1.1 --- a/src/share/classes/com/sun/tools/javac/code/Types.java Thu Oct 04 13:04:53 2012 +0100
1.2 +++ b/src/share/classes/com/sun/tools/javac/code/Types.java Fri Oct 05 14:35:24 2012 +0100
1.3 @@ -79,8 +79,10 @@
1.4 final boolean allowObjectToPrimitiveCast;
1.5 final ClassReader reader;
1.6 final Check chk;
1.7 + JCDiagnostic.Factory diags;
1.8 List<Warner> warnStack = List.nil();
1.9 final Name capturedName;
1.10 + private final FunctionDescriptorLookupError functionDescriptorLookupError;
1.11
1.12 // <editor-fold defaultstate="collapsed" desc="Instantiating">
1.13 public static Types instance(Context context) {
1.14 @@ -102,6 +104,8 @@
1.15 chk = Check.instance(context);
1.16 capturedName = names.fromString("<captured wildcard>");
1.17 messages = JavacMessages.instance(context);
1.18 + diags = JCDiagnostic.Factory.instance(context);
1.19 + functionDescriptorLookupError = new FunctionDescriptorLookupError();
1.20 }
1.21 // </editor-fold>
1.22
1.23 @@ -296,6 +300,294 @@
1.24 }
1.25 // </editor-fold>
1.26
1.27 + // <editor-fold defaultstate="collapsed" desc="findSam">
1.28 +
1.29 + /**
1.30 + * Exception used to report a function descriptor lookup failure. The exception
1.31 + * wraps a diagnostic that can be used to generate more details error
1.32 + * messages.
1.33 + */
1.34 + public static class FunctionDescriptorLookupError extends RuntimeException {
1.35 + private static final long serialVersionUID = 0;
1.36 +
1.37 + JCDiagnostic diagnostic;
1.38 +
1.39 + FunctionDescriptorLookupError() {
1.40 + this.diagnostic = null;
1.41 + }
1.42 +
1.43 + FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
1.44 + this.diagnostic = diag;
1.45 + return this;
1.46 + }
1.47 +
1.48 + public JCDiagnostic getDiagnostic() {
1.49 + return diagnostic;
1.50 + }
1.51 + }
1.52 +
1.53 + /**
1.54 + * A cache that keeps track of function descriptors associated with given
1.55 + * functional interfaces.
1.56 + */
1.57 + class DescriptorCache {
1.58 +
1.59 + private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<TypeSymbol, Entry>();
1.60 +
1.61 + class FunctionDescriptor {
1.62 + Symbol descSym;
1.63 +
1.64 + FunctionDescriptor(Symbol descSym) {
1.65 + this.descSym = descSym;
1.66 + }
1.67 +
1.68 + public Symbol getSymbol() {
1.69 + return descSym;
1.70 + }
1.71 +
1.72 + public Type getType(Type origin) {
1.73 + return memberType(origin, descSym);
1.74 + }
1.75 + }
1.76 +
1.77 + class Entry {
1.78 + final FunctionDescriptor cachedDescRes;
1.79 + final int prevMark;
1.80 +
1.81 + public Entry(FunctionDescriptor cachedDescRes,
1.82 + int prevMark) {
1.83 + this.cachedDescRes = cachedDescRes;
1.84 + this.prevMark = prevMark;
1.85 + }
1.86 +
1.87 + boolean matches(int mark) {
1.88 + return this.prevMark == mark;
1.89 + }
1.90 + }
1.91 +
1.92 + FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
1.93 + Entry e = _map.get(origin);
1.94 + CompoundScope members = membersClosure(origin.type, false);
1.95 + if (e == null ||
1.96 + !e.matches(members.getMark())) {
1.97 + FunctionDescriptor descRes = findDescriptorInternal(origin, members);
1.98 + _map.put(origin, new Entry(descRes, members.getMark()));
1.99 + return descRes;
1.100 + }
1.101 + else {
1.102 + return e.cachedDescRes;
1.103 + }
1.104 + }
1.105 +
1.106 + /**
1.107 + * Scope filter used to skip methods that should be ignored during
1.108 + * function interface conversion (such as methods overridden by
1.109 + * j.l.Object)
1.110 + */
1.111 + class DescriptorFilter implements Filter<Symbol> {
1.112 +
1.113 + TypeSymbol origin;
1.114 +
1.115 + DescriptorFilter(TypeSymbol origin) {
1.116 + this.origin = origin;
1.117 + }
1.118 +
1.119 + @Override
1.120 + public boolean accepts(Symbol sym) {
1.121 + return sym.kind == Kinds.MTH &&
1.122 + (sym.flags() & ABSTRACT) != 0 &&
1.123 + !overridesObjectMethod(origin, sym) &&
1.124 + notOverridden(sym);
1.125 + }
1.126 +
1.127 + private boolean notOverridden(Symbol msym) {
1.128 + Symbol impl = ((MethodSymbol)msym).implementation(origin, Types.this, false);
1.129 + return impl == null || (impl.flags() & ABSTRACT) != 0;
1.130 + }
1.131 + };
1.132 +
1.133 + /**
1.134 + * Compute the function descriptor associated with a given functional interface
