListBuffer<Type> candidates = lb();
2729 for (Type t : cl.tail) {
2730 if (!isSubtypeNoCapture(current, t))
2731 candidates.append(t);
2732 }
2733 cl = candidates.toList();
2734 }
2735 return classes.appendList(interfaces).toList();
2736 }
2738 /**
2739 * Return the least upper bound of pair of types. if the lub does
2740 * not exist return null.
2741 */
2742 public Type lub(Type t1, Type t2) {
2743 return lub(List.of(t1, t2));
2744 }
2746 /**
2747 * Return the least upper bound (lub) of set of types. If the lub
2748 * does not exist return the type of null (bottom).
2749 */
2750 public Type lub(List<Type> ts) {
2751 final int ARRAY_BOUND = 1;
2752 final int CLASS_BOUND = 2;
2753 int boundkind = 0;
2754 for (Type t : ts) {
2755 switch (t.tag) {
2756 case CLASS:
2757 boundkind |= CLASS_BOUND;
2758 break;
2759 case ARRAY:
2760 boundkind |= ARRAY_BOUND;
2761 break;
2762 case TYPEVAR:
2763 do {
2764 t = t.getUpperBound();
2765 } while (t.tag == TYPEVAR);
2766 if (t.tag == ARRAY) {
2767 boundkind |= ARRAY_BOUND;
2768 } else {
2769 boundkind |= CLASS_BOUND;
2770 }
2771 break;
2772 default:
2773 if (t.isPrimitive())
2774 return syms.errType;
2775 }
2776 }
2777 switch (boundkind) {
2778 case 0:
2779 return syms.botType;
2781 case ARRAY_BOUND:
2782 // calculate lub(A[], B[])
2783 List<Type> elements = Type.map(ts, elemTypeFun);
2784 for (Type t : elements) {
2785 if (t.isPrimitive()) {
2786 // if a primitive type is found, then return
2787 // arraySuperType unless all the types are the
2788 // same
2789 Type first = ts.head;
2790 for (Type s : ts.tail) {
2791 if (!isSameType(first, s)) {
2792 // lub(int[], B[]) is Cloneable & Serializable
2793 return arraySuperType();
2794 }
2795 }
2796 // all the array types are the same, return one
2797 // lub(int[], int[]) is int[]
2798 return first;
2799 }
2800 }
2801 // lub(A[], B[]) is lub(A, B)[]
2802 return new ArrayType(lub(elements), syms.arrayClass);
2804 case CLASS_BOUND:
2805 // calculate lub(A, B)
2806 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
2807 ts = ts.tail;
2808 Assert.check(!ts.isEmpty());
2809 List<Type> cl = closure(ts.head);
2810 for (Type t : ts.tail) {
2811 if (t.tag == CLASS || t.tag == TYPEVAR)
2812 cl = intersect(cl, closure(t));
2813 }
2814 return compoundMin(cl);
2816 default:
2817 // calculate lub(A, B[])
2818 List<Type> classes = List.of(arraySuperType());
2819 for (Type t : ts) {
2820 if (t.tag != ARRAY) // Filter out any arrays
2821 classes = classes.prepend(t);
2822 }
2823 // lub(A, B[]) is lub(A, arraySuperType)
2824 return lub(classes);
2825 }
2826 }
2827 // where
2828 private Type arraySuperType = null;
2829 private Type arraySuperType() {
2830 // initialized lazily to avoid problems during compiler startup
2831 if (arraySuperType == null) {
2832 synchronized (this) {
2833 if (arraySuperType == null) {
2834 // JLS 10.8: all arrays implement Cloneable and Serializable.
