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src/share/classes/com/sun/tools/javac/code/Types.java@8eafba4f61be
src/share/classes/com/sun/tools/javac/code/Types.java
Thu, 09 Oct 2008 16:07:38 +0100
- author
- mcimadamore
- date
- Thu, 09 Oct 2008 16:07:38 +0100
- changeset 136
- 8eafba4f61be
- parent 134
- 8c098cf64ab5
- child 138
- d766e40e49d6
- permissions
- -rw-r--r--
6406133: JCDiagnostic.getMessage ignores locale argument
Summary: Compiler API should take into account locale settings
Reviewed-by: jjg
1 /*
2 * Copyright 2003-2008 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
26 package com.sun.tools.javac.code;
28 import java.util.*;
30 import com.sun.tools.javac.util.*;
31 import com.sun.tools.javac.util.List;
33 import com.sun.tools.javac.jvm.ClassReader;
34 import com.sun.tools.javac.comp.Check;
36 import static com.sun.tools.javac.code.Type.*;
37 import static com.sun.tools.javac.code.TypeTags.*;
38 import static com.sun.tools.javac.code.Symbol.*;
39 import static com.sun.tools.javac.code.Flags.*;
40 import static com.sun.tools.javac.code.BoundKind.*;
41 import static com.sun.tools.javac.util.ListBuffer.lb;
43 /**
44 * Utility class containing various operations on types.
45 *
46 * <p>Unless other names are more illustrative, the following naming
47 * conventions should be observed in this file:
48 *
49 * <dl>
50 * <dt>t</dt>
51 * <dd>If the first argument to an operation is a type, it should be named t.</dd>
52 * <dt>s</dt>
53 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
54 * <dt>ts</dt>
55 * <dd>If an operations takes a list of types, the first should be named ts.</dd>
56 * <dt>ss</dt>
57 * <dd>A second list of types should be named ss.</dd>
58 * </dl>
59 *
60 * <p><b>This is NOT part of any API supported by Sun Microsystems.
61 * If you write code that depends on this, you do so at your own risk.
62 * This code and its internal interfaces are subject to change or
63 * deletion without notice.</b>
64 */
65 public class Types {
66 protected static final Context.Key<Types> typesKey =
67 new Context.Key<Types>();
69 final Symtab syms;
70 final JavacMessages messages;
71 final Names names;
72 final boolean allowBoxing;
73 final ClassReader reader;
74 final Source source;
75 final Check chk;
76 List<Warner> warnStack = List.nil();
77 final Name capturedName;
79 // <editor-fold defaultstate="collapsed" desc="Instantiating">
80 public static Types instance(Context context) {
81 Types instance = context.get(typesKey);
82 if (instance == null)
83 instance = new Types(context);
84 return instance;
85 }
87 protected Types(Context context) {
88 context.put(typesKey, this);
89 syms = Symtab.instance(context);
90 names = Names.instance(context);
91 allowBoxing = Source.instance(context).allowBoxing();
92 reader = ClassReader.instance(context);
93 source = Source.instance(context);
94 chk = Check.instance(context);
95 capturedName = names.fromString("<captured wildcard>");
96 messages = JavacMessages.instance(context);
97 }
98 // </editor-fold>
100 // <editor-fold defaultstate="collapsed" desc="upperBound">
101 /**
102 * The "rvalue conversion".<br>
103 * The upper bound of most types is the type
104 * itself. Wildcards, on the other hand have upper
105 * and lower bounds.
106 * @param t a type
107 * @return the upper bound of the given type
108 */
109 public Type upperBound(Type t) {
110 return upperBound.visit(t);
111 }
112 // where
113 private final MapVisitor<Void> upperBound = new MapVisitor<Void>() {
115 @Override
116 public Type visitWildcardType(WildcardType t, Void ignored) {
117 if (t.isSuperBound())
118 return t.bound == null ? syms.objectType : t.bound.bound;
119 else
120 return visit(t.type);
121 }
123 @Override
124 public Type visitCapturedType(CapturedType t, Void ignored) {
125 return visit(t.bound);
126 }
127 };
128 // </editor-fold>
130 // <editor-fold defaultstate="collapsed" desc="lowerBound">
131 /**
132 * The "lvalue conversion".<br>
133 * The lower bound of most types is the type
134 * itself. Wildcards, on the other hand have upper
135 * and lower bounds.
136 * @param t a type
137 * @return the lower bound of the given type
138 */
139 public Type lowerBound(Type t) {
140 return lowerBound.visit(t);
141 }
142 // where
143 private final MapVisitor<Void> lowerBound = new MapVisitor<Void>() {
145 @Override
146 public Type visitWildcardType(WildcardType t, Void ignored) {
147 return t.isExtendsBound() ? syms.botType : visit(t.type);
148 }
150 @Override
151 public Type visitCapturedType(CapturedType t, Void ignored) {
152 return visit(t.getLowerBound());
153 }
154 };
155 // </editor-fold>
157 // <editor-fold defaultstate="collapsed" desc="isUnbounded">
158 /**
159 * Checks that all the arguments to a class are unbounded
160 * wildcards or something else that doesn't make any restrictions
161 * on the arguments. If a class isUnbounded, a raw super- or
162 * subclass can be cast to it without a warning.
163 * @param t a type
164 * @return true iff the given type is unbounded or raw
165 */
166 public boolean isUnbounded(Type t) {
167 return isUnbounded.visit(t);
168 }
169 // where
170 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
172 public Boolean visitType(Type t, Void ignored) {
173 return true;
174 }
176 @Override
177 public Boolean visitClassType(ClassType t, Void ignored) {
178 List<Type> parms = t.tsym.type.allparams();
179 List<Type> args = t.allparams();
180 while (parms.nonEmpty()) {
181 WildcardType unb = new WildcardType(syms.objectType,
182 BoundKind.UNBOUND,
183 syms.boundClass,
184 (TypeVar)parms.head);
185 if (!containsType(args.head, unb))
186 return false;
187 parms = parms.tail;
188 args = args.tail;
189 }
190 return true;
191 }
192 };
193 // </editor-fold>
195 // <editor-fold defaultstate="collapsed" desc="asSub">
196 /**
197 * Return the least specific subtype of t that starts with symbol
198 * sym. If none exists, return null. The least specific subtype
199 * is determined as follows:
200 *
201 * <p>If there is exactly one parameterized instance of sym that is a
202 * subtype of t, that parameterized instance is returned.<br>
203 * Otherwise, if the plain type or raw type `sym' is a subtype of
204 * type t, the type `sym' itself is returned. Otherwise, null is
205 * returned.
206 */
207 public Type asSub(Type t, Symbol sym) {
208 return asSub.visit(t, sym);
209 }
210 // where
211 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
213 public Type visitType(Type t, Symbol sym) {
214 return null;
215 }
217 @Override
218 public Type visitClassType(ClassType t, Symbol sym) {
219 if (t.tsym == sym)
220 return t;
221 Type base = asSuper(sym.type, t.tsym);
222 if (base == null)
223 return null;
224 ListBuffer<Type> from = new ListBuffer<Type>();
225 ListBuffer<Type> to = new ListBuffer<Type>();
226 try {
227 adapt(base, t, from, to);
228 } catch (AdaptFailure ex) {
229 return null;
230 }
231 Type res = subst(sym.type, from.toList(), to.toList());
232 if (!isSubtype(res, t))
233 return null;
234 ListBuffer<Type> openVars = new ListBuffer<Type>();
235 for (List<Type> l = sym.type.allparams();
236 l.nonEmpty(); l = l.tail)
237 if (res.contains(l.head) && !t.contains(l.head))
238 openVars.append(l.head);
239 if (openVars.nonEmpty()) {
240 if (t.isRaw()) {
241 // The subtype of a raw type is raw
242 res = erasure(res);
243 } else {
244 // Unbound type arguments default to ?
245 List<Type> opens = openVars.toList();
246 ListBuffer<Type> qs = new ListBuffer<Type>();
247 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
248 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head));
249 }
250 res = subst(res, opens, qs.toList());
251 }
252 }
253 return res;
254 }
256 @Override
257 public Type visitErrorType(ErrorType t, Symbol sym) {
258 return t;
259 }
260 };
261 // </editor-fold>
263 // <editor-fold defaultstate="collapsed" desc="isConvertible">
264 /**
265 * Is t a subtype of or convertiable via boxing/unboxing
266 * convertions to s?
267 */
268 public boolean isConvertible(Type t, Type s, Warner warn) {
269 boolean tPrimitive = t.isPrimitive();
270 boolean sPrimitive = s.isPrimitive();
271 if (tPrimitive == sPrimitive)
272 return isSubtypeUnchecked(t, s, warn);
273 if (!allowBoxing) return false;
274 return tPrimitive
275 ? isSubtype(boxedClass(t).type, s)
276 : isSubtype(unboxedType(t), s);
277 }
279 /**
280 * Is t a subtype of or convertiable via boxing/unboxing
281 * convertions to s?
282 */
283 public boolean isConvertible(Type t, Type s) {
284 return isConvertible(t, s, Warner.noWarnings);
285 }
286 // </editor-fold>
288 // <editor-fold defaultstate="collapsed" desc="isSubtype">
289 /**
290 * Is t an unchecked subtype of s?
291 */
292 public boolean isSubtypeUnchecked(Type t, Type s) {
293 return isSubtypeUnchecked(t, s, Warner.noWarnings);
294 }
295 /**
296 * Is t an unchecked subtype of s?
297 */
298 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
299 if (t.tag == ARRAY && s.tag == ARRAY) {
300 return (((ArrayType)t).elemtype.tag <= lastBaseTag)
301 ? isSameType(elemtype(t), elemtype(s))
302 : isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
303 } else if (isSubtype(t, s)) {
304 return true;
305 }
306 else if (t.tag == TYPEVAR) {
307 return isSubtypeUnchecked(t.getUpperBound(), s, warn);
308 }
309 else if (s.tag == UNDETVAR) {
310 UndetVar uv = (UndetVar)s;
311 if (uv.inst != null)
312 return isSubtypeUnchecked(t, uv.inst, warn);
313 }
314 else if (!s.isRaw()) {
315 Type t2 = asSuper(t, s.tsym);
316 if (t2 != null && t2.isRaw()) {
317 if (isReifiable(s))
318 warn.silentUnchecked();
319 else
320 warn.warnUnchecked();
321 return true;
322 }
323 }
324 return false;
325 }
327 /**
328 * Is t a subtype of s?<br>
329 * (not defined for Method and ForAll types)
330 */
331 final public boolean isSubtype(Type t, Type s) {
332 return isSubtype(t, s, true);
333 }
334 final public boolean isSubtypeNoCapture(Type t, Type s) {
335 return isSubtype(t, s, false);
336 }
337 public boolean isSubtype(Type t, Type s, boolean capture) {
338 if (t == s)
339 return true;
341 if (s.tag >= firstPartialTag)
342 return isSuperType(s, t);
344 Type lower = lowerBound(s);
345 if (s != lower)
346 return isSubtype(capture ? capture(t) : t, lower, false);
348 return isSubtype.visit(capture ? capture(t) : t, s);
349 }
350 // where
351 private TypeRelation isSubtype = new TypeRelation()
352 {
353 public Boolean visitType(Type t, Type s) {
354 switch (t.tag) {
355 case BYTE: case CHAR:
356 return (t.tag == s.tag ||
357 t.tag + 2 <= s.tag && s.tag <= DOUBLE);
358 case SHORT: case INT: case LONG: case FLOAT: case DOUBLE:
359 return t.tag <= s.tag && s.tag <= DOUBLE;
360 case BOOLEAN: case VOID:
361 return t.tag == s.tag;
362 case TYPEVAR:
363 return isSubtypeNoCapture(t.getUpperBound(), s);
364 case BOT:
365 return
366 s.tag == BOT || s.tag == CLASS ||
367 s.tag == ARRAY || s.tag == TYPEVAR;
368 case NONE:
369 return false;
370 default:
371 throw new AssertionError("isSubtype " + t.tag);
372 }
373 }
375 private Set<TypePair> cache = new HashSet<TypePair>();
377 private boolean containsTypeRecursive(Type t, Type s) {
378 TypePair pair = new TypePair(t, s);
379 if (cache.add(pair)) {
380 try {
381 return containsType(t.getTypeArguments(),
382 s.getTypeArguments());
383 } finally {
384 cache.remove(pair);
385 }
386 } else {
387 return containsType(t.getTypeArguments(),
388 rewriteSupers(s).getTypeArguments());
389 }
390 }
392 private Type rewriteSupers(Type t) {
393 if (!t.isParameterized())
394 return t;
395 ListBuffer<Type> from = lb();
396 ListBuffer<Type> to = lb();
397 adaptSelf(t, from, to);
398 if (from.isEmpty())
399 return t;
400 ListBuffer<Type> rewrite = lb();
401 boolean changed = false;
402 for (Type orig : to.toList()) {
403 Type s = rewriteSupers(orig);
404 if (s.isSuperBound() && !s.isExtendsBound()) {
405 s = new WildcardType(syms.objectType,
406 BoundKind.UNBOUND,
407 syms.boundClass);
408 changed = true;
409 } else if (s != orig) {
410 s = new WildcardType(upperBound(s),
411 BoundKind.EXTENDS,
412 syms.boundClass);
413 changed = true;
414 }
415 rewrite.append(s);
416 }
417 if (changed)
418 return subst(t.tsym.type, from.toList(), rewrite.toList());
419 else
420 return t;
421 }
423 @Override
424 public Boolean visitClassType(ClassType t, Type s) {
425 Type sup = asSuper(t, s.tsym);
426 return sup != null
427 && sup.tsym == s.tsym
428 // You're not allowed to write
429 // Vector<Object> vec = new Vector<String>();
430 // But with wildcards you can write
431 // Vector<? extends Object> vec = new Vector<String>();
432 // which means that subtype checking must be done
433 // here instead of same-type checking (via containsType).