1.135 + */
1.136 + public FunctionDescriptor findDescriptorInternal(TypeSymbol origin, CompoundScope membersCache) throws FunctionDescriptorLookupError {
1.137 + if (!origin.isInterface()) {
1.138 + //t must be an interface
1.139 + throw failure("not.a.functional.intf");
1.140 + }
1.141 +
1.142 + final ListBuffer<Symbol> abstracts = ListBuffer.lb();
1.143 + for (Symbol sym : membersCache.getElements(new DescriptorFilter(origin))) {
1.144 + Type mtype = memberType(origin.type, sym);
1.145 + if (abstracts.isEmpty() ||
1.146 + (sym.name == abstracts.first().name &&
1.147 + overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
1.148 + abstracts.append(sym);
1.149 + } else {
1.150 + //the target method(s) should be the only abstract members of t
1.151 + throw failure("not.a.functional.intf.1",
1.152 + diags.fragment("incompatible.abstracts", Kinds.kindName(origin), origin));
1.153 + }
1.154 + }
1.155 + if (abstracts.isEmpty()) {
1.156 + //t must define a suitable non-generic method
1.157 + throw failure("not.a.functional.intf.1",
1.158 + diags.fragment("no.abstracts", Kinds.kindName(origin), origin));
1.159 + } else if (abstracts.size() == 1) {
1.160 + if (abstracts.first().type.tag == FORALL) {
1.161 + throw failure("invalid.generic.desc.in.functional.intf",
1.162 + abstracts.first(),
1.163 + Kinds.kindName(origin),
1.164 + origin);
1.165 + } else {
1.166 + return new FunctionDescriptor(abstracts.first());
1.167 + }
1.168 + } else { // size > 1
1.169 + for (Symbol msym : abstracts) {
1.170 + if (msym.type.tag == FORALL) {
1.171 + throw failure("invalid.generic.desc.in.functional.intf",
1.172 + abstracts.first(),
1.173 + Kinds.kindName(origin),
1.174 + origin);
1.175 + }
1.176 + }
1.177 + FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
1.178 + if (descRes == null) {
1.179 + //we can get here if the functional interface is ill-formed
1.180 + ListBuffer<JCDiagnostic> descriptors = ListBuffer.lb();
1.181 + for (Symbol desc : abstracts) {
1.182 + String key = desc.type.getThrownTypes().nonEmpty() ?
1.183 + "descriptor.throws" : "descriptor";
1.184 + descriptors.append(diags.fragment(key, desc.name,
1.185 + desc.type.getParameterTypes(),
1.186 + desc.type.getReturnType(),
1.187 + desc.type.getThrownTypes()));
1.188 + }
1.189 + JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
1.190 + new JCDiagnostic.MultilineDiagnostic(diags.fragment("incompatible.descs.in.functional.intf",
1.191 + Kinds.kindName(origin), origin), descriptors.toList());
1.192 + throw failure(incompatibleDescriptors);
1.193 + }
1.194 + return descRes;
1.195 + }
1.196 + }
1.197 +
1.198 + /**
1.199 + * Compute a synthetic type for the target descriptor given a list
1.200 + * of override-equivalent methods in the functional interface type.
1.201 + * The resulting method type is a method type that is override-equivalent
1.202 + * and return-type substitutable with each method in the original list.
1.203 + */
1.204 + private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
1.205 + //pick argument types - simply take the signature that is a
1.206 + //subsignature of all other signatures in the list (as per JLS 8.4.2)
1.207 + List<Symbol> mostSpecific = List.nil();
1.208 + outer: for (Symbol msym1 : methodSyms) {
1.209 + Type mt1 = memberType(origin.type, msym1);
1.210 + for (Symbol msym2 : methodSyms) {
1.211 + Type mt2 = memberType(origin.type, msym2);
1.212 + if (!isSubSignature(mt1, mt2)) {
1.213 + continue outer;
1.214 + }
1.215 + }
1.216 + mostSpecific = mostSpecific.prepend(msym1);
1.217 + }
1.218 + if (mostSpecific.isEmpty()) {
1.219 + return null;
1.220 + }
1.221 +
1.222 +
1.223 + //pick return types - this is done in two phases: (i) first, the most
1.224 + //specific return type is chosen using strict subtyping; if this fails,
1.225 + //a second attempt is made using return type substitutability (see JLS 8.4.5)
1.226 + boolean phase2 = false;
1.227 + Symbol bestSoFar = null;
1.228 + while (bestSoFar == null) {
1.229 + outer: for (Symbol msym1 : mostSpecific) {
1.230 + Type mt1 = memberType(origin.type, msym1);
1.231 + for (Symbol msym2 : methodSyms) {
1.232 + Type mt2 = memberType(origin.type, msym2);
1.233 + if (phase2 ?