2835 arraySuperType = makeCompoundType(List.of(syms.serializableType,
2836 syms.cloneableType),
2837 syms.objectType);
2838 }
2839 }
2840 }
2841 return arraySuperType;
2842 }
2843 // </editor-fold>
2845 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
2846 public Type glb(List<Type> ts) {
2847 Type t1 = ts.head;
2848 for (Type t2 : ts.tail) {
2849 if (t1.isErroneous())
2850 return t1;
2851 t1 = glb(t1, t2);
2852 }
2853 return t1;
2854 }
2855 //where
2856 public Type glb(Type t, Type s) {
2857 if (s == null)
2858 return t;
2859 else if (t.isPrimitive() || s.isPrimitive())
2860 return syms.errType;
2861 else if (isSubtypeNoCapture(t, s))
2862 return t;
2863 else if (isSubtypeNoCapture(s, t))
2864 return s;
2866 List<Type> closure = union(closure(t), closure(s));
2867 List<Type> bounds = closureMin(closure);
2869 if (bounds.isEmpty()) { // length == 0
2870 return syms.objectType;
2871 } else if (bounds.tail.isEmpty()) { // length == 1
2872 return bounds.head;
2873 } else { // length > 1
2874 int classCount = 0;
2875 for (Type bound : bounds)
2876 if (!bound.isInterface())
2877 classCount++;
2878 if (classCount > 1)
2879 return createErrorType(t);
2880 }
2881 return makeCompoundType(bounds);
2882 }
2883 // </editor-fold>
2885 // <editor-fold defaultstate="collapsed" desc="hashCode">
2886 /**
2887 * Compute a hash code on a type.
2888 */
2889 public static int hashCode(Type t) {
2890 return hashCode.visit(t);
2891 }
2892 // where
2893 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
2895 public Integer visitType(Type t, Void ignored) {
2896 return t.tag;
2897 }
2899 @Override
2900 public Integer visitClassType(ClassType t, Void ignored) {
2901 int result = visit(t.getEnclosingType());
2902 result *= 127;
2903 result += t.tsym.flatName().hashCode();
2904 for (Type s : t.getTypeArguments()) {
2905 result *= 127;
2906 result += visit(s);
2907 }
2908 return result;
2909 }
2911 @Override
2912 public Integer visitWildcardType(WildcardType t, Void ignored) {
2913 int result = t.kind.hashCode();
2914 if (t.type != null) {
2915 result *= 127;
2916 result += visit(t.type);
2917 }
2918 return result;
2919 }
2921 @Override
2922 public Integer visitArrayType(ArrayType t, Void ignored) {
2923 return visit(t.elemtype) + 12;
2924 }
2926 @Override
2927 public Integer visitTypeVar(TypeVar t, Void ignored) {
2928 return System.identityHashCode(t.tsym);
2929 }
2931 @Override
2932 public Integer visitUndetVar(UndetVar t, Void ignored) {
2933 return System.identityHashCode(t);
2934 }
2936 @Override
2937 public Integer visitErrorType(ErrorType t, Void ignored) {
2938 return 0;
2939 }
2940 };
2941 // </editor-fold>
2943 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
2944 /**
2945 * Does t have a result that is a subtype of the result type of s,
2946 * suitable for covariant returns? It is assumed that both types
2947 * are (possibly polymorphic) method types. Monomorphic method
2948 * types are handled in the obvious way. Polymorphic method types
2949 * require renaming all type variables of one to corresponding
2950 * type variables in the other, where correspondence is by
2951 * position in the type parameter list. */
2952 public boolean resultSubtype(Type t, Type s, Warner warner) {
2953 List<Type> tvars = t.getTypeArguments();
2954 List<Type> svars = s.getTypeArguments();
2955 Type tres = t.getReturnType();
2956 Type sres = subst(s.getReturnType(), svars, tvars);
2957 return covariantReturnType(tres, sres, warner);
2958 }
2960 /**
2961 * Return-Type-Substitutable.