434 && (!s.isParameterized() || containsTypeRecursive(s, sup))
435 && isSubtypeNoCapture(sup.getEnclosingType(),
436 s.getEnclosingType());
437 }
439 @Override
440 public Boolean visitArrayType(ArrayType t, Type s) {
441 if (s.tag == ARRAY) {
442 if (t.elemtype.tag <= lastBaseTag)
443 return isSameType(t.elemtype, elemtype(s));
444 else
445 return isSubtypeNoCapture(t.elemtype, elemtype(s));
446 }
448 if (s.tag == CLASS) {
449 Name sname = s.tsym.getQualifiedName();
450 return sname == names.java_lang_Object
451 || sname == names.java_lang_Cloneable
452 || sname == names.java_io_Serializable;
453 }
455 return false;
456 }
458 @Override
459 public Boolean visitUndetVar(UndetVar t, Type s) {
460 //todo: test against origin needed? or replace with substitution?
461 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
462 return true;
464 if (t.inst != null)
465 return isSubtypeNoCapture(t.inst, s); // TODO: ", warn"?
467 t.hibounds = t.hibounds.prepend(s);
468 return true;
469 }
471 @Override
472 public Boolean visitErrorType(ErrorType t, Type s) {
473 return true;
474 }
475 };
477 /**
478 * Is t a subtype of every type in given list `ts'?<br>
479 * (not defined for Method and ForAll types)<br>
480 * Allows unchecked conversions.
481 */
482 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
483 for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
484 if (!isSubtypeUnchecked(t, l.head, warn))
485 return false;
486 return true;
487 }
489 /**
490 * Are corresponding elements of ts subtypes of ss? If lists are
491 * of different length, return false.
492 */
493 public boolean isSubtypes(List<Type> ts, List<Type> ss) {
494 while (ts.tail != null && ss.tail != null
495 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
496 isSubtype(ts.head, ss.head)) {
497 ts = ts.tail;
498 ss = ss.tail;
499 }
500 return ts.tail == null && ss.tail == null;
501 /*inlined: ts.isEmpty() && ss.isEmpty();*/
502 }
504 /**
505 * Are corresponding elements of ts subtypes of ss, allowing
506 * unchecked conversions? If lists are of different length,
507 * return false.
508 **/
509 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
510 while (ts.tail != null && ss.tail != null
511 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
512 isSubtypeUnchecked(ts.head, ss.head, warn)) {
513 ts = ts.tail;
514 ss = ss.tail;
515 }
516 return ts.tail == null && ss.tail == null;
517 /*inlined: ts.isEmpty() && ss.isEmpty();*/
518 }
519 // </editor-fold>
521 // <editor-fold defaultstate="collapsed" desc="isSuperType">
522 /**
523 * Is t a supertype of s?
524 */
525 public boolean isSuperType(Type t, Type s) {
526 switch (t.tag) {
527 case ERROR:
528 return true;
529 case UNDETVAR: {
530 UndetVar undet = (UndetVar)t;
531 if (t == s ||
532 undet.qtype == s ||
533 s.tag == ERROR ||
534 s.tag == BOT) return true;
535 if (undet.inst != null)
536 return isSubtype(s, undet.inst);
537 undet.lobounds = undet.lobounds.prepend(s);
538 return true;
539 }
540 default:
541 return isSubtype(s, t);
542 }
543 }
544 // </editor-fold>
546 // <editor-fold defaultstate="collapsed" desc="isSameType">
547 /**
548 * Are corresponding elements of the lists the same type? If
549 * lists are of different length, return false.
550 */
551 public boolean isSameTypes(List<Type> ts, List<Type> ss) {
552 while (ts.tail != null && ss.tail != null
553 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
554 isSameType(ts.head, ss.head)) {
555 ts = ts.tail;
556 ss = ss.tail;
557 }
558 return ts.tail == null && ss.tail == null;
559 /*inlined: ts.isEmpty() && ss.isEmpty();*/
560 }
562 /**
563 * Is t the same type as s?
564 */
565 public boolean isSameType(Type t, Type s) {
566 return isSameType.visit(t, s);
567 }
568 // where
569 private TypeRelation isSameType = new TypeRelation() {
571 public Boolean visitType(Type t, Type s) {
572 if (t == s)
573 return true;
575 if (s.tag >= firstPartialTag)
576 return visit(s, t);
578 switch (t.tag) {
579 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
580 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
581 return t.tag == s.tag;
582 case TYPEVAR:
583 return s.isSuperBound()
584 && !s.isExtendsBound()
585 && visit(t, upperBound(s));
586 default:
587 throw new AssertionError("isSameType " + t.tag);
588 }
589 }
591 @Override
592 public Boolean visitWildcardType(WildcardType t, Type s) {
593 if (s.tag >= firstPartialTag)
594 return visit(s, t);
595 else
596 return false;
597 }
599 @Override
600 public Boolean visitClassType(ClassType t, Type s) {
601 if (t == s)
602 return true;
604 if (s.tag >= firstPartialTag)
605 return visit(s, t);
607 if (s.isSuperBound() && !s.isExtendsBound())
608 return visit(t, upperBound(s)) && visit(t, lowerBound(s));
610 if (t.isCompound() && s.isCompound()) {
611 if (!visit(supertype(t), supertype(s)))
612 return false;
614 HashSet<SingletonType> set = new HashSet<SingletonType>();
615 for (Type x : interfaces(t))
616 set.add(new SingletonType(x));
617 for (Type x : interfaces(s)) {
618 if (!set.remove(new SingletonType(x)))
619 return false;
620 }
621 return (set.size() == 0);
622 }
623 return t.tsym == s.tsym
624 && visit(t.getEnclosingType(), s.getEnclosingType())
625 && containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
626 }
628 @Override
629 public Boolean visitArrayType(ArrayType t, Type s) {
630 if (t == s)
631 return true;
633 if (s.tag >= firstPartialTag)
634 return visit(s, t);
636 return s.tag == ARRAY
637 && containsTypeEquivalent(t.elemtype, elemtype(s));
638 }
640 @Override
641 public Boolean visitMethodType(MethodType t, Type s) {
642 // isSameType for methods does not take thrown
643 // exceptions into account!
644 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
645 }
647 @Override
648 public Boolean visitPackageType(PackageType t, Type s) {
649 return t == s;
650 }
652 @Override
653 public Boolean visitForAll(ForAll t, Type s) {
654 if (s.tag != FORALL)
655 return false;
657 ForAll forAll = (ForAll)s;
658 return hasSameBounds(t, forAll)
659 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
660 }
662 @Override
663 public Boolean visitUndetVar(UndetVar t, Type s) {
664 if (s.tag == WILDCARD)
665 // FIXME, this might be leftovers from before capture conversion
666 return false;
668 if (t == s || t.qtype == s || s.tag == ERROR || s.tag == UNKNOWN)
669 return true;
671 if (t.inst != null)
672 return visit(t.inst, s);
674 t.inst = fromUnknownFun.apply(s);
675 for (List<Type> l = t.lobounds; l.nonEmpty(); l = l.tail) {
676 if (!isSubtype(l.head, t.inst))
677 return false;
678 }
679 for (List<Type> l = t.hibounds; l.nonEmpty(); l = l.tail) {
680 if (!isSubtype(t.inst, l.head))
681 return false;
682 }
683 return true;
684 }
686 @Override
687 public Boolean visitErrorType(ErrorType t, Type s) {
688 return true;
689 }
690 };
691 // </editor-fold>
693 // <editor-fold defaultstate="collapsed" desc="fromUnknownFun">
694 /**
695 * A mapping that turns all unknown types in this type to fresh
696 * unknown variables.
697 */
698 public Mapping fromUnknownFun = new Mapping("fromUnknownFun") {
699 public Type apply(Type t) {
700 if (t.tag == UNKNOWN) return new UndetVar(t);
701 else return t.map(this);
702 }
703 };
704 // </editor-fold>
706 // <editor-fold defaultstate="collapsed" desc="Contains Type">
707 public boolean containedBy(Type t, Type s) {
708 switch (t.tag) {
709 case UNDETVAR:
710 if (s.tag == WILDCARD) {
711 UndetVar undetvar = (UndetVar)t;
713 // Because of wildcard capture, s must be on the left
714 // hand side of an assignment. Furthermore, t is an
715 // underconstrained type variable, for example, one
716 // that is only used in the return type of a method.
717 // If the type variable is truly underconstrained, it
718 // cannot have any low bounds:
719 assert undetvar.lobounds.isEmpty() : undetvar;
721 undetvar.inst = glb(upperBound(s), undetvar.inst);
722 return true;
723 } else {
724 return isSameType(t, s);
725 }
726 case ERROR:
727 return true;
728 default:
729 return containsType(s, t);
730 }
731 }
733 boolean containsType(List<Type> ts, List<Type> ss) {
734 while (ts.nonEmpty() && ss.nonEmpty()
735 && containsType(ts.head, ss.head)) {
736 ts = ts.tail;
737 ss = ss.tail;
738 }
739 return ts.isEmpty() && ss.isEmpty();
740 }
742 /**
743 * Check if t contains s.
744 *
745 * <p>T contains S if:
746 *
747 * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
748 *
749 * <p>This relation is only used by ClassType.isSubtype(), that
750 * is,
751 *
752 * <p>{@code C<S> <: C<T> if T contains S.}
753 *
754 * <p>Because of F-bounds, this relation can lead to infinite
755 * recursion. Thus we must somehow break that recursion. Notice
756 * that containsType() is only called from ClassType.isSubtype().
757 * Since the arguments have already been checked against their
758 * bounds, we know:
759 *
760 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
761 *
762 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
763 *
764 * @param t a type
765 * @param s a type
766 */
767 public boolean containsType(Type t, Type s) {
768 return containsType.visit(t, s);
769 }
770 // where
771 private TypeRelation containsType = new TypeRelation() {
773 private Type U(Type t) {
774 while (t.tag == WILDCARD) {
775 WildcardType w = (WildcardType)t;
776 if (w.isSuperBound())
777 return w.bound == null ? syms.objectType : w.bound.bound;
778 else
779 t = w.type;
780 }
781 return t;
782 }
784 private Type L(Type t) {
785 while (t.tag == WILDCARD) {
786 WildcardType w = (WildcardType)t;
787 if (w.isExtendsBound())
788 return syms.botType;
789 else
790 t = w.type;
791 }
792 return t;
793 }
795 public Boolean visitType(Type t, Type s) {
796 if (s.tag >= firstPartialTag)
797 return containedBy(s, t);
798 else
799 return isSameType(t, s);
800 }
802 void debugContainsType(WildcardType t, Type s) {
803 System.err.println();
804 System.err.format(" does %s contain %s?%n", t, s);
805 System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
806 upperBound(s), s, t, U(t),
807 t.isSuperBound()
808 || isSubtypeNoCapture(upperBound(s), U(t)));
809 System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
810 L(t), t, s, lowerBound(s),
811 t.isExtendsBound()
812 || isSubtypeNoCapture(L(t), lowerBound(s)));
813 System.err.println();
814 }
816 @Override
817 public Boolean visitWildcardType(WildcardType t, Type s) {
818 if (s.tag >= firstPartialTag)
819 return containedBy(s, t);
820 else {
821 // debugContainsType(t, s);
822 return isSameWildcard(t, s)
823 || isCaptureOf(s, t)
824 || ((t.isExtendsBound() || isSubtypeNoCapture(L(t), lowerBound(s))) &&
825 (t.isSuperBound() || isSubtypeNoCapture(upperBound(s), U(t))));
826 }
827 }
829 @Override
830 public Boolean visitUndetVar(UndetVar t, Type s) {
831 if (s.tag != WILDCARD)
832 return isSameType(t, s);
833 else
834 return false;
835 }
837 @Override
838 public Boolean visitErrorType(ErrorType t, Type s) {
839 return true;
840 }
841 };
843 public boolean isCaptureOf(Type s, WildcardType t) {
844 if (s.tag != TYPEVAR || !((TypeVar)s).isCaptured())
845 return false;
846 return isSameWildcard(t, ((CapturedType)s).wildcard);
847 }
849 public boolean isSameWildcard(WildcardType t, Type s) {
850 if (s.tag != WILDCARD)
851 return false;
852 WildcardType w = (WildcardType)s;
853 return w.kind == t.kind && w.type == t.type;
854 }
856 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
857 while (ts.nonEmpty() && ss.nonEmpty()
858 && containsTypeEquivalent(ts.head, ss.head)) {
859 ts = ts.tail;
860 ss = ss.tail;
861 }
862 return ts.isEmpty() && ss.isEmpty();
863 }
864 // </editor-fold>
866 // <editor-fold defaultstate="collapsed" desc="isCastable">
867 public boolean isCastable(Type t, Type s) {
868 return isCastable(t, s, Warner.noWarnings);
869 }
871 /**
872 * Is t is castable to s?<br>
873 * s is assumed to be an erased type.<br>
874 * (not defined for Method and ForAll types).