1.234 + !returnTypeSubstitutable(mt1, mt2) :
1.235 + !isSubtypeInternal(mt1.getReturnType(), mt2.getReturnType())) {
1.236 + continue outer;
1.237 + }
1.238 + }
1.239 + bestSoFar = msym1;
1.240 + }
1.241 + if (phase2) {
1.242 + break;
1.243 + } else {
1.244 + phase2 = true;
1.245 + }
1.246 + }
1.247 + if (bestSoFar == null) return null;
1.248 +
1.249 + //merge thrown types - form the intersection of all the thrown types in
1.250 + //all the signatures in the list
1.251 + List<Type> thrown = null;
1.252 + for (Symbol msym1 : methodSyms) {
1.253 + Type mt1 = memberType(origin.type, msym1);
1.254 + thrown = (thrown == null) ?
1.255 + mt1.getThrownTypes() :
1.256 + chk.intersect(mt1.getThrownTypes(), thrown);
1.257 + }
1.258 +
1.259 + final List<Type> thrown1 = thrown;
1.260 + return new FunctionDescriptor(bestSoFar) {
1.261 + @Override
1.262 + public Type getType(Type origin) {
1.263 + Type mt = memberType(origin, getSymbol());
1.264 + return new MethodType(mt.getParameterTypes(), mt.getReturnType(), thrown1, syms.methodClass);
1.265 + }
1.266 + };
1.267 + }
1.268 +
1.269 + boolean isSubtypeInternal(Type s, Type t) {
1.270 + return (s.isPrimitive() && t.isPrimitive()) ?
1.271 + isSameType(t, s) :
1.272 + isSubtype(s, t);
1.273 + }
1.274 +
1.275 + FunctionDescriptorLookupError failure(String msg, Object... args) {
1.276 + return failure(diags.fragment(msg, args));
1.277 + }
1.278 +
1.279 + FunctionDescriptorLookupError failure(JCDiagnostic diag) {
1.280 + return functionDescriptorLookupError.setMessage(diag);
1.281 + }
1.282 + }
1.283 +
1.284 + private DescriptorCache descCache = new DescriptorCache();
1.285 +
1.286 + /**
1.287 + * Find the method descriptor associated to this class symbol - if the
1.288 + * symbol 'origin' is not a functional interface, an exception is thrown.
1.289 + */
1.290 + public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
1.291 + return descCache.get(origin).getSymbol();
1.292 + }
1.293 +
1.294 + /**
1.295 + * Find the type of the method descriptor associated to this class symbol -
1.296 + * if the symbol 'origin' is not a functional interface, an exception is thrown.
1.297 + */
1.298 + public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
1.299 + return descCache.get(origin.tsym).getType(origin);
1.300 + }
1.301 +
1.302 + /**
1.303 + * Is given type a functional interface?
1.304 + */
1.305 + public boolean isFunctionalInterface(TypeSymbol tsym) {
1.306 + try {
1.307 + findDescriptorSymbol(tsym);
1.308 + return true;
1.309 + } catch (FunctionDescriptorLookupError ex) {
1.310 + return false;
1.311 + }
1.312 + }
1.313 + // </editor-fold>
1.314 +
1.315 // <editor-fold defaultstate="collapsed" desc="isSubtype">
1.316 /**
1.317 * Is t an unchecked subtype of s?
1.318 @@ -1215,7 +1507,10 @@
1.319 * Returns the lower bounds of the formals of a method.
1.320 */
1.321 public List<Type> lowerBoundArgtypes(Type t) {
1.322 - return map(t.getParameterTypes(), lowerBoundMapping);
1.323 + return lowerBounds(t.getParameterTypes());
1.324 + }
1.325 + public List<Type> lowerBounds(List<Type> ts) {
1.326 + return map(ts, lowerBoundMapping);
1.327 }
1.328 private final Mapping lowerBoundMapping = new Mapping("lowerBound") {
1.329 public Type apply(Type t) {
1.330 @@ -2007,6 +2302,15 @@
1.331 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
1.332 }
1.333
1.334 + public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
1.335 + for (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) {
1.336 + if (msym.overrides(e.sym, origin, Types.this, true)) {
1.337 + return true;
1.338 + }
1.339 + }
1.340 + return false;
1.341 + }
1.342 +
1.343 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
1.344 class ImplementationCache {
1.345