2962 * @see <a href="http://java.sun.com/docs/books/jls/">The Java
2963 * Language Specification, Third Ed. (8.4.5)</a>
2964 */
2965 public boolean returnTypeSubstitutable(Type r1, Type r2) {
2966 if (hasSameArgs(r1, r2))
2967 return resultSubtype(r1, r2, Warner.noWarnings);
2968 else
2969 return covariantReturnType(r1.getReturnType(),
2970 erasure(r2.getReturnType()),
2971 Warner.noWarnings);
2972 }
2974 public boolean returnTypeSubstitutable(Type r1,
2975 Type r2, Type r2res,
2976 Warner warner) {
2977 if (isSameType(r1.getReturnType(), r2res))
2978 return true;
2979 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
2980 return false;
2982 if (hasSameArgs(r1, r2))
2983 return covariantReturnType(r1.getReturnType(), r2res, warner);
2984 if (!source.allowCovariantReturns())
2985 return false;
2986 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
2987 return true;
2988 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
2989 return false;
2990 warner.warn(LintCategory.UNCHECKED);
2991 return true;
2992 }
2994 /**
2995 * Is t an appropriate return type in an overrider for a
2996 * method that returns s?
2997 */
2998 public boolean covariantReturnType(Type t, Type s, Warner warner) {
2999 return
3000 isSameType(t, s) ||
3001 source.allowCovariantReturns() &&
3002 !t.isPrimitive() &&
3003 !s.isPrimitive() &&
3004 isAssignable(t, s, warner);
3005 }
3006 // </editor-fold>
3008 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
3009 /**
3010 * Return the class that boxes the given primitive.
3011 */
3012 public ClassSymbol boxedClass(Type t) {
3013 return reader.enterClass(syms.boxedName[t.tag]);
3014 }
3016 /**
3017 * Return the boxed type if 't' is primitive, otherwise return 't' itself.
3018 */
3019 public Type boxedTypeOrType(Type t) {
3020 return t.isPrimitive() ?
3021 boxedClass(t).type :
3022 t;
3023 }
3025 /**
3026 * Return the primitive type corresponding to a boxed type.
3027 */
3028 public Type unboxedType(Type t) {
3029 if (allowBoxing) {
3030 for (int i=0; i<syms.boxedName.length; i++) {
3031 Name box = syms.boxedName[i];
3032 if (box != null &&
3033 asSuper(t, reader.enterClass(box)) != null)
3034 return syms.typeOfTag[i];
3035 }
3036 }
3037 return Type.noType;
3038 }
3039 // </editor-fold>
3041 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3042 /*
3043 * JLS 3rd Ed. 5.1.10 Capture Conversion:
3044 *
3045 * Let G name a generic type declaration with n formal type
3046 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3047 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3048 * where, for 1 <= i <= n:
3049 *
3050 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3051 * Si is a fresh type variable whose upper bound is
3052 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3053 * type.
3054 *
3055 * + If Ti is a wildcard type argument of the form ? extends Bi,
3056 * then Si is a fresh type variable whose upper bound is
3057 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3058 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3059 * a compile-time error if for any two classes (not interfaces)
3060 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3061 *
3062 * + If Ti is a wildcard type argument of the form ? super Bi,
3063 * then Si is a fresh type variable whose upper bound is
3064 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3065 *
3066 * + Otherwise, Si = Ti.
3067 *
3068 * Capture conversion on any type other than a parameterized type
3069 * (4.5) acts as an identity conversion (5.1.1). Capture
3070 * conversions never require a special action at run time and
3071 * therefore never throw an exception at run time.
3072 *
3073 * Capture conversion is not applied recursively.
3074 */
3075 /**
3076 * Capture conversion as specified by JLS 3rd Ed.