875 */
876 public boolean isCastable(Type t, Type s, Warner warn) {
877 if (t == s)
878 return true;
880 if (t.isPrimitive() != s.isPrimitive())
881 return allowBoxing && isConvertible(t, s, warn);
883 if (warn != warnStack.head) {
884 try {
885 warnStack = warnStack.prepend(warn);
886 return isCastable.visit(t, s);
887 } finally {
888 warnStack = warnStack.tail;
889 }
890 } else {
891 return isCastable.visit(t, s);
892 }
893 }
894 // where
895 private TypeRelation isCastable = new TypeRelation() {
897 public Boolean visitType(Type t, Type s) {
898 if (s.tag == ERROR)
899 return true;
901 switch (t.tag) {
902 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
903 case DOUBLE:
904 return s.tag <= DOUBLE;
905 case BOOLEAN:
906 return s.tag == BOOLEAN;
907 case VOID:
908 return false;
909 case BOT:
910 return isSubtype(t, s);
911 default:
912 throw new AssertionError();
913 }
914 }
916 @Override
917 public Boolean visitWildcardType(WildcardType t, Type s) {
918 return isCastable(upperBound(t), s, warnStack.head);
919 }
921 @Override
922 public Boolean visitClassType(ClassType t, Type s) {
923 if (s.tag == ERROR || s.tag == BOT)
924 return true;
926 if (s.tag == TYPEVAR) {
927 if (isCastable(s.getUpperBound(), t, Warner.noWarnings)) {
928 warnStack.head.warnUnchecked();
929 return true;
930 } else {
931 return false;
932 }
933 }
935 if (t.isCompound()) {
936 if (!visit(supertype(t), s))
937 return false;
938 for (Type intf : interfaces(t)) {
939 if (!visit(intf, s))
940 return false;
941 }
942 return true;
943 }
945 if (s.isCompound()) {
946 // call recursively to reuse the above code
947 return visitClassType((ClassType)s, t);
948 }
950 if (s.tag == CLASS || s.tag == ARRAY) {
951 boolean upcast;
952 if ((upcast = isSubtype(erasure(t), erasure(s)))
953 || isSubtype(erasure(s), erasure(t))) {
954 if (!upcast && s.tag == ARRAY) {
955 if (!isReifiable(s))
956 warnStack.head.warnUnchecked();
957 return true;
958 } else if (s.isRaw()) {
959 return true;
960 } else if (t.isRaw()) {
961 if (!isUnbounded(s))
962 warnStack.head.warnUnchecked();
963 return true;
964 }
965 // Assume |a| <: |b|
966 final Type a = upcast ? t : s;
967 final Type b = upcast ? s : t;
968 final boolean HIGH = true;
969 final boolean LOW = false;
970 final boolean DONT_REWRITE_TYPEVARS = false;
971 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
972 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
973 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
974 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
975 Type lowSub = asSub(bLow, aLow.tsym);
976 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
977 if (highSub == null) {
978 final boolean REWRITE_TYPEVARS = true;
979 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
980 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
981 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
982 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
983 lowSub = asSub(bLow, aLow.tsym);
984 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
985 }
986 if (highSub != null) {
987 assert a.tsym == highSub.tsym && a.tsym == lowSub.tsym
988 : a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym;
989 if (!disjointTypes(aHigh.getTypeArguments(), highSub.getTypeArguments())
990 && !disjointTypes(aHigh.getTypeArguments(), lowSub.getTypeArguments())
991 && !disjointTypes(aLow.getTypeArguments(), highSub.getTypeArguments())
992 && !disjointTypes(aLow.getTypeArguments(), lowSub.getTypeArguments())) {
993 if (upcast ? giveWarning(a, highSub) || giveWarning(a, lowSub)
994 : giveWarning(highSub, a) || giveWarning(lowSub, a))
995 warnStack.head.warnUnchecked();
996 return true;
997 }
998 }
999 if (isReifiable(s))
1000 return isSubtypeUnchecked(a, b);
1001 else
1002 return isSubtypeUnchecked(a, b, warnStack.head);
1003 }
1005 // Sidecast
1006 if (s.tag == CLASS) {
1007 if ((s.tsym.flags() & INTERFACE) != 0) {
1008 return ((t.tsym.flags() & FINAL) == 0)
1009 ? sideCast(t, s, warnStack.head)
1010 : sideCastFinal(t, s, warnStack.head);
1011 } else if ((t.tsym.flags() & INTERFACE) != 0) {
1012 return ((s.tsym.flags() & FINAL) == 0)
1013 ? sideCast(t, s, warnStack.head)
1014 : sideCastFinal(t, s, warnStack.head);
1015 } else {
1016 // unrelated class types
1017 return false;
1018 }
1019 }
1020 }
1021 return false;
1022 }
1024 @Override
1025 public Boolean visitArrayType(ArrayType t, Type s) {
1026 switch (s.tag) {
1027 case ERROR:
1028 case BOT:
1029 return true;
1030 case TYPEVAR:
1031 if (isCastable(s, t, Warner.noWarnings)) {
1032 warnStack.head.warnUnchecked();
1033 return true;
1034 } else {
1035 return false;
1036 }
1037 case CLASS:
1038 return isSubtype(t, s);
1039 case ARRAY:
1040 if (elemtype(t).tag <= lastBaseTag) {
1041 return elemtype(t).tag == elemtype(s).tag;
1042 } else {
1043 return visit(elemtype(t), elemtype(s));
1044 }
1045 default:
1046 return false;
1047 }
1048 }
1050 @Override
1051 public Boolean visitTypeVar(TypeVar t, Type s) {
1052 switch (s.tag) {
1053 case ERROR:
1054 case BOT:
1055 return true;
1056 case TYPEVAR:
1057 if (isSubtype(t, s)) {
1058 return true;
1059 } else if (isCastable(t.bound, s, Warner.noWarnings)) {
1060 warnStack.head.warnUnchecked();
1061 return true;
1062 } else {
1063 return false;
1064 }
1065 default:
1066 return isCastable(t.bound, s, warnStack.head);
1067 }
1068 }
1070 @Override
1071 public Boolean visitErrorType(ErrorType t, Type s) {
1072 return true;
1073 }
1074 };
1075 // </editor-fold>
1077 // <editor-fold defaultstate="collapsed" desc="disjointTypes">
1078 public boolean disjointTypes(List<Type> ts, List<Type> ss) {
1079 while (ts.tail != null && ss.tail != null) {
1080 if (disjointType(ts.head, ss.head)) return true;
1081 ts = ts.tail;
1082 ss = ss.tail;
1083 }
1084 return false;
1085 }
1087 /**
1088 * Two types or wildcards are considered disjoint if it can be
1089 * proven that no type can be contained in both. It is
1090 * conservative in that it is allowed to say that two types are
1091 * not disjoint, even though they actually are.
1092 *
1093 * The type C<X> is castable to C<Y> exactly if X and Y are not
1094 * disjoint.
1095 */
1096 public boolean disjointType(Type t, Type s) {
1097 return disjointType.visit(t, s);
1098 }
1099 // where
1100 private TypeRelation disjointType = new TypeRelation() {
1102 private Set<TypePair> cache = new HashSet<TypePair>();
1104 public Boolean visitType(Type t, Type s) {
1105 if (s.tag == WILDCARD)
1106 return visit(s, t);
1107 else
1108 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
1109 }
1111 private boolean isCastableRecursive(Type t, Type s) {
1112 TypePair pair = new TypePair(t, s);
1113 if (cache.add(pair)) {
1114 try {
1115 return Types.this.isCastable(t, s);
1116 } finally {
1117 cache.remove(pair);
1118 }
1119 } else {
1120 return true;
1121 }
1122 }
1124 private boolean notSoftSubtypeRecursive(Type t, Type s) {
1125 TypePair pair = new TypePair(t, s);
1126 if (cache.add(pair)) {
1127 try {
1128 return Types.this.notSoftSubtype(t, s);
1129 } finally {
1130 cache.remove(pair);
1131 }
1132 } else {
1133 return false;
1134 }
1135 }
1137 @Override
1138 public Boolean visitWildcardType(WildcardType t, Type s) {
1139 if (t.isUnbound())
1140 return false;
1142 if (s.tag != WILDCARD) {
1143 if (t.isExtendsBound())
1144 return notSoftSubtypeRecursive(s, t.type);
1145 else // isSuperBound()
1146 return notSoftSubtypeRecursive(t.type, s);
1147 }
1149 if (s.isUnbound())
1150 return false;
1152 if (t.isExtendsBound()) {
1153 if (s.isExtendsBound())
1154 return !isCastableRecursive(t.type, upperBound(s));
1155 else if (s.isSuperBound())
1156 return notSoftSubtypeRecursive(lowerBound(s), t.type);
1157 } else if (t.isSuperBound()) {
1158 if (s.isExtendsBound())
1159 return notSoftSubtypeRecursive(t.type, upperBound(s));
1160 }
1161 return false;
1162 }
1163 };
1164 // </editor-fold>
1166 // <editor-fold defaultstate="collapsed" desc="lowerBoundArgtypes">
1167 /**
1168 * Returns the lower bounds of the formals of a method.
1169 */
1170 public List<Type> lowerBoundArgtypes(Type t) {
1171 return map(t.getParameterTypes(), lowerBoundMapping);
1172 }
1173 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1174 public Type apply(Type t) {
1175 return lowerBound(t);
1176 }
1177 };
1178 // </editor-fold>
1180 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
1181 /**
1182 * This relation answers the question: is impossible that
1183 * something of type `t' can be a subtype of `s'? This is
1184 * different from the question "is `t' not a subtype of `s'?"
1185 * when type variables are involved: Integer is not a subtype of T
1186 * where <T extends Number> but it is not true that Integer cannot
1187 * possibly be a subtype of T.
1188 */
1189 public boolean notSoftSubtype(Type t, Type s) {
1190 if (t == s) return false;
1191 if (t.tag == TYPEVAR) {
1192 TypeVar tv = (TypeVar) t;
1193 if (s.tag == TYPEVAR)
1194 s = s.getUpperBound();
1195 return !isCastable(tv.bound,
1196 s,
1197 Warner.noWarnings);
1198 }
1199 if (s.tag != WILDCARD)
1200 s = upperBound(s);
1201 if (s.tag == TYPEVAR)
1202 s = s.getUpperBound();
1203 return !isSubtype(t, s);
1204 }
1205 // </editor-fold>
1207 // <editor-fold defaultstate="collapsed" desc="isReifiable">
1208 public boolean isReifiable(Type t) {
1209 return isReifiable.visit(t);
1210 }
1211 // where
1212 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
1214 public Boolean visitType(Type t, Void ignored) {
1215 return true;
1216 }
1218 @Override
1219 public Boolean visitClassType(ClassType t, Void ignored) {
1220 if (!t.isParameterized())
1221 return true;
1223 for (Type param : t.allparams()) {
1224 if (!param.isUnbound())
1225 return false;
1226 }
1227 return true;
1228 }
1230 @Override
1231 public Boolean visitArrayType(ArrayType t, Void ignored) {
1232 return visit(t.elemtype);
1233 }
1235 @Override
1236 public Boolean visitTypeVar(TypeVar t, Void ignored) {
1237 return false;
1238 }
1239 };
1240 // </editor-fold>
1242 // <editor-fold defaultstate="collapsed" desc="Array Utils">
1243 public boolean isArray(Type t) {
1244 while (t.tag == WILDCARD)
1245 t = upperBound(t);
1246 return t.tag == ARRAY;
1247 }
1249 /**
1250 * The element type of an array.
1251 */
1252 public Type elemtype(Type t) {
1253 switch (t.tag) {
1254 case WILDCARD:
1255 return elemtype(upperBound(t));
1256 case ARRAY:
1257 return ((ArrayType)t).elemtype;
1258 case FORALL:
1259 return elemtype(((ForAll)t).qtype);
1260 case ERROR:
1261 return t;
1262 default:
1263 return null;
1264 }
1265 }
1267 /**
1268 * Mapping to take element type of an arraytype
1269 */
1270 private Mapping elemTypeFun = new Mapping ("elemTypeFun") {
1271 public Type apply(Type t) { return elemtype(t); }
1272 };
1274 /**
1275 * The number of dimensions of an array type.
1276 */
1277 public int dimensions(Type t) {
1278 int result = 0;
1279 while (t.tag == ARRAY) {
1280 result++;
1281 t = elemtype(t);
1282 }
1283 return result;
1284 }
1285 // </editor-fold>
1287 // <editor-fold defaultstate="collapsed" desc="asSuper">
1288 /**
1289 * Return the (most specific) base type of t that starts with the
1290 * given symbol. If none exists, return null.
1291 *
1292 * @param t a type
1293 * @param sym a symbol
1294 */
1295 public Type asSuper(Type t, Symbol sym) {
1296 return asSuper.visit(t, sym);
1297 }
1298 // where
1299 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
1301 public Type visitType(Type t, Symbol sym) {
1302 return null;
1303 }
1305 @Override
1306 public Type visitClassType(ClassType t, Symbol sym) {
1307 if (t.tsym == sym)
1308 return t;
1310 Type st = supertype(t);
1311 if (st.tag == CLASS || st.tag == TYPEVAR || st.tag == ERROR) {
1312 Type x = asSuper(st, sym);
1313 if (x != null)
1314 return x;
1315 }
1316 if ((sym.flags() & INTERFACE) != 0) {
1317 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
1318 Type x = asSuper(l.head, sym);
1319 if (x != null)
1320 return x;
1321 }
1322 }
1323 return null;
1324 }
1326 @Override
1327 public Type visitArrayType(ArrayType t, Symbol sym) {
1328 return isSubtype(t, sym.type) ? sym.type : null;
1329 }
1331 @Override
1332 public Type visitTypeVar(TypeVar t, Symbol sym) {
1333 if (t.tsym == sym)
1334 return t;
1335 else
1336 return asSuper(t.bound, sym);
1337 }
1339 @Override
1340 public Type visitErrorType(ErrorType t, Symbol sym) {
1341 return t;
1342 }
1343 };
1345 /**
1346 * Return the base type of t or any of its outer types that starts
1347 * with the given symbol. If none exists, return null.
1348 *
1349 * @param t a type
1350 * @param sym a symbol
1351 */
1352 public Type asOuterSuper(Type t, Symbol sym) {
1353 switch (t.tag) {
1354 case CLASS:
1355 do {
1356 Type s = asSuper(t, sym);
1357 if (s != null) return s;
1358 t = t.getEnclosingType();
1359 } while (t.tag == CLASS);
1360 return null;
1361 case ARRAY:
1362 return isSubtype(t, sym.type) ? sym.type : null;
1363 case TYPEVAR:
1364 return asSuper(t, sym);
1365 case ERROR:
1366 return t;
1367 default:
1368 return null;
1369 }
1370 }
1372 /**
1373 * Return the base type of t or any of its enclosing types that
1374 * starts with the given symbol. If none exists, return null.
1375 *
1376 * @param t a type
1377 * @param sym a symbol
1378 */
1379 public Type asEnclosingSuper(Type t, Symbol sym) {
1380 switch (t.tag) {
1381 case CLASS:
1382 do {
1383 Type s = asSuper(t, sym);
1384 if (s != null) return s;
1385 Type outer = t.getEnclosingType();
1386 t = (outer.tag == CLASS) ? outer :
1387 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
1388 Type.noType;
1389 } while (t.tag == CLASS);
1390 return null;
1391 case ARRAY:
1392 return isSubtype(t, sym.type) ? sym.type : null;
1393 case TYPEVAR:
1394 return asSuper(t, sym);
1395 case ERROR:
1396 return t;
1397 default:
1398 return null;
1399 }
1400 }
1401 // </editor-fold>
1403 // <editor-fold defaultstate="collapsed" desc="memberType">
1404 /**
1405 * The type of given symbol, seen as a member of t.