3077 */
3079 public List<Type> capture(List<Type> ts) {
3080 List<Type> buf = List.nil();
3081 for (Type t : ts) {
3082 buf = buf.prepend(capture(t));
3083 }
3084 return buf.reverse();
3085 }
3086 public Type capture(Type t) {
3087 if (t.tag != CLASS)
3088 return t;
3089 if (t.getEnclosingType() != Type.noType) {
3090 Type capturedEncl = capture(t.getEnclosingType());
3091 if (capturedEncl != t.getEnclosingType()) {
3092 Type type1 = memberType(capturedEncl, t.tsym);
3093 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
3094 }
3095 }
3096 ClassType cls = (ClassType)t;
3097 if (cls.isRaw() || !cls.isParameterized())
3098 return cls;
3100 ClassType G = (ClassType)cls.asElement().asType();
3101 List<Type> A = G.getTypeArguments();
3102 List<Type> T = cls.getTypeArguments();
3103 List<Type> S = freshTypeVariables(T);
3105 List<Type> currentA = A;
3106 List<Type> currentT = T;
3107 List<Type> currentS = S;
3108 boolean captured = false;
3109 while (!currentA.isEmpty() &&
3110 !currentT.isEmpty() &&
3111 !currentS.isEmpty()) {
3112 if (currentS.head != currentT.head) {
3113 captured = true;
3114 WildcardType Ti = (WildcardType)currentT.head;
3115 Type Ui = currentA.head.getUpperBound();
3116 CapturedType Si = (CapturedType)currentS.head;
3117 if (Ui == null)
3118 Ui = syms.objectType;
3119 switch (Ti.kind) {
3120 case UNBOUND:
3121 Si.bound = subst(Ui, A, S);
3122 Si.lower = syms.botType;
3123 break;
3124 case EXTENDS:
3125 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3126 Si.lower = syms.botType;
3127 break;
3128 case SUPER:
3129 Si.bound = subst(Ui, A, S);
3130 Si.lower = Ti.getSuperBound();
3131 break;
3132 }
3133 if (Si.bound == Si.lower)
3134 currentS.head = Si.bound;
3135 }
3136 currentA = currentA.tail;
3137 currentT = currentT.tail;
3138 currentS = currentS.tail;
3139 }
3140 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3141 return erasure(t); // some "rare" type involved
3143 if (captured)
3144 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3145 else
3146 return t;
3147 }
3148 // where
3149 public List<Type> freshTypeVariables(List<Type> types) {
3150 ListBuffer<Type> result = lb();
3151 for (Type t : types) {
3152 if (t.tag == WILDCARD) {
3153 Type bound = ((WildcardType)t).getExtendsBound();
3154 if (bound == null)
3155 bound = syms.objectType;
3156 result.append(new CapturedType(capturedName,
3157 syms.noSymbol,
3158 bound,
3159 syms.botType,
3160 (WildcardType)t));
3161 } else {
3162 result.append(t);
3163 }
3164 }
3165 return result.toList();
3166 }
3167 // </editor-fold>
3169 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3170 private List<Type> upperBounds(List<Type> ss) {
3171 if (ss.isEmpty()) return ss;
3172 Type head = upperBound(ss.head);
3173 List<Type> tail = upperBounds(ss.tail);
3174 if (head != ss.head || tail != ss.tail)
3175 return tail.prepend(head);
3176 else
3177 return ss;
3178 }
3180 private boolean sideCast(Type from, Type to, Warner warn) {
3181 // We are casting from type $from$ to type $to$, which are
3182 // non-final unrelated types. This method
3183 // tries to reject a cast by transferring type parameters
3184 // from $to$ to $from$ by common superinterfaces.
3185 boolean reverse = false;
3186 Type target = to;
3187 if ((to.tsym.flags() & INTERFACE) == 0) {
3188 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3189 reverse = true;
3190 to = from;
3191 from = target;
3192 }
3193 List<Type> commonSupers = superClosure(to, erasure(from));
3194 boolean giveWarning = commonSupers.isEmpty();
3195 // The arguments to the supers could be unified here to
3196 // get a more accurate analysis
3197 while (commonSupers.nonEmpty()) {
3198 Type t1 = asSuper(from, commonSupers.head.tsym);
3199 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3200 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3201 return false;
3202 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3203 commonSupers = commonSupers.tail;
3204 }
3205 if (giveWarning && !isReifiable(reverse ? from : to))
3206 warn.warn(LintCategory.UNCHECKED);
3207 if (!source.allowCovariantReturns())
3208 // reject if there is a common method signature with
3209 // incompatible return types.