1406 *
1407 * @param t a type
1408 * @param sym a symbol
1409 */
1410 public Type memberType(Type t, Symbol sym) {
1411 return (sym.flags() & STATIC) != 0
1412 ? sym.type
1413 : memberType.visit(t, sym);
1414 }
1415 // where
1416 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
1418 public Type visitType(Type t, Symbol sym) {
1419 return sym.type;
1420 }
1422 @Override
1423 public Type visitWildcardType(WildcardType t, Symbol sym) {
1424 return memberType(upperBound(t), sym);
1425 }
1427 @Override
1428 public Type visitClassType(ClassType t, Symbol sym) {
1429 Symbol owner = sym.owner;
1430 long flags = sym.flags();
1431 if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
1432 Type base = asOuterSuper(t, owner);
1433 //if t is an intersection type T = CT & I1 & I2 ... & In
1434 //its supertypes CT, I1, ... In might contain wildcards
1435 //so we need to go through capture conversion
1436 base = t.isCompound() ? capture(base) : base;
1437 if (base != null) {
1438 List<Type> ownerParams = owner.type.allparams();
1439 List<Type> baseParams = base.allparams();
1440 if (ownerParams.nonEmpty()) {
1441 if (baseParams.isEmpty()) {
1442 // then base is a raw type
1443 return erasure(sym.type);
1444 } else {
1445 return subst(sym.type, ownerParams, baseParams);
1446 }
1447 }
1448 }
1449 }
1450 return sym.type;
1451 }
1453 @Override
1454 public Type visitTypeVar(TypeVar t, Symbol sym) {
1455 return memberType(t.bound, sym);
1456 }
1458 @Override
1459 public Type visitErrorType(ErrorType t, Symbol sym) {
1460 return t;
1461 }
1462 };
1463 // </editor-fold>
1465 // <editor-fold defaultstate="collapsed" desc="isAssignable">
1466 public boolean isAssignable(Type t, Type s) {
1467 return isAssignable(t, s, Warner.noWarnings);
1468 }
1470 /**
1471 * Is t assignable to s?<br>
1472 * Equivalent to subtype except for constant values and raw
1473 * types.<br>
1474 * (not defined for Method and ForAll types)
1475 */
1476 public boolean isAssignable(Type t, Type s, Warner warn) {
1477 if (t.tag == ERROR)
1478 return true;
1479 if (t.tag <= INT && t.constValue() != null) {
1480 int value = ((Number)t.constValue()).intValue();
1481 switch (s.tag) {
1482 case BYTE:
1483 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
1484 return true;
1485 break;
1486 case CHAR:
1487 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
1488 return true;
1489 break;
1490 case SHORT:
1491 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
1492 return true;
1493 break;
1494 case INT:
1495 return true;
1496 case CLASS:
1497 switch (unboxedType(s).tag) {
1498 case BYTE:
1499 case CHAR:
1500 case SHORT:
1501 return isAssignable(t, unboxedType(s), warn);
1502 }
1503 break;
1504 }
1505 }
1506 return isConvertible(t, s, warn);
1507 }
1508 // </editor-fold>
1510 // <editor-fold defaultstate="collapsed" desc="erasure">
1511 /**
1512 * The erasure of t {@code |t|} -- the type that results when all
1513 * type parameters in t are deleted.
1514 */
1515 public Type erasure(Type t) {
1516 return erasure(t, false);
1517 }
1518 //where
1519 private Type erasure(Type t, boolean recurse) {
1520 if (t.tag <= lastBaseTag)
1521 return t; /* fast special case */
1522 else
1523 return erasure.visit(t, recurse);
1524 }
1525 // where
1526 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
1527 public Type visitType(Type t, Boolean recurse) {
1528 if (t.tag <= lastBaseTag)
1529 return t; /*fast special case*/
1530 else
1531 return t.map(recurse ? erasureRecFun : erasureFun);
1532 }
1534 @Override
1535 public Type visitWildcardType(WildcardType t, Boolean recurse) {
1536 return erasure(upperBound(t), recurse);
1537 }
1539 @Override
1540 public Type visitClassType(ClassType t, Boolean recurse) {
1541 Type erased = t.tsym.erasure(Types.this);
1542 if (recurse) {
1543 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
1544 }
1545 return erased;
1546 }
1548 @Override
1549 public Type visitTypeVar(TypeVar t, Boolean recurse) {
1550 return erasure(t.bound, recurse);
1551 }
1553 @Override
1554 public Type visitErrorType(ErrorType t, Boolean recurse) {
1555 return t;
1556 }
1557 };
1559 private Mapping erasureFun = new Mapping ("erasure") {
1560 public Type apply(Type t) { return erasure(t); }
1561 };
1563 private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
1564 public Type apply(Type t) { return erasureRecursive(t); }
1565 };
1567 public List<Type> erasure(List<Type> ts) {
1568 return Type.map(ts, erasureFun);
1569 }
1571 public Type erasureRecursive(Type t) {
1572 return erasure(t, true);
1573 }
1575 public List<Type> erasureRecursive(List<Type> ts) {
1576 return Type.map(ts, erasureRecFun);
1577 }
1578 // </editor-fold>
1580 // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
1581 /**
1582 * Make a compound type from non-empty list of types
1583 *
1584 * @param bounds the types from which the compound type is formed
1585 * @param supertype is objectType if all bounds are interfaces,
1586 * null otherwise.
1587 */
1588 public Type makeCompoundType(List<Type> bounds,
1589 Type supertype) {
1590 ClassSymbol bc =
1591 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
1592 Type.moreInfo
1593 ? names.fromString(bounds.toString())
1594 : names.empty,
1595 syms.noSymbol);
1596 if (bounds.head.tag == TYPEVAR)
1597 // error condition, recover
1598 bc.erasure_field = syms.objectType;
1599 else
1600 bc.erasure_field = erasure(bounds.head);
1601 bc.members_field = new Scope(bc);
1602 ClassType bt = (ClassType)bc.type;
1603 bt.allparams_field = List.nil();
1604 if (supertype != null) {
1605 bt.supertype_field = supertype;
1606 bt.interfaces_field = bounds;
1607 } else {
1608 bt.supertype_field = bounds.head;
1609 bt.interfaces_field = bounds.tail;
1610 }
1611 assert bt.supertype_field.tsym.completer != null
1612 || !bt.supertype_field.isInterface()
1613 : bt.supertype_field;
1614 return bt;
1615 }
1617 /**
1618 * Same as {@link #makeCompoundType(List,Type)}, except that the
1619 * second parameter is computed directly. Note that this might
1620 * cause a symbol completion. Hence, this version of
1621 * makeCompoundType may not be called during a classfile read.
1622 */
1623 public Type makeCompoundType(List<Type> bounds) {
1624 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1625 supertype(bounds.head) : null;
1626 return makeCompoundType(bounds, supertype);
1627 }
1629 /**
1630 * A convenience wrapper for {@link #makeCompoundType(List)}; the
1631 * arguments are converted to a list and passed to the other
1632 * method. Note that this might cause a symbol completion.
1633 * Hence, this version of makeCompoundType may not be called
1634 * during a classfile read.
1635 */
1636 public Type makeCompoundType(Type bound1, Type bound2) {
1637 return makeCompoundType(List.of(bound1, bound2));
1638 }
1639 // </editor-fold>
1641 // <editor-fold defaultstate="collapsed" desc="supertype">
1642 public Type supertype(Type t) {
1643 return supertype.visit(t);
1644 }
1645 // where
1646 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
1648 public Type visitType(Type t, Void ignored) {
1649 // A note on wildcards: there is no good way to
1650 // determine a supertype for a super bounded wildcard.
1651 return null;
1652 }
1654 @Override
1655 public Type visitClassType(ClassType t, Void ignored) {
1656 if (t.supertype_field == null) {
1657 Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
1658 // An interface has no superclass; its supertype is Object.
1659 if (t.isInterface())
1660 supertype = ((ClassType)t.tsym.type).supertype_field;
1661 if (t.supertype_field == null) {
1662 List<Type> actuals = classBound(t).allparams();
1663 List<Type> formals = t.tsym.type.allparams();
1664 if (t.hasErasedSupertypes()) {
1665 t.supertype_field = erasureRecursive(supertype);
1666 } else if (formals.nonEmpty()) {
1667 t.supertype_field = subst(supertype, formals, actuals);
1668 }
1669 else {
1670 t.supertype_field = supertype;
1671 }
1672 }
1673 }
1674 return t.supertype_field;
1675 }
1677 /**
1678 * The supertype is always a class type. If the type
1679 * variable's bounds start with a class type, this is also
1680 * the supertype. Otherwise, the supertype is
1681 * java.lang.Object.
1682 */
1683 @Override
1684 public Type visitTypeVar(TypeVar t, Void ignored) {
1685 if (t.bound.tag == TYPEVAR ||
1686 (!t.bound.isCompound() && !t.bound.isInterface())) {
1687 return t.bound;
1688 } else {
1689 return supertype(t.bound);
1690 }
1691 }
1693 @Override
1694 public Type visitArrayType(ArrayType t, Void ignored) {
1695 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
1696 return arraySuperType();
1697 else
1698 return new ArrayType(supertype(t.elemtype), t.tsym);
1699 }
1701 @Override
1702 public Type visitErrorType(ErrorType t, Void ignored) {
1703 return t;
1704 }
1705 };
1706 // </editor-fold>
1708 // <editor-fold defaultstate="collapsed" desc="interfaces">
1709 /**
1710 * Return the interfaces implemented by this class.
1711 */
1712 public List<Type> interfaces(Type t) {
1713 return interfaces.visit(t);
1714 }
1715 // where
1716 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
1718 public List<Type> visitType(Type t, Void ignored) {
1719 return List.nil();
1720 }
1722 @Override
1723 public List<Type> visitClassType(ClassType t, Void ignored) {
1724 if (t.interfaces_field == null) {
1725 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
1726 if (t.interfaces_field == null) {
1727 // If t.interfaces_field is null, then t must
1728 // be a parameterized type (not to be confused
1729 // with a generic type declaration).
1730 // Terminology:
1731 // Parameterized type: List<String>
1732 // Generic type declaration: class List<E> { ... }
1733 // So t corresponds to List<String> and
1734 // t.tsym.type corresponds to List<E>.
1735 // The reason t must be parameterized type is
1736 // that completion will happen as a side
1737 // effect of calling
1738 // ClassSymbol.getInterfaces. Since
1739 // t.interfaces_field is null after
1740 // completion, we can assume that t is not the
1741 // type of a class/interface declaration.
1742 assert t != t.tsym.type : t.toString();
1743 List<Type> actuals = t.allparams();
1744 List<Type> formals = t.tsym.type.allparams();
1745 if (t.hasErasedSupertypes()) {
1746 t.interfaces_field = erasureRecursive(interfaces);
1747 } else if (formals.nonEmpty()) {
1748 t.interfaces_field =
1749 upperBounds(subst(interfaces, formals, actuals));
1750 }
1751 else {
1752 t.interfaces_field = interfaces;
1753 }
1754 }
1755 }
1756 return t.interfaces_field;
1757 }
1759 @Override
1760 public List<Type> visitTypeVar(TypeVar t, Void ignored) {
1761 if (t.bound.isCompound())
1762 return interfaces(t.bound);
1764 if (t.bound.isInterface())
1765 return List.of(t.bound);
1767 return List.nil();
1768 }
1769 };
1770 // </editor-fold>
1772 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
1773 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>();
1775 public boolean isDerivedRaw(Type t) {
1776 Boolean result = isDerivedRawCache.get(t);
1777 if (result == null) {
1778 result = isDerivedRawInternal(t);
1779 isDerivedRawCache.put(t, result);
1780 }
1781 return result;
1782 }
1784 public boolean isDerivedRawInternal(Type t) {
1785 if (t.isErroneous())
1786 return false;
1787 return
1788 t.isRaw() ||
1789 supertype(t) != null && isDerivedRaw(supertype(t)) ||
1790 isDerivedRaw(interfaces(t));
1791 }
1793 public boolean isDerivedRaw(List<Type> ts) {
1794 List<Type> l = ts;
1795 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
1796 return l.nonEmpty();
1797 }
1798 // </editor-fold>
1800 // <editor-fold defaultstate="collapsed" desc="setBounds">
1801 /**
1802 * Set the bounds field of the given type variable to reflect a
1803 * (possibly multiple) list of bounds.
1804 * @param t a type variable
1805 * @param bounds the bounds, must be nonempty
1806 * @param supertype is objectType if all bounds are interfaces,
1807 * null otherwise.
1808 */
1809 public void setBounds(TypeVar t, List<Type> bounds, Type supertype) {
1810 if (bounds.tail.isEmpty())
1811 t.bound = bounds.head;
1812 else
1813 t.bound = makeCompoundType(bounds, supertype);
1814 t.rank_field = -1;
1815 }
1817 /**
1818 * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
1819 * third parameter is computed directly. Note that this test
1820 * might cause a symbol completion. Hence, this version of
1821 * setBounds may not be called during a classfile read.
1822 */
1823 public void setBounds(TypeVar t, List<Type> bounds) {
1824 Type supertype = (bounds.head.tsym.flags() & INTERFACE) != 0 ?
1825 supertype(bounds.head) : null;
1826 setBounds(t, bounds, supertype);
1827 t.rank_field = -1;
1828 }
1829 // </editor-fold>
1831 // <editor-fold defaultstate="collapsed" desc="getBounds">
1832 /**
1833 * Return list of bounds of the given type variable.
1834 */
1835 public List<Type> getBounds(TypeVar t) {
1836 if (t.bound.isErroneous() || !t.bound.isCompound())
1837 return List.of(t.bound);
1838 else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
1839 return interfaces(t).prepend(supertype(t));
1840 else
1841 // No superclass was given in bounds.
1842 // In this case, supertype is Object, erasure is first interface.
1843 return interfaces(t);
1844 }
1845 // </editor-fold>
1847 // <editor-fold defaultstate="collapsed" desc="classBound">
1848 /**
1849 * If the given type is a (possibly selected) type variable,
1850 * return the bounding class of this type, otherwise return the
1851 * type itself.