3210 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3211 return true;
3212 }
3214 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3215 // We are casting from type $from$ to type $to$, which are
3216 // unrelated types one of which is final and the other of
3217 // which is an interface. This method
3218 // tries to reject a cast by transferring type parameters
3219 // from the final class to the interface.
3220 boolean reverse = false;
3221 Type target = to;
3222 if ((to.tsym.flags() & INTERFACE) == 0) {
3223 Assert.check((from.tsym.flags() & INTERFACE) != 0);
3224 reverse = true;
3225 to = from;
3226 from = target;
3227 }
3228 Assert.check((from.tsym.flags() & FINAL) != 0);
3229 Type t1 = asSuper(from, to.tsym);
3230 if (t1 == null) return false;
3231 Type t2 = to;
3232 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3233 return false;
3234 if (!source.allowCovariantReturns())
3235 // reject if there is a common method signature with
3236 // incompatible return types.
3237 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3238 if (!isReifiable(target) &&
3239 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3240 warn.warn(LintCategory.UNCHECKED);
3241 return true;
3242 }
3244 private boolean giveWarning(Type from, Type to) {
3245 Type subFrom = asSub(from, to.tsym);
3246 return to.isParameterized() &&
3247 (!(isUnbounded(to) ||
3248 isSubtype(from, to) ||
3249 ((subFrom != null) && containsType(to.allparams(), subFrom.allparams()))));
3250 }
3252 private List<Type> superClosure(Type t, Type s) {
3253 List<Type> cl = List.nil();
3254 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3255 if (isSubtype(s, erasure(l.head))) {
3256 cl = insert(cl, l.head);
3257 } else {
3258 cl = union(cl, superClosure(l.head, s));
3259 }
3260 }
3261 return cl;
3262 }
3264 private boolean containsTypeEquivalent(Type t, Type s) {
3265 return
3266 isSameType(t, s) || // shortcut
3267 containsType(t, s) && containsType(s, t);
3268 }
3270 // <editor-fold defaultstate="collapsed" desc="adapt">
3271 /**
3272 * Adapt a type by computing a substitution which maps a source
3273 * type to a target type.
3274 *
3275 * @param source the source type
3276 * @param target the target type
3277 * @param from the type variables of the computed substitution
3278 * @param to the types of the computed substitution.
3279 */
3280 public void adapt(Type source,
3281 Type target,
3282 ListBuffer<Type> from,
3283 ListBuffer<Type> to) throws AdaptFailure {
3284 new Adapter(from, to).adapt(source, target);
3285 }
3287 class Adapter extends SimpleVisitor<Void, Type> {
3289 ListBuffer<Type> from;
3290 ListBuffer<Type> to;
3291 Map<Symbol,Type> mapping;
3293 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
3294 this.from = from;
3295 this.to = to;
3296 mapping = new HashMap<Symbol,Type>();
3297 }
3299 public void adapt(Type source, Type target) throws AdaptFailure {
3300 visit(source, target);
3301 List<Type> fromList = from.toList();
3302 List<Type> toList = to.toList();
3303 while (!fromList.isEmpty()) {
3304 Type val = mapping.get(fromList.head.tsym);
3305 if (toList.head != val)
3306 toList.head = val;
3307 fromList = fromList.tail;
3308 toList = toList.tail;
3309 }
3310 }
3312 @Override
3313 public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
3314 if (target.tag == CLASS)
3315 adaptRecursive(source.allparams(), target.allparams());
3316 return null;
3317 }
3319 @Override
3320 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
3321 if (target.tag == ARRAY)
3322 adaptRecursive(elemtype(source), elemtype(target));
3323 return null;
3324 }
3326 @Override
3327 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
3328 if (source.isExtendsBound())
3329 adaptRecursive(upperBound(source), upperBound(target));
3330 else if (source.isSuperBound())
3331 adaptRecursive(lowerBound(source), lowerBound(target));