1852 */
1853 public Type classBound(Type t) {
1854 return classBound.visit(t);
1855 }
1856 // where
1857 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
1859 public Type visitType(Type t, Void ignored) {
1860 return t;
1861 }
1863 @Override
1864 public Type visitClassType(ClassType t, Void ignored) {
1865 Type outer1 = classBound(t.getEnclosingType());
1866 if (outer1 != t.getEnclosingType())
1867 return new ClassType(outer1, t.getTypeArguments(), t.tsym);
1868 else
1869 return t;
1870 }
1872 @Override
1873 public Type visitTypeVar(TypeVar t, Void ignored) {
1874 return classBound(supertype(t));
1875 }
1877 @Override
1878 public Type visitErrorType(ErrorType t, Void ignored) {
1879 return t;
1880 }
1881 };
1882 // </editor-fold>
1884 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
1885 /**
1886 * Returns true iff the first signature is a <em>sub
1887 * signature</em> of the other. This is <b>not</b> an equivalence
1888 * relation.
1889 *
1890 * @see "The Java Language Specification, Third Ed. (8.4.2)."
1891 * @see #overrideEquivalent(Type t, Type s)
1892 * @param t first signature (possibly raw).
1893 * @param s second signature (could be subjected to erasure).
1894 * @return true if t is a sub signature of s.
1895 */
1896 public boolean isSubSignature(Type t, Type s) {
1897 return hasSameArgs(t, s) || hasSameArgs(t, erasure(s));
1898 }
1900 /**
1901 * Returns true iff these signatures are related by <em>override
1902 * equivalence</em>. This is the natural extension of
1903 * isSubSignature to an equivalence relation.
1904 *
1905 * @see "The Java Language Specification, Third Ed. (8.4.2)."
1906 * @see #isSubSignature(Type t, Type s)
1907 * @param t a signature (possible raw, could be subjected to
1908 * erasure).
1909 * @param s a signature (possible raw, could be subjected to
1910 * erasure).
1911 * @return true if either argument is a sub signature of the other.
1912 */
1913 public boolean overrideEquivalent(Type t, Type s) {
1914 return hasSameArgs(t, s) ||
1915 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
1916 }
1918 /**
1919 * Does t have the same arguments as s? It is assumed that both
1920 * types are (possibly polymorphic) method types. Monomorphic
1921 * method types "have the same arguments", if their argument lists
1922 * are equal. Polymorphic method types "have the same arguments",
1923 * if they have the same arguments after renaming all type
1924 * variables of one to corresponding type variables in the other,
1925 * where correspondence is by position in the type parameter list.
1926 */
1927 public boolean hasSameArgs(Type t, Type s) {
1928 return hasSameArgs.visit(t, s);
1929 }
1930 // where
1931 private TypeRelation hasSameArgs = new TypeRelation() {
1933 public Boolean visitType(Type t, Type s) {
1934 throw new AssertionError();
1935 }
1937 @Override
1938 public Boolean visitMethodType(MethodType t, Type s) {
1939 return s.tag == METHOD
1940 && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
1941 }
1943 @Override
1944 public Boolean visitForAll(ForAll t, Type s) {
1945 if (s.tag != FORALL)
1946 return false;
1948 ForAll forAll = (ForAll)s;
1949 return hasSameBounds(t, forAll)
1950 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
1951 }
1953 @Override
1954 public Boolean visitErrorType(ErrorType t, Type s) {
1955 return false;
1956 }
1957 };
1958 // </editor-fold>
1960 // <editor-fold defaultstate="collapsed" desc="subst">
1961 public List<Type> subst(List<Type> ts,
1962 List<Type> from,
1963 List<Type> to) {
1964 return new Subst(from, to).subst(ts);
1965 }
1967 /**
1968 * Substitute all occurrences of a type in `from' with the
1969 * corresponding type in `to' in 't'. Match lists `from' and `to'
1970 * from the right: If lists have different length, discard leading
1971 * elements of the longer list.
1972 */
1973 public Type subst(Type t, List<Type> from, List<Type> to) {
1974 return new Subst(from, to).subst(t);
1975 }
1977 private class Subst extends UnaryVisitor<Type> {
1978 List<Type> from;
1979 List<Type> to;
1981 public Subst(List<Type> from, List<Type> to) {
1982 int fromLength = from.length();
1983 int toLength = to.length();
1984 while (fromLength > toLength) {
1985 fromLength--;
1986 from = from.tail;
1987 }
1988 while (fromLength < toLength) {
1989 toLength--;
1990 to = to.tail;
1991 }
1992 this.from = from;
1993 this.to = to;
1994 }
1996 Type subst(Type t) {
1997 if (from.tail == null)
1998 return t;
1999 else
2000 return visit(t);
2001 }
2003 List<Type> subst(List<Type> ts) {
2004 if (from.tail == null)
2005 return ts;
2006 boolean wild = false;
2007 if (ts.nonEmpty() && from.nonEmpty()) {
2008 Type head1 = subst(ts.head);
2009 List<Type> tail1 = subst(ts.tail);
2010 if (head1 != ts.head || tail1 != ts.tail)
2011 return tail1.prepend(head1);
2012 }
2013 return ts;
2014 }
2016 public Type visitType(Type t, Void ignored) {
2017 return t;
2018 }
2020 @Override
2021 public Type visitMethodType(MethodType t, Void ignored) {
2022 List<Type> argtypes = subst(t.argtypes);
2023 Type restype = subst(t.restype);
2024 List<Type> thrown = subst(t.thrown);
2025 if (argtypes == t.argtypes &&
2026 restype == t.restype &&
2027 thrown == t.thrown)
2028 return t;
2029 else
2030 return new MethodType(argtypes, restype, thrown, t.tsym);
2031 }
2033 @Override
2034 public Type visitTypeVar(TypeVar t, Void ignored) {
2035 for (List<Type> from = this.from, to = this.to;
2036 from.nonEmpty();
2037 from = from.tail, to = to.tail) {
2038 if (t == from.head) {
2039 return to.head.withTypeVar(t);
2040 }
2041 }
2042 return t;
2043 }
2045 @Override
2046 public Type visitClassType(ClassType t, Void ignored) {
2047 if (!t.isCompound()) {
2048 List<Type> typarams = t.getTypeArguments();
2049 List<Type> typarams1 = subst(typarams);
2050 Type outer = t.getEnclosingType();
2051 Type outer1 = subst(outer);
2052 if (typarams1 == typarams && outer1 == outer)
2053 return t;
2054 else
2055 return new ClassType(outer1, typarams1, t.tsym);
2056 } else {
2057 Type st = subst(supertype(t));
2058 List<Type> is = upperBounds(subst(interfaces(t)));
2059 if (st == supertype(t) && is == interfaces(t))
2060 return t;
2061 else
2062 return makeCompoundType(is.prepend(st));
2063 }
2064 }
2066 @Override
2067 public Type visitWildcardType(WildcardType t, Void ignored) {
2068 Type bound = t.type;
2069 if (t.kind != BoundKind.UNBOUND)
2070 bound = subst(bound);
2071 if (bound == t.type) {
2072 return t;
2073 } else {
2074 if (t.isExtendsBound() && bound.isExtendsBound())
2075 bound = upperBound(bound);
2076 return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
2077 }
2078 }
2080 @Override
2081 public Type visitArrayType(ArrayType t, Void ignored) {
2082 Type elemtype = subst(t.elemtype);
2083 if (elemtype == t.elemtype)
2084 return t;
2085 else
2086 return new ArrayType(upperBound(elemtype), t.tsym);
2087 }
2089 @Override
2090 public Type visitForAll(ForAll t, Void ignored) {
2091 List<Type> tvars1 = substBounds(t.tvars, from, to);
2092 Type qtype1 = subst(t.qtype);
2093 if (tvars1 == t.tvars && qtype1 == t.qtype) {
2094 return t;
2095 } else if (tvars1 == t.tvars) {
2096 return new ForAll(tvars1, qtype1);
2097 } else {
2098 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
2099 }
2100 }
2102 @Override
2103 public Type visitErrorType(ErrorType t, Void ignored) {
2104 return t;
2105 }
2106 }
2108 public List<Type> substBounds(List<Type> tvars,
2109 List<Type> from,
2110 List<Type> to) {
2111 if (tvars.isEmpty())
2112 return tvars;
2113 if (tvars.tail.isEmpty())
2114 // fast common case
2115 return List.<Type>of(substBound((TypeVar)tvars.head, from, to));
2116 ListBuffer<Type> newBoundsBuf = lb();
2117 boolean changed = false;
2118 // calculate new bounds
2119 for (Type t : tvars) {
2120 TypeVar tv = (TypeVar) t;
2121 Type bound = subst(tv.bound, from, to);
2122 if (bound != tv.bound)
2123 changed = true;
2124 newBoundsBuf.append(bound);
2125 }
2126 if (!changed)
2127 return tvars;
2128 ListBuffer<Type> newTvars = lb();
2129 // create new type variables without bounds
2130 for (Type t : tvars) {
2131 newTvars.append(new TypeVar(t.tsym, null, syms.botType));
2132 }
2133 // the new bounds should use the new type variables in place
2134 // of the old
2135 List<Type> newBounds = newBoundsBuf.toList();
2136 from = tvars;
2137 to = newTvars.toList();
2138 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
2139 newBounds.head = subst(newBounds.head, from, to);
2140 }
2141 newBounds = newBoundsBuf.toList();
2142 // set the bounds of new type variables to the new bounds
2143 for (Type t : newTvars.toList()) {
2144 TypeVar tv = (TypeVar) t;
2145 tv.bound = newBounds.head;
2146 newBounds = newBounds.tail;
2147 }
2148 return newTvars.toList();
2149 }
2151 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
2152 Type bound1 = subst(t.bound, from, to);
2153 if (bound1 == t.bound)
2154 return t;
2155 else
2156 return new TypeVar(t.tsym, bound1, syms.botType);
2157 }
2158 // </editor-fold>
2160 // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
2161 /**
2162 * Does t have the same bounds for quantified variables as s?
2163 */
2164 boolean hasSameBounds(ForAll t, ForAll s) {
2165 List<Type> l1 = t.tvars;
2166 List<Type> l2 = s.tvars;
2167 while (l1.nonEmpty() && l2.nonEmpty() &&
2168 isSameType(l1.head.getUpperBound(),
2169 subst(l2.head.getUpperBound(),
2170 s.tvars,
2171 t.tvars))) {
2172 l1 = l1.tail;
2173 l2 = l2.tail;
2174 }
2175 return l1.isEmpty() && l2.isEmpty();
2176 }
2177 // </editor-fold>
2179 // <editor-fold defaultstate="collapsed" desc="newInstances">
2180 /** Create new vector of type variables from list of variables
2181 * changing all recursive bounds from old to new list.
2182 */
2183 public List<Type> newInstances(List<Type> tvars) {
2184 List<Type> tvars1 = Type.map(tvars, newInstanceFun);
2185 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
2186 TypeVar tv = (TypeVar) l.head;
2187 tv.bound = subst(tv.bound, tvars, tvars1);
2188 }
2189 return tvars1;
2190 }
2191 static private Mapping newInstanceFun = new Mapping("newInstanceFun") {
2192 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
2193 };
2194 // </editor-fold>
2196 // <editor-fold defaultstate="collapsed" desc="createErrorType">
2197 public Type createErrorType(Type originalType) {
2198 return new ErrorType(originalType, syms.errSymbol);
2199 }
2201 public Type createErrorType(ClassSymbol c, Type originalType) {
2202 return new ErrorType(c, originalType);
2203 }
2205 public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
2206 return new ErrorType(name, container, originalType);
2207 }
2208 // </editor-fold>
2210 // <editor-fold defaultstate="collapsed" desc="rank">
2211 /**
2212 * The rank of a class is the length of the longest path between
2213 * the class and java.lang.Object in the class inheritance
2214 * graph. Undefined for all but reference types.
2215 */
2216 public int rank(Type t) {
2217 switch(t.tag) {
2218 case CLASS: {
2219 ClassType cls = (ClassType)t;
2220 if (cls.rank_field < 0) {
2221 Name fullname = cls.tsym.getQualifiedName();
2222 if (fullname == names.java_lang_Object)
2223 cls.rank_field = 0;
2224 else {
2225 int r = rank(supertype(cls));
2226 for (List<Type> l = interfaces(cls);
2227 l.nonEmpty();
2228 l = l.tail) {
2229 if (rank(l.head) > r)
2230 r = rank(l.head);
2231 }
2232 cls.rank_field = r + 1;
2233 }
2234 }
2235 return cls.rank_field;
2236 }
2237 case TYPEVAR: {
2238 TypeVar tvar = (TypeVar)t;
2239 if (tvar.rank_field < 0) {
2240 int r = rank(supertype(tvar));
2241 for (List<Type> l = interfaces(tvar);
2242 l.nonEmpty();
2243 l = l.tail) {
2244 if (rank(l.head) > r) r = rank(l.head);
2245 }
2246 tvar.rank_field = r + 1;
2247 }
2248 return tvar.rank_field;
2249 }
2250 case ERROR:
2251 return 0;
2252 default:
2253 throw new AssertionError();
2254 }
2255 }
2256 // </editor-fold>
2258 // <editor-fold defaultstate="collapsed" desc="printType">
2259 /**
2260 * Visitor for generating a string representation of a given type
2261 * accordingly to a given locale
2262 */
2263 public String toString(Type t, Locale locale) {
2264 return typePrinter.visit(t, locale);
2265 }
2266 // where
2267 private TypePrinter typePrinter = new TypePrinter();
2269 public class TypePrinter extends DefaultTypeVisitor<String, Locale> {
2271 public String visit(List<Type> ts, Locale locale) {
2272 ListBuffer<String> sbuf = lb();
2273 for (Type t : ts) {
2274 sbuf.append(visit(t, locale));
2275 }
2276 return sbuf.toList().toString();
2277 }
2279 @Override
2280 public String visitCapturedType(CapturedType t, Locale locale) {
2281 return messages.getLocalizedString("compiler.misc.type.captureof",
2282 (t.hashCode() & 0xFFFFFFFFL) % Type.CapturedType.PRIME,
2283 visit(t.wildcard, locale));
2284 }
2286 @Override
2287 public String visitForAll(ForAll t, Locale locale) {
2288 return "<" + visit(t.tvars, locale) + ">" + visit(t.qtype, locale);
2289 }
2291 @Override
2292 public String visitUndetVar(UndetVar t, Locale locale) {
2293 if (t.inst != null) {
2294 return visit(t.inst, locale);
2295 } else {
2296 return visit(t.qtype, locale) + "?";
2297 }
2298 }
2300 @Override
2301 public String visitArrayType(ArrayType t, Locale locale) {
2302 return visit(t.elemtype, locale) + "[]";
2303 }
2305 @Override
2306 public String visitClassType(ClassType t, Locale locale) {
2307 StringBuffer buf = new StringBuffer();
2308 if (t.getEnclosingType().tag == CLASS && t.tsym.owner.kind == Kinds.TYP) {
2309 buf.append(visit(t.getEnclosingType(), locale));
2310 buf.append(".");
2311 buf.append(className(t, false, locale));
2312 } else {
2313 buf.append(className(t, true, locale));
2314 }
2315 if (t.getTypeArguments().nonEmpty()) {
2316 buf.append('<');
2317 buf.append(visit(t.getTypeArguments(), locale));
2318 buf.append(">");
2319 }
2320 return buf.toString();
2321 }
2323 @Override
2324 public String visitMethodType(MethodType t, Locale locale) {
2325 return "(" + printMethodArgs(t.argtypes, false, locale) + ")" + visit(t.restype, locale);
2326 }
2328 @Override
2329 public String visitPackageType(PackageType t, Locale locale) {
2330 return t.tsym.getQualifiedName().toString();
2331 }
2333 @Override
2334 public String visitWildcardType(WildcardType t, Locale locale) {
2335 StringBuffer s = new StringBuffer();
2336 s.append(t.kind);
2337 if (t.kind != UNBOUND) {
2338 s.append(visit(t.type, locale));
2339 }
2340 return s.toString();
2341 }
2344 public String visitType(Type t, Locale locale) {
2345 String s = (t.tsym == null || t.tsym.name == null)
2346 ? messages.getLocalizedString("compiler.misc.type.none")
2347 : t.tsym.name.toString();
2348 return s;
2349 }
2351 protected String className(ClassType t, boolean longform, Locale locale) {
2352 Symbol sym = t.tsym;
2353 if (sym.name.length() == 0 && (sym.flags() & COMPOUND) != 0) {
2354 StringBuffer s = new StringBuffer(visit(supertype(t), locale));
2355 for (List<Type> is = interfaces(t); is.nonEmpty(); is = is.tail) {
2356 s.append("&");
2357 s.append(visit(is.head, locale));
2358 }
2359 return s.toString();
2360 } else if (sym.name.length() == 0) {
2361 String s;
2362 ClassType norm = (ClassType) t.tsym.type;
2363 if (norm == null) {
2364 s = getLocalizedString(locale, "compiler.misc.anonymous.class", (Object) null);
2365 } else if (interfaces(norm).nonEmpty()) {
2366 s = getLocalizedString(locale, "compiler.misc.anonymous.class",
2367 visit(interfaces(norm).head, locale));
2368 } else {
2369 s = getLocalizedString(locale, "compiler.misc.anonymous.class",
2370 visit(supertype(norm), locale));
2371 }
2372 return s;
2373 } else if (longform) {
2374 return sym.getQualifiedName().toString();
2375 } else {
2376 return sym.name.toString();
2377 }
2378 }
2380 protected String printMethodArgs(List<Type> args, boolean varArgs, Locale locale) {
2381 if (!varArgs) {
2382 return visit(args, locale);
2383 } else {
2384 StringBuffer buf = new StringBuffer();
2385 while (args.tail.nonEmpty()) {
2386 buf.append(visit(args.head, locale));
2387 args = args.tail;
2388 buf.append(',');
2389 }
2390 if (args.head.tag == ARRAY) {
2391 buf.append(visit(((ArrayType) args.head).elemtype, locale));
2392 buf.append("...");
2393 } else {
2394 buf.append(visit(args.head, locale));
2395 }
2396 return buf.toString();
2397 }
2398 }
2400 protected String getLocalizedString(Locale locale, String key, Object... args) {
2401 return messages.getLocalizedString(key, args);
2402 }
2403 };
2404 // </editor-fold>
2406 // <editor-fold defaultstate="collapsed" desc="printSymbol">
2407 /**
2408 * Visitor for generating a string representation of a given symbol
2409 * accordingly to a given locale
2410 */
2411 public String toString(Symbol t, Locale locale) {
2412 return symbolPrinter.visit(t, locale);
2413 }
2414 // where
2415 private SymbolPrinter symbolPrinter = new SymbolPrinter();
2417 public class SymbolPrinter extends DefaultSymbolVisitor<String, Locale> {
2419 @Override
2420 public String visitClassSymbol(ClassSymbol sym, Locale locale) {
2421 return sym.name.isEmpty()
2422 ? getLocalizedString(locale, "compiler.misc.anonymous.class", sym.flatname)
2423 : sym.fullname.toString();
2424 }
2426 @Override
2427 public String visitMethodSymbol(MethodSymbol s, Locale locale) {
2428 if ((s.flags() & BLOCK) != 0) {
2429 return s.owner.name.toString();
2430 } else {
2431 String ms = (s.name == names.init)
2432 ? s.owner.name.toString()
2433 : s.name.toString();
2434 if (s.type != null) {
2435 if (s.type.tag == FORALL) {
2436 ms = "<" + typePrinter.visit(s.type.getTypeArguments(), locale) + ">" + ms;
2437 }
2438 ms += "(" + typePrinter.printMethodArgs(
2439 s.type.getParameterTypes(),
2440 (s.flags() & VARARGS) != 0,
2441 locale) + ")";
2442 }
2443 return ms;
2444 }
2445 }
2447 @Override
2448 public String visitOperatorSymbol(OperatorSymbol s, Locale locale) {
2449 return visitMethodSymbol(s, locale);
2450 }
2452 @Override
2453 public String visitPackageSymbol(PackageSymbol s, Locale locale) {
2454 return s.name.isEmpty()
2455 ? getLocalizedString(locale, "compiler.misc.unnamed.package")
2456 : s.fullname.toString();
2457 }
2459 @Override
2460 public String visitSymbol(Symbol s, Locale locale) {
2461 return s.name.toString();
2462 }
2464 public String visit(List<Symbol> ts, Locale locale) {
2465 ListBuffer<String> sbuf = lb();
2466 for (Symbol t : ts) {
2467 sbuf.append(visit(t, locale));
2468 }
2469 return sbuf.toList().toString();
2470 }
2472 protected String getLocalizedString(Locale locale, String key, Object... args) {
2473 return messages.getLocalizedString(key, args);
2474 }
2475 };
2476 // </editor-fold>
2478 // <editor-fold defaultstate="collapsed" desc="toString">
2479 /**
2480 * This toString is slightly more descriptive than the one on Type.
2481 *
2482 * @deprecated Types.toString(Type t, Locale l) provides better support
2483 * for localization
2484 */
2485 @Deprecated
2486 public String toString(Type t) {
2487 if (t.tag == FORALL) {
2488 ForAll forAll = (ForAll)t;
2489 return typaramsString(forAll.tvars) + forAll.qtype;
2490 }
2491 return "" + t;
2492 }
2493 // where
2494 private String typaramsString(List<Type> tvars) {
2495 StringBuffer s = new StringBuffer();
2496 s.append('<');
2497 boolean first = true;
2498 for (Type t : tvars) {
2499 if (!first) s.append(", ");
2500 first = false;
2501 appendTyparamString(((TypeVar)t), s);
2502 }
2503 s.append('>');
2504 return s.toString();
2505 }
2506 private void appendTyparamString(TypeVar t, StringBuffer buf) {
2507 buf.append(t);
2508 if (t.bound == null ||
2509 t.bound.tsym.getQualifiedName() == names.java_lang_Object)
2510 return;
2511 buf.append(" extends "); // Java syntax; no need for i18n
2512 Type bound = t.bound;
2513 if (!bound.isCompound()) {
2514 buf.append(bound);
2515 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
2516 buf.append(supertype(t));
2517 for (Type intf : interfaces(t)) {
2518 buf.append('&');
2519 buf.append(intf);
2520 }
2521 } else {
2522 // No superclass was given in bounds.
2523 // In this case, supertype is Object, erasure is first interface.
2524 boolean first = true;
2525 for (Type intf : interfaces(t)) {
2526 if (!first) buf.append('&');
2527 first = false;
2528 buf.append(intf);
2529 }
2530 }
2531 }
2532 // </editor-fold>
2534 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
2535 /**
2536 * A cache for closures.
2537 *
2538 * <p>A closure is a list of all the supertypes and interfaces of
2539 * a class or interface type, ordered by ClassSymbol.precedes
2540 * (that is, subclasses come first, arbitrary but fixed
2541 * otherwise).
2542 */
2543 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>();
2545 /**
2546 * Returns the closure of a class or interface type.
2547 */
2548 public List<Type> closure(Type t) {
2549 List<Type> cl = closureCache.get(t);
2550 if (cl == null) {
2551 Type st = supertype(t);
2552 if (!t.isCompound()) {
2553 if (st.tag == CLASS) {
2554 cl = insert(closure(st), t);
2555 } else if (st.tag == TYPEVAR) {
2556 cl = closure(st).prepend(t);
2557 } else {
2558 cl = List.of(t);
2559 }
2560 } else {
2561 cl = closure(supertype(t));
2562 }
2563 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
2564 cl = union(cl, closure(l.head));
2565 closureCache.put(t, cl);
2566 }
2567 return cl;
2568 }
2570 /**
2571 * Insert a type in a closure
2572 */
2573 public List<Type> insert(List<Type> cl, Type t) {
2574 if (cl.isEmpty() || t.tsym.precedes(cl.head.tsym, this)) {
2575 return cl.prepend(t);
2576 } else if (cl.head.tsym.precedes(t.tsym, this)) {
2577 return insert(cl.tail, t).prepend(cl.head);
2578 } else {
2579 return cl;
2580 }
2581 }
2583 /**
2584 * Form the union of two closures
2585 */
2586 public List<Type> union(List<Type> cl1, List<Type> cl2) {
2587 if (cl1.isEmpty()) {
2588 return cl2;
2589 } else if (cl2.isEmpty()) {
2590 return cl1;
2591 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
2592 return union(cl1.tail, cl2).prepend(cl1.head);
2593 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
2594 return union(cl1, cl2.tail).prepend(cl2.head);
2595 } else {
2596 return union(cl1.tail, cl2.tail).prepend(cl1.head);
2597 }
2598 }
2600 /**
2601 * Intersect two closures
2602 */
2603 public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
2604 if (cl1 == cl2)
2605 return cl1;
2606 if (cl1.isEmpty() || cl2.isEmpty())
2607 return List.nil();
2608 if (cl1.head.tsym.precedes(cl2.head.tsym, this))
2609 return intersect(cl1.tail, cl2);
2610 if (cl2.head.tsym.precedes(cl1.head.tsym, this))
2611 return intersect(cl1, cl2.tail);
2612 if (isSameType(cl1.head, cl2.head))
2613 return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
2614 if (cl1.head.tsym == cl2.head.tsym &&
2615 cl1.head.tag == CLASS && cl2.head.tag == CLASS) {
2616 if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
2617 Type merge = merge(cl1.head,cl2.head);
2618 return intersect(cl1.tail, cl2.tail).prepend(merge);
2619 }
2620 if (cl1.head.isRaw() || cl2.head.isRaw())
2621 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
2622 }
2623 return intersect(cl1.tail, cl2.tail);
2624 }
2625 // where
2626 class TypePair {
2627 final Type t1;
2628 final Type t2;
2629 TypePair(Type t1, Type t2) {
2630 this.t1 = t1;
2631 this.t2 = t2;
2632 }
2633 @Override
2634 public int hashCode() {
2635 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
2636 }
2637 @Override
2638 public boolean equals(Object obj) {
2639 if (!(obj instanceof TypePair))
2640 return false;
2641 TypePair typePair = (TypePair)obj;
2642 return isSameType(t1, typePair.t1)
2643 && isSameType(t2, typePair.t2);
2644 }
2645 }
2646 Set<TypePair> mergeCache = new HashSet<TypePair>();
2647 private Type merge(Type c1, Type c2) {
2648 ClassType class1 = (ClassType) c1;
2649 List<Type> act1 = class1.getTypeArguments();
2650 ClassType class2 = (ClassType) c2;
2651 List<Type> act2 = class2.getTypeArguments();
2652 ListBuffer<Type> merged = new ListBuffer<Type>();
2653 List<Type> typarams = class1.tsym.type.getTypeArguments();
2655 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
2656 if (containsType(act1.head, act2.head)) {
2657 merged.append(act1.head);
2658 } else if (containsType(act2.head, act1.head)) {
2659 merged.append(act2.head);
2660 } else {
2661 TypePair pair = new TypePair(c1, c2);
2662 Type m;
2663 if (mergeCache.add(pair)) {
2664 m = new WildcardType(lub(upperBound(act1.head),
2665 upperBound(act2.head)),
2666 BoundKind.EXTENDS,
2667 syms.boundClass);
2668 mergeCache.remove(pair);
2669 } else {
2670 m = new WildcardType(syms.objectType,
2671 BoundKind.UNBOUND,
2672 syms.boundClass);
2673 }
2674 merged.append(m.withTypeVar(typarams.head));
2675 }
2676 act1 = act1.tail;
2677 act2 = act2.tail;
2678 typarams = typarams.tail;
2679 }
2680 assert(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
2681 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym);
2682 }
2684 /**
2685 * Return the minimum type of a closure, a compound type if no
2686 * unique minimum exists.
2687 */
2688 private Type compoundMin(List<Type> cl) {
2689 if (cl.isEmpty()) return syms.objectType;
2690 List<Type> compound = closureMin(cl);
2691 if (compound.isEmpty())
2692 return null;
2693 else if (compound.tail.isEmpty())
2694 return compound.head;
2695 else
2696 return makeCompoundType(compound);
2697 }
2699 /**
2700 * Return the minimum types of a closure, suitable for computing
2701 * compoundMin or glb.