3332 return null;
3333 }
3335 @Override
3336 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
3337 // Check to see if there is
3338 // already a mapping for $source$, in which case
3339 // the old mapping will be merged with the new
3340 Type val = mapping.get(source.tsym);
3341 if (val != null) {
3342 if (val.isSuperBound() && target.isSuperBound()) {
3343 val = isSubtype(lowerBound(val), lowerBound(target))
3344 ? target : val;
3345 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3346 val = isSubtype(upperBound(val), upperBound(target))
3347 ? val : target;
3348 } else if (!isSameType(val, target)) {
3349 throw new AdaptFailure();
3350 }
3351 } else {
3352 val = target;
3353 from.append(source);
3354 to.append(target);
3355 }
3356 mapping.put(source.tsym, val);
3357 return null;
3358 }
3360 @Override
3361 public Void visitType(Type source, Type target) {
3362 return null;
3363 }
3365 private Set<TypePair> cache = new HashSet<TypePair>();
3367 private void adaptRecursive(Type source, Type target) {
3368 TypePair pair = new TypePair(source, target);
3369 if (cache.add(pair)) {
3370 try {
3371 visit(source, target);
3372 } finally {
3373 cache.remove(pair);
3374 }
3375 }
3376 }
3378 private void adaptRecursive(List<Type> source, List<Type> target) {
3379 if (source.length() == target.length()) {
3380 while (source.nonEmpty()) {
3381 adaptRecursive(source.head, target.head);
3382 source = source.tail;
3383 target = target.tail;
3384 }
3385 }
3386 }
3387 }
3389 public static class AdaptFailure extends RuntimeException {
3390 static final long serialVersionUID = -7490231548272701566L;
3391 }
3393 private void adaptSelf(Type t,
3394 ListBuffer<Type> from,
3395 ListBuffer<Type> to) {
3396 try {
3397 //if (t.tsym.type != t)
3398 adapt(t.tsym.type, t, from, to);
3399 } catch (AdaptFailure ex) {
3400 // Adapt should never fail calculating a mapping from
3401 // t.tsym.type to t as there can be no merge problem.
3402 throw new AssertionError(ex);
3403 }
3404 }
3405 // </editor-fold>
3407 /**
3408 * Rewrite all type variables (universal quantifiers) in the given
3409 * type to wildcards (existential quantifiers). This is used to
3410 * determine if a cast is allowed. For example, if high is true
3411 * and {@code T <: Number}, then {@code List<T>} is rewritten to
3412 * {@code List<? extends Number>}. Since {@code List<Integer> <:
3413 * List<? extends Number>} a {@code List<T>} can be cast to {@code
3414 * List<Integer>} with a warning.
3415 * @param t a type
3416 * @param high if true return an upper bound; otherwise a lower
3417 * bound
3418 * @param rewriteTypeVars only rewrite captured wildcards if false;
3419 * otherwise rewrite all type variables
3420 * @return the type rewritten with wildcards (existential
3421 * quantifiers) only
3422 */
3423 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
3424 return new Rewriter(high, rewriteTypeVars).visit(t);
3425 }
3427 class Rewriter extends UnaryVisitor<Type> {
3429 boolean high;
3430 boolean rewriteTypeVars;
3432 Rewriter(boolean high, boolean rewriteTypeVars) {
3433 this.high = high;
3434 this.rewriteTypeVars = rewriteTypeVars;
3435 }
3437 @Override
3438 public Type visitClassType(ClassType t, Void s) {
3439 ListBuffer<Type> rewritten = new ListBuffer<Type>();
3440 boolean changed = false;
3441 for (Type arg : t.allparams()) {
3442 Type bound = visit(arg);
3443 if (arg != bound) {
3444 changed = true;
3445 }
3446 rewritten.append(bound);
3447 }
3448 if (changed)
3449 return subst(t.tsym.type,
3450 t.tsym.type.allparams(),
3451 rewritten.toList());
3452 else
3453 return t;
3454 }
3456 public Type visitType(Type t, Void s) {
3457 return high ? upperBound(t) : lowerBound(t);
3458 }
3460 @Override
3461 public Type visitCapturedType(CapturedType t, Void s) {
3462 Type bound = visitWildcardType(t.wildcard, null);
3463 return (bound.contains(t)) ?