2702 */
2703 private List<Type> closureMin(List<Type> cl) {
2704 ListBuffer<Type> classes = lb();
2705 ListBuffer<Type> interfaces = lb();
2706 while (!cl.isEmpty()) {
2707 Type current = cl.head;
2708 if (current.isInterface())
2709 interfaces.append(current);
2710 else
2711 classes.append(current);
2712 ListBuffer<Type> candidates = lb();
2713 for (Type t : cl.tail) {
2714 if (!isSubtypeNoCapture(current, t))
2715 candidates.append(t);
2716 }
2717 cl = candidates.toList();
2718 }
2719 return classes.appendList(interfaces).toList();
2720 }
2722 /**
2723 * Return the least upper bound of pair of types. if the lub does
2724 * not exist return null.
2725 */
2726 public Type lub(Type t1, Type t2) {
2727 return lub(List.of(t1, t2));
2728 }
2730 /**
2731 * Return the least upper bound (lub) of set of types. If the lub
2732 * does not exist return the type of null (bottom).
2733 */
2734 public Type lub(List<Type> ts) {
2735 final int ARRAY_BOUND = 1;
2736 final int CLASS_BOUND = 2;
2737 int boundkind = 0;
2738 for (Type t : ts) {
2739 switch (t.tag) {
2740 case CLASS:
2741 boundkind |= CLASS_BOUND;
2742 break;
2743 case ARRAY:
2744 boundkind |= ARRAY_BOUND;
2745 break;
2746 case TYPEVAR:
2747 do {
2748 t = t.getUpperBound();
2749 } while (t.tag == TYPEVAR);
2750 if (t.tag == ARRAY) {
2751 boundkind |= ARRAY_BOUND;
2752 } else {
2753 boundkind |= CLASS_BOUND;
2754 }
2755 break;
2756 default:
2757 if (t.isPrimitive())
2758 return syms.errType;
2759 }
2760 }
2761 switch (boundkind) {
2762 case 0:
2763 return syms.botType;
2765 case ARRAY_BOUND:
2766 // calculate lub(A[], B[])
2767 List<Type> elements = Type.map(ts, elemTypeFun);
2768 for (Type t : elements) {
2769 if (t.isPrimitive()) {
2770 // if a primitive type is found, then return
2771 // arraySuperType unless all the types are the
2772 // same
2773 Type first = ts.head;
2774 for (Type s : ts.tail) {
2775 if (!isSameType(first, s)) {
2776 // lub(int[], B[]) is Cloneable & Serializable
2777 return arraySuperType();
2778 }
2779 }
2780 // all the array types are the same, return one
2781 // lub(int[], int[]) is int[]
2782 return first;
2783 }
2784 }
2785 // lub(A[], B[]) is lub(A, B)[]
2786 return new ArrayType(lub(elements), syms.arrayClass);
2788 case CLASS_BOUND:
2789 // calculate lub(A, B)
2790 while (ts.head.tag != CLASS && ts.head.tag != TYPEVAR)
2791 ts = ts.tail;
2792 assert !ts.isEmpty();
2793 List<Type> cl = closure(ts.head);
2794 for (Type t : ts.tail) {
2795 if (t.tag == CLASS || t.tag == TYPEVAR)
2796 cl = intersect(cl, closure(t));
2797 }
2798 return compoundMin(cl);
2800 default:
2801 // calculate lub(A, B[])
2802 List<Type> classes = List.of(arraySuperType());
2803 for (Type t : ts) {
2804 if (t.tag != ARRAY) // Filter out any arrays
2805 classes = classes.prepend(t);
2806 }
2807 // lub(A, B[]) is lub(A, arraySuperType)
2808 return lub(classes);
2809 }
2810 }
2811 // where
2812 private Type arraySuperType = null;
2813 private Type arraySuperType() {
2814 // initialized lazily to avoid problems during compiler startup
2815 if (arraySuperType == null) {
2816 synchronized (this) {
2817 if (arraySuperType == null) {
2818 // JLS 10.8: all arrays implement Cloneable and Serializable.
2819 arraySuperType = makeCompoundType(List.of(syms.serializableType,
2820 syms.cloneableType),
2821 syms.objectType);
2822 }
2823 }
2824 }
2825 return arraySuperType;
2826 }
2827 // </editor-fold>
2829 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
2830 public Type glb(Type t, Type s) {
2831 if (s == null)
2832 return t;
2833 else if (isSubtypeNoCapture(t, s))
2834 return t;
2835 else if (isSubtypeNoCapture(s, t))
2836 return s;
2838 List<Type> closure = union(closure(t), closure(s));
2839 List<Type> bounds = closureMin(closure);
2841 if (bounds.isEmpty()) { // length == 0
2842 return syms.objectType;
2843 } else if (bounds.tail.isEmpty()) { // length == 1
2844 return bounds.head;
2845 } else { // length > 1
2846 int classCount = 0;
2847 for (Type bound : bounds)
2848 if (!bound.isInterface())
2849 classCount++;
2850 if (classCount > 1)
2851 return createErrorType(t);
2852 }
2853 return makeCompoundType(bounds);
2854 }
2855 // </editor-fold>
2857 // <editor-fold defaultstate="collapsed" desc="hashCode">
2858 /**
2859 * Compute a hash code on a type.
2860 */
2861 public static int hashCode(Type t) {
2862 return hashCode.visit(t);
2863 }
2864 // where
2865 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() {
2867 public Integer visitType(Type t, Void ignored) {
2868 return t.tag;
2869 }
2871 @Override
2872 public Integer visitClassType(ClassType t, Void ignored) {
2873 int result = visit(t.getEnclosingType());
2874 result *= 127;
2875 result += t.tsym.flatName().hashCode();
2876 for (Type s : t.getTypeArguments()) {
2877 result *= 127;
2878 result += visit(s);
2879 }
2880 return result;
2881 }
2883 @Override
2884 public Integer visitWildcardType(WildcardType t, Void ignored) {
2885 int result = t.kind.hashCode();
2886 if (t.type != null) {
2887 result *= 127;
2888 result += visit(t.type);
2889 }
2890 return result;
2891 }
2893 @Override
2894 public Integer visitArrayType(ArrayType t, Void ignored) {
2895 return visit(t.elemtype) + 12;
2896 }
2898 @Override
2899 public Integer visitTypeVar(TypeVar t, Void ignored) {
2900 return System.identityHashCode(t.tsym);
2901 }
2903 @Override
2904 public Integer visitUndetVar(UndetVar t, Void ignored) {
2905 return System.identityHashCode(t);
2906 }
2908 @Override
2909 public Integer visitErrorType(ErrorType t, Void ignored) {
2910 return 0;
2911 }
2912 };
2913 // </editor-fold>
2915 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
2916 /**
2917 * Does t have a result that is a subtype of the result type of s,
2918 * suitable for covariant returns? It is assumed that both types
2919 * are (possibly polymorphic) method types. Monomorphic method
2920 * types are handled in the obvious way. Polymorphic method types
2921 * require renaming all type variables of one to corresponding
2922 * type variables in the other, where correspondence is by
2923 * position in the type parameter list. */
2924 public boolean resultSubtype(Type t, Type s, Warner warner) {
2925 List<Type> tvars = t.getTypeArguments();
2926 List<Type> svars = s.getTypeArguments();
2927 Type tres = t.getReturnType();
2928 Type sres = subst(s.getReturnType(), svars, tvars);
2929 return covariantReturnType(tres, sres, warner);
2930 }
2932 /**
2933 * Return-Type-Substitutable.
2934 * @see <a href="http://java.sun.com/docs/books/jls/">The Java
2935 * Language Specification, Third Ed. (8.4.5)</a>
2936 */
2937 public boolean returnTypeSubstitutable(Type r1, Type r2) {
2938 if (hasSameArgs(r1, r2))
2939 return resultSubtype(r1, r2, Warner.noWarnings);
2940 else
2941 return covariantReturnType(r1.getReturnType(),
2942 erasure(r2.getReturnType()),
2943 Warner.noWarnings);
2944 }
2946 public boolean returnTypeSubstitutable(Type r1,
2947 Type r2, Type r2res,
2948 Warner warner) {
2949 if (isSameType(r1.getReturnType(), r2res))
2950 return true;
2951 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
2952 return false;
2954 if (hasSameArgs(r1, r2))
2955 return covariantReturnType(r1.getReturnType(), r2res, warner);
2956 if (!source.allowCovariantReturns())
2957 return false;
2958 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
2959 return true;
2960 if (!isSubtype(r1.getReturnType(), erasure(r2res)))
2961 return false;
2962 warner.warnUnchecked();
2963 return true;
2964 }
2966 /**
2967 * Is t an appropriate return type in an overrider for a
2968 * method that returns s?
2969 */
2970 public boolean covariantReturnType(Type t, Type s, Warner warner) {
2971 return
2972 isSameType(t, s) ||
2973 source.allowCovariantReturns() &&
2974 !t.isPrimitive() &&
2975 !s.isPrimitive() &&
2976 isAssignable(t, s, warner);
2977 }
2978 // </editor-fold>
2980 // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
2981 /**
2982 * Return the class that boxes the given primitive.
2983 */
2984 public ClassSymbol boxedClass(Type t) {
2985 return reader.enterClass(syms.boxedName[t.tag]);
2986 }
2988 /**
2989 * Return the primitive type corresponding to a boxed type.
2990 */
2991 public Type unboxedType(Type t) {
2992 if (allowBoxing) {
2993 for (int i=0; i<syms.boxedName.length; i++) {
2994 Name box = syms.boxedName[i];
2995 if (box != null &&
2996 asSuper(t, reader.enterClass(box)) != null)
2997 return syms.typeOfTag[i];
2998 }
2999 }
3000 return Type.noType;
3001 }
3002 // </editor-fold>
3004 // <editor-fold defaultstate="collapsed" desc="Capture conversion">
3005 /*
3006 * JLS 3rd Ed. 5.1.10 Capture Conversion:
3007 *
3008 * Let G name a generic type declaration with n formal type
3009 * parameters A1 ... An with corresponding bounds U1 ... Un. There
3010 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
3011 * where, for 1 <= i <= n:
3012 *
3013 * + If Ti is a wildcard type argument (4.5.1) of the form ? then
3014 * Si is a fresh type variable whose upper bound is
3015 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
3016 * type.
3017 *
3018 * + If Ti is a wildcard type argument of the form ? extends Bi,
3019 * then Si is a fresh type variable whose upper bound is
3020 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
3021 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
3022 * a compile-time error if for any two classes (not interfaces)
3023 * Vi and Vj,Vi is not a subclass of Vj or vice versa.
3024 *
3025 * + If Ti is a wildcard type argument of the form ? super Bi,
3026 * then Si is a fresh type variable whose upper bound is
3027 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
3028 *
3029 * + Otherwise, Si = Ti.
3030 *
3031 * Capture conversion on any type other than a parameterized type
3032 * (4.5) acts as an identity conversion (5.1.1). Capture
3033 * conversions never require a special action at run time and
3034 * therefore never throw an exception at run time.
3035 *
3036 * Capture conversion is not applied recursively.
3037 */
3038 /**
3039 * Capture conversion as specified by JLS 3rd Ed.
3040 */
3041 public Type capture(Type t) {
3042 if (t.tag != CLASS)
3043 return t;
3044 ClassType cls = (ClassType)t;
3045 if (cls.isRaw() || !cls.isParameterized())
3046 return cls;
3048 ClassType G = (ClassType)cls.asElement().asType();
3049 List<Type> A = G.getTypeArguments();
3050 List<Type> T = cls.getTypeArguments();
3051 List<Type> S = freshTypeVariables(T);
3053 List<Type> currentA = A;
3054 List<Type> currentT = T;
3055 List<Type> currentS = S;
3056 boolean captured = false;
3057 while (!currentA.isEmpty() &&
3058 !currentT.isEmpty() &&
3059 !currentS.isEmpty()) {
3060 if (currentS.head != currentT.head) {
3061 captured = true;
3062 WildcardType Ti = (WildcardType)currentT.head;
3063 Type Ui = currentA.head.getUpperBound();
3064 CapturedType Si = (CapturedType)currentS.head;
3065 if (Ui == null)
3066 Ui = syms.objectType;
3067 switch (Ti.kind) {
3068 case UNBOUND:
3069 Si.bound = subst(Ui, A, S);
3070 Si.lower = syms.botType;
3071 break;
3072 case EXTENDS:
3073 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
3074 Si.lower = syms.botType;
3075 break;
3076 case SUPER:
3077 Si.bound = subst(Ui, A, S);
3078 Si.lower = Ti.getSuperBound();
3079 break;
3080 }
3081 if (Si.bound == Si.lower)
3082 currentS.head = Si.bound;
3083 }
3084 currentA = currentA.tail;
3085 currentT = currentT.tail;
3086 currentS = currentS.tail;
3087 }
3088 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
3089 return erasure(t); // some "rare" type involved
3091 if (captured)
3092 return new ClassType(cls.getEnclosingType(), S, cls.tsym);
3093 else
3094 return t;
3095 }
3096 // where
3097 private List<Type> freshTypeVariables(List<Type> types) {
3098 ListBuffer<Type> result = lb();
3099 for (Type t : types) {
3100 if (t.tag == WILDCARD) {
3101 Type bound = ((WildcardType)t).getExtendsBound();
3102 if (bound == null)
3103 bound = syms.objectType;
3104 result.append(new CapturedType(capturedName,
3105 syms.noSymbol,
3106 bound,
3107 syms.botType,
3108 (WildcardType)t));
3109 } else {
3110 result.append(t);
3111 }
3112 }
3113 return result.toList();
3114 }
3115 // </editor-fold>
3117 // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
3118 private List<Type> upperBounds(List<Type> ss) {
3119 if (ss.isEmpty()) return ss;
3120 Type head = upperBound(ss.head);
3121 List<Type> tail = upperBounds(ss.tail);
3122 if (head != ss.head || tail != ss.tail)
3123 return tail.prepend(head);
3124 else
3125 return ss;
3126 }
3128 private boolean sideCast(Type from, Type to, Warner warn) {
3129 // We are casting from type $from$ to type $to$, which are
3130 // non-final unrelated types. This method
3131 // tries to reject a cast by transferring type parameters
3132 // from $to$ to $from$ by common superinterfaces.