3464 erasure(bound) :
3465 bound;
3466 }
3468 @Override
3469 public Type visitTypeVar(TypeVar t, Void s) {
3470 if (rewriteTypeVars) {
3471 Type bound = high ?
3472 (t.bound.contains(t) ?
3473 erasure(t.bound) :
3474 visit(t.bound)) :
3475 syms.botType;
3476 return rewriteAsWildcardType(bound, t);
3477 }
3478 else
3479 return t;
3480 }
3482 @Override
3483 public Type visitWildcardType(WildcardType t, Void s) {
3484 Type bound = high ? t.getExtendsBound() :
3485 t.getSuperBound();
3486 if (bound == null)
3487 bound = high ? syms.objectType : syms.botType;
3488 return rewriteAsWildcardType(visit(bound), t.bound);
3489 }
3491 private Type rewriteAsWildcardType(Type bound, TypeVar formal) {
3492 return high ?
3493 makeExtendsWildcard(B(bound), formal) :
3494 makeSuperWildcard(B(bound), formal);
3495 }
3497 Type B(Type t) {
3498 while (t.tag == WILDCARD) {
3499 WildcardType w = (WildcardType)t;
3500 t = high ?
3501 w.getExtendsBound() :
3502 w.getSuperBound();
3503 if (t == null) {
3504 t = high ? syms.objectType : syms.botType;
3505 }
3506 }
3507 return t;
3508 }
3509 }
3512 /**
3513 * Create a wildcard with the given upper (extends) bound; create
3514 * an unbounded wildcard if bound is Object.
3515 *
3516 * @param bound the upper bound
3517 * @param formal the formal type parameter that will be
3518 * substituted by the wildcard
3519 */
3520 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
3521 if (bound == syms.objectType) {
3522 return new WildcardType(syms.objectType,
3523 BoundKind.UNBOUND,
3524 syms.boundClass,
3525 formal);
3526 } else {
3527 return new WildcardType(bound,
3528 BoundKind.EXTENDS,
3529 syms.boundClass,
3530 formal);
3531 }
3532 }
3534 /**
3535 * Create a wildcard with the given lower (super) bound; create an
3536 * unbounded wildcard if bound is bottom (type of {@code null}).
3537 *
3538 * @param bound the lower bound
3539 * @param formal the formal type parameter that will be
3540 * substituted by the wildcard
3541 */
3542 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
3543 if (bound.tag == BOT) {
3544 return new WildcardType(syms.objectType,
3545 BoundKind.UNBOUND,
3546 syms.boundClass,
3547 formal);
3548 } else {
3549 return new WildcardType(bound,
3550 BoundKind.SUPER,
3551 syms.boundClass,
3552 formal);
3553 }
3554 }
3556 /**
3557 * A wrapper for a type that allows use in sets.
3558 */
3559 class SingletonType {
3560 final Type t;
3561 SingletonType(Type t) {
3562 this.t = t;
3563 }
3564 public int hashCode() {
3565 return Types.hashCode(t);
3566 }
3567 public boolean equals(Object obj) {
3568 return (obj instanceof SingletonType) &&
3569 isSameType(t, ((SingletonType)obj).t);
3570 }
3571 public String toString() {
3572 return t.toString();
3573 }
3574 }
3575 // </editor-fold>
3577 // <editor-fold defaultstate="collapsed" desc="Visitors">
3578 /**
3579 * A default visitor for types. All visitor methods except
3580 * visitType are implemented by delegating to visitType. Concrete
3581 * subclasses must provide an implementation of visitType and can
3582 * override other methods as needed.
3583 *
3584 * @param <R> the return type of the operation implemented by this
3585 * visitor; use Void if no return type is needed.