3133 boolean reverse = false;
3134 Type target = to;
3135 if ((to.tsym.flags() & INTERFACE) == 0) {
3136 assert (from.tsym.flags() & INTERFACE) != 0;
3137 reverse = true;
3138 to = from;
3139 from = target;
3140 }
3141 List<Type> commonSupers = superClosure(to, erasure(from));
3142 boolean giveWarning = commonSupers.isEmpty();
3143 // The arguments to the supers could be unified here to
3144 // get a more accurate analysis
3145 while (commonSupers.nonEmpty()) {
3146 Type t1 = asSuper(from, commonSupers.head.tsym);
3147 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
3148 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3149 return false;
3150 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
3151 commonSupers = commonSupers.tail;
3152 }
3153 if (giveWarning && !isReifiable(to))
3154 warn.warnUnchecked();
3155 if (!source.allowCovariantReturns())
3156 // reject if there is a common method signature with
3157 // incompatible return types.
3158 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3159 return true;
3160 }
3162 private boolean sideCastFinal(Type from, Type to, Warner warn) {
3163 // We are casting from type $from$ to type $to$, which are
3164 // unrelated types one of which is final and the other of
3165 // which is an interface. This method
3166 // tries to reject a cast by transferring type parameters
3167 // from the final class to the interface.
3168 boolean reverse = false;
3169 Type target = to;
3170 if ((to.tsym.flags() & INTERFACE) == 0) {
3171 assert (from.tsym.flags() & INTERFACE) != 0;
3172 reverse = true;
3173 to = from;
3174 from = target;
3175 }
3176 assert (from.tsym.flags() & FINAL) != 0;
3177 Type t1 = asSuper(from, to.tsym);
3178 if (t1 == null) return false;
3179 Type t2 = to;
3180 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
3181 return false;
3182 if (!source.allowCovariantReturns())
3183 // reject if there is a common method signature with
3184 // incompatible return types.
3185 chk.checkCompatibleAbstracts(warn.pos(), from, to);
3186 if (!isReifiable(target) &&
3187 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
3188 warn.warnUnchecked();
3189 return true;
3190 }
3192 private boolean giveWarning(Type from, Type to) {
3193 // To and from are (possibly different) parameterizations
3194 // of the same class or interface
3195 return to.isParameterized() && !containsType(to.getTypeArguments(), from.getTypeArguments());
3196 }
3198 private List<Type> superClosure(Type t, Type s) {
3199 List<Type> cl = List.nil();
3200 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
3201 if (isSubtype(s, erasure(l.head))) {
3202 cl = insert(cl, l.head);
3203 } else {
3204 cl = union(cl, superClosure(l.head, s));
3205 }
3206 }
3207 return cl;
3208 }
3210 private boolean containsTypeEquivalent(Type t, Type s) {
3211 return
3212 isSameType(t, s) || // shortcut
3213 containsType(t, s) && containsType(s, t);
3214 }
3216 /**
3217 * Adapt a type by computing a substitution which maps a source
3218 * type to a target type.
3219 *
3220 * @param source the source type
3221 * @param target the target type
3222 * @param from the type variables of the computed substitution
3223 * @param to the types of the computed substitution.
3224 */
3225 public void adapt(Type source,
3226 Type target,
3227 ListBuffer<Type> from,
3228 ListBuffer<Type> to) throws AdaptFailure {
3229 Map<Symbol,Type> mapping = new HashMap<Symbol,Type>();
3230 adaptRecursive(source, target, from, to, mapping);
3231 List<Type> fromList = from.toList();
3232 List<Type> toList = to.toList();
3233 while (!fromList.isEmpty()) {
3234 Type val = mapping.get(fromList.head.tsym);
3235 if (toList.head != val)
3236 toList.head = val;
3237 fromList = fromList.tail;
3238 toList = toList.tail;
3239 }
3240 }
3241 // where
3242 private void adaptRecursive(Type source,
3243 Type target,
3244 ListBuffer<Type> from,
3245 ListBuffer<Type> to,
3246 Map<Symbol,Type> mapping) throws AdaptFailure {
3247 if (source.tag == TYPEVAR) {
3248 // Check to see if there is
3249 // already a mapping for $source$, in which case
3250 // the old mapping will be merged with the new
3251 Type val = mapping.get(source.tsym);
3252 if (val != null) {
3253 if (val.isSuperBound() && target.isSuperBound()) {
3254 val = isSubtype(lowerBound(val), lowerBound(target))
3255 ? target : val;
3256 } else if (val.isExtendsBound() && target.isExtendsBound()) {
3257 val = isSubtype(upperBound(val), upperBound(target))
3258 ? val : target;
3259 } else if (!isSameType(val, target)) {
3260 throw new AdaptFailure();
3261 }
3262 } else {
3263 val = target;
3264 from.append(source);
3265 to.append(target);
3266 }
3267 mapping.put(source.tsym, val);
3268 } else if (source.tag == target.tag) {
3269 switch (source.tag) {
3270 case CLASS:
3271 adapt(source.allparams(), target.allparams(),
3272 from, to, mapping);
3273 break;
3274 case ARRAY:
3275 adaptRecursive(elemtype(source), elemtype(target),
3276 from, to, mapping);
3277 break;
3278 case WILDCARD:
3279 if (source.isExtendsBound()) {
3280 adaptRecursive(upperBound(source), upperBound(target),
3281 from, to, mapping);
3282 } else if (source.isSuperBound()) {
3283 adaptRecursive(lowerBound(source), lowerBound(target),
3284 from, to, mapping);
3285 }
3286 break;
3287 }
3288 }
3289 }
3290 public static class AdaptFailure extends Exception {
3291 static final long serialVersionUID = -7490231548272701566L;
3292 }
3294 /**
3295 * Adapt a type by computing a substitution which maps a list of
3296 * source types to a list of target types.
3297 *
3298 * @param source the source type
3299 * @param target the target type
3300 * @param from the type variables of the computed substitution
3301 * @param to the types of the computed substitution.
3302 */
3303 private void adapt(List<Type> source,
3304 List<Type> target,
3305 ListBuffer<Type> from,
3306 ListBuffer<Type> to,
3307 Map<Symbol,Type> mapping) throws AdaptFailure {
3308 if (source.length() == target.length()) {
3309 while (source.nonEmpty()) {
3310 adaptRecursive(source.head, target.head, from, to, mapping);
3311 source = source.tail;
3312 target = target.tail;
3313 }
3314 }
3315 }
3317 private void adaptSelf(Type t,
3318 ListBuffer<Type> from,
3319 ListBuffer<Type> to) {
3320 try {
3321 //if (t.tsym.type != t)
3322 adapt(t.tsym.type, t, from, to);
3323 } catch (AdaptFailure ex) {
3324 // Adapt should never fail calculating a mapping from
3325 // t.tsym.type to t as there can be no merge problem.
3326 throw new AssertionError(ex);
3327 }
3328 }
3330 /**
3331 * Rewrite all type variables (universal quantifiers) in the given
3332 * type to wildcards (existential quantifiers). This is used to
3333 * determine if a cast is allowed. For example, if high is true
3334 * and {@code T <: Number}, then {@code List<T>} is rewritten to
3335 * {@code List<? extends Number>}. Since {@code List<Integer> <:
3336 * List<? extends Number>} a {@code List<T>} can be cast to {@code
3337 * List<Integer>} with a warning.
3338 * @param t a type
3339 * @param high if true return an upper bound; otherwise a lower
3340 * bound
3341 * @param rewriteTypeVars only rewrite captured wildcards if false;
3342 * otherwise rewrite all type variables
3343 * @return the type rewritten with wildcards (existential
3344 * quantifiers) only
3345 */
3346 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
3347 ListBuffer<Type> from = new ListBuffer<Type>();
3348 ListBuffer<Type> to = new ListBuffer<Type>();
3349 adaptSelf(t, from, to);
3350 ListBuffer<Type> rewritten = new ListBuffer<Type>();
3351 List<Type> formals = from.toList();
3352 boolean changed = false;
3353 for (Type arg : to.toList()) {
3354 Type bound;
3355 if (rewriteTypeVars && arg.tag == TYPEVAR) {
3356 TypeVar tv = (TypeVar)arg;
3357 bound = high ? tv.bound : syms.botType;
3358 } else {
3359 bound = high ? upperBound(arg) : lowerBound(arg);
3360 }
3361 Type newarg = bound;
3362 if (arg != bound) {
3363 changed = true;
3364 newarg = high ? makeExtendsWildcard(bound, (TypeVar)formals.head)
3365 : makeSuperWildcard(bound, (TypeVar)formals.head);
3366 }
3367 rewritten.append(newarg);
3368 formals = formals.tail;
3369 }
3370 if (changed)
3371 return subst(t.tsym.type, from.toList(), rewritten.toList());
3372 else
3373 return t;
3374 }
3376 /**
3377 * Create a wildcard with the given upper (extends) bound; create
3378 * an unbounded wildcard if bound is Object.
3379 *
3380 * @param bound the upper bound
3381 * @param formal the formal type parameter that will be
3382 * substituted by the wildcard
3383 */
3384 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
3385 if (bound == syms.objectType) {
3386 return new WildcardType(syms.objectType,
3387 BoundKind.UNBOUND,
3388 syms.boundClass,
3389 formal);
3390 } else {
3391 return new WildcardType(bound,
3392 BoundKind.EXTENDS,
3393 syms.boundClass,
3394 formal);
3395 }
3396 }
3398 /**
3399 * Create a wildcard with the given lower (super) bound; create an
3400 * unbounded wildcard if bound is bottom (type of {@code null}).
3401 *
3402 * @param bound the lower bound
3403 * @param formal the formal type parameter that will be
3404 * substituted by the wildcard
3405 */
3406 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
3407 if (bound.tag == BOT) {
3408 return new WildcardType(syms.objectType,
3409 BoundKind.UNBOUND,
3410 syms.boundClass,
3411 formal);
3412 } else {
3413 return new WildcardType(bound,
3414 BoundKind.SUPER,
3415 syms.boundClass,
3416 formal);
3417 }
3418 }
3420 /**
3421 * A wrapper for a type that allows use in sets.
3422 */
3423 class SingletonType {
3424 final Type t;
3425 SingletonType(Type t) {
3426 this.t = t;
3427 }
3428 public int hashCode() {
3429 return Types.this.hashCode(t);
3430 }
3431 public boolean equals(Object obj) {
3432 return (obj instanceof SingletonType) &&
3433 isSameType(t, ((SingletonType)obj).t);
3434 }
3435 public String toString() {
3436 return t.toString();
3437 }
3438 }
3439 // </editor-fold>
3441 // <editor-fold defaultstate="collapsed" desc="Visitors">
3442 /**
3443 * A default visitor for types. All visitor methods except
3444 * visitType are implemented by delegating to visitType. Concrete
3445 * subclasses must provide an implementation of visitType and can
3446 * override other methods as needed.
3447 *
3448 * @param <R> the return type of the operation implemented by this
3449 * visitor; use Void if no return type is needed.
3450 * @param <S> the type of the second argument (the first being the
3451 * type itself) of the operation implemented by this visitor; use
3452 * Void if a second argument is not needed.
3453 */
3454 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
3455 final public R visit(Type t, S s) { return t.accept(this, s); }
3456 public R visitClassType(ClassType t, S s) { return visitType(t, s); }
3457 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
3458 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
3459 public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
3460 public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
3461 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
3462 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
3463 public R visitForAll(ForAll t, S s) { return visitType(t, s); }
3464 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
3465 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
3466 }
3468 /**
3469 * A default visitor for symbols. All visitor methods except
3470 * visitSymbol are implemented by delegating to visitSymbol. Concrete
3471 * subclasses must provide an implementation of visitSymbol and can
3472 * override other methods as needed.
3473 *
3474 * @param <R> the return type of the operation implemented by this
3475 * visitor; use Void if no return type is needed.
3476 * @param <S> the type of the second argument (the first being the
3477 * symbol itself) of the operation implemented by this visitor; use
3478 * Void if a second argument is not needed.
3479 */
3480 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
3481 final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
3482 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
3483 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
3484 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
3485 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
3486 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
3487 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
3488 }
3490 /**
3491 * A <em>simple</em> visitor for types. This visitor is simple as
3492 * captured wildcards, for-all types (generic methods), and
3493 * undetermined type variables (part of inference) are hidden.
3494 * Captured wildcards are hidden by treating them as type
3495 * variables and the rest are hidden by visiting their qtypes.
3496 *
3497 * @param <R> the return type of the operation implemented by this
3498 * visitor; use Void if no return type is needed.
3499 * @param <S> the type of the second argument (the first being the
3500 * type itself) of the operation implemented by this visitor; use
3501 * Void if a second argument is not needed.
3502 */
3503 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
3504 @Override
3505 public R visitCapturedType(CapturedType t, S s) {
3506 return visitTypeVar(t, s);
3507 }
3508 @Override
3509 public R visitForAll(ForAll t, S s) {
3510 return visit(t.qtype, s);
3511 }
3512 @Override
3513 public R visitUndetVar(UndetVar t, S s) {
3514 return visit(t.qtype, s);
3515 }
3516 }
3518 /**
3519 * A plain relation on types. That is a 2-ary function on the
3520 * form Type × Type → Boolean.
3521 * <!-- In plain text: Type x Type -> Boolean -->
3522 */
3523 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
3525 /**
3526 * A convenience visitor for implementing operations that only
3527 * require one argument (the type itself), that is, unary
3528 * operations.
3529 *
3530 * @param <R> the return type of the operation implemented by this
3531 * visitor; use Void if no return type is needed.
3532 */
3533 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
3534 final public R visit(Type t) { return t.accept(this, null); }
3535 }
3537 /**
3538 * A visitor for implementing a mapping from types to types. The
3539 * default behavior of this class is to implement the identity
3540 * mapping (mapping a type to itself). This can be overridden in
3541 * subclasses.
3542 *
3543 * @param <S> the type of the second argument (the first being the
3544 * type itself) of this mapping; use Void if a second argument is
3545 * not needed.
3546 */
3547 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
3548 final public Type visit(Type t) { return t.accept(this, null); }
3549 public Type visitType(Type t, S s) { return t; }
3550 }
3551 // </editor-fold>
3552 }