3586 * @param <S> the type of the second argument (the first being the
3587 * type itself) of the operation implemented by this visitor; use
3588 * Void if a second argument is not needed.
3589 */
3590 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
3591 final public R visit(Type t, S s) { return t.accept(this, s); }
3592 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
3593 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
3594 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
3595 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
3596 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
3597 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
3598 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
3599 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
3600 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
3601 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
3602 }
3604 /**
3605 * A default visitor for symbols. All visitor methods except
3606 * visitSymbol are implemented by delegating to visitSymbol. Concrete
3607 * subclasses must provide an implementation of visitSymbol and can
3608 * override other methods as needed.
3609 *
3610 * @param <R> the return type of the operation implemented by this
3611 * visitor; use Void if no return type is needed.
3612 * @param <S> the type of the second argument (the first being the
3613 * symbol itself) of the operation implemented by this visitor; use
3614 * Void if a second argument is not needed.
3615 */
3616 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
3617 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
3618 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
3619 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
3620 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
3621 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
3622 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
3623 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
3624 }
3626 /**
3627 * A <em>simple</em> visitor for types. This visitor is simple as
3628 * captured wildcards, for-all types (generic methods), and
3629 * undetermined type variables (part of inference) are hidden.
3630 * Captured wildcards are hidden by treating them as type
3631 * variables and the rest are hidden by visiting their qtypes.
3632 *
3633 * @param <R> the return type of the operation implemented by this
3634 * visitor; use Void if no return type is needed.
3635 * @param <S> the type of the second argument (the first being the
3636 * type itself) of the operation implemented by this visitor; use
3637 * Void if a second argument is not needed.
3638 */
3639 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
3640 @Override
3641 public R visitCapturedType(CapturedType t, S s) {
3642 return visitTypeVar(t, s);
3643 }
3644 @Override
3645 public R visitForAll(ForAll t, S s) {
3646 return visit(t.qtype, s);
3647 }
3648 @Override
3649 public R visitUndetVar(UndetVar t, S s) {
3650 return visit(t.qtype, s);
3651 }
3652 }
3654 /**
3655 * A plain relation on types. That is a 2-ary function on the
3656 * form Type × Type → Boolean.
3657 * <!-- In plain text: Type x Type -> Boolean -->
3658 */
3659 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
3661 /**
3662 * A convenience visitor for implementing operations that only
3663 * require one argument (the type itself), that is, unary
3664 * operations.
3665 *
3666 * @param <R> the return type of the operation implemented by this
3667 * visitor; use Void if no return type is needed.
3668 */
3669 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
3670 final public R visit(Type t) { return t.accept(this, null); }
3671 }
3673 /**
3674 * A visitor for implementing a mapping from types to types. The
3675 * default behavior of this class is to implement the identity
3676 * mapping (mapping a type to itself). This can be overridden in
3677 * subclasses.
3678 *
3679 * @param <S> the type of the second argument (the first being the
3680 * type itself) of this mapping; use Void if a second argument is
3681 * not needed.
3682 */
3683 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
3684 final public Type visit(Type t) { return t.accept(this, null); }
3685 public Type visitType(Type t, S s) { return t; }
3686 }
3687 // </editor-fold>
3690 // <editor-fold defaultstate="collapsed" desc="Annotation support">
3692 public RetentionPolicy getRetention(Attribute.Compound a) {
3693 RetentionPolicy vis = RetentionPolicy.CLASS; // the default
3694 Attribute.Compound c = a.type.tsym.attribute(syms.retentionType.tsym);
3695 if (c != null) {
3696 Attribute value = c.member(names.value);
3697 if (value != null && value instanceof Attribute.Enum) {
3698 Name levelName = ((Attribute.Enum)value).value.name;
3699 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
3700 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
3701 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
3702 else ;// /* fail soft */ throw new AssertionError(levelName);
3703 }
3704 }
3705 return vis;
3706 }
3707 // </editor-fold>
3708 }
