1.1 --- a/src/share/classes/com/sun/tools/javac/comp/Lower.java Fri Feb 18 16:17:44 2011 +0000
1.2 +++ b/src/share/classes/com/sun/tools/javac/comp/Lower.java Fri Feb 18 15:55:20 2011 -0800
1.3 @@ -1425,25 +1425,55 @@
1.4 }
1.5 }
1.6
1.7 - /** Optionally replace a try statement with an automatic resource
1.8 - * management (ARM) block.
1.9 + /**
1.10 + * Optionally replace a try statement with the desugaring of a
1.11 + * try-with-resources statement. The canonical desugaring of
1.12 + *
1.13 + * try ResourceSpecification
1.14 + * Block
1.15 + *
1.16 + * is
1.17 + *
1.18 + * {
1.19 + * final VariableModifiers_minus_final R #resource = Expression;
1.20 + * Throwable #primaryException = null;
1.21 + *
1.22 + * try ResourceSpecificationtail
1.23 + * Block
1.24 + * catch (Throwable #t) {
1.25 + * #primaryException = t;
1.26 + * throw #t;
1.27 + * } finally {
1.28 + * if (#resource != null) {
1.29 + * if (#primaryException != null) {
1.30 + * try {
1.31 + * #resource.close();
1.32 + * } catch(Throwable #suppressedException) {
1.33 + * #primaryException.addSuppressed(#suppressedException);
1.34 + * }
1.35 + * } else {
1.36 + * #resource.close();
1.37 + * }
1.38 + * }
1.39 + * }
1.40 + *
1.41 * @param tree The try statement to inspect.
1.42 - * @return An ARM block, or the original try block if there are no
1.43 - * resources to manage.
1.44 + * @return A a desugared try-with-resources tree, or the original
1.45 + * try block if there are no resources to manage.
1.46 */
1.47 - JCTree makeArmTry(JCTry tree) {
1.48 + JCTree makeTwrTry(JCTry tree) {
1.49 make_at(tree.pos());
1.50 twrVars = twrVars.dup();
1.51 - JCBlock armBlock = makeArmBlock(tree.resources, tree.body, 0);
1.52 + JCBlock twrBlock = makeTwrBlock(tree.resources, tree.body, 0);
1.53 if (tree.catchers.isEmpty() && tree.finalizer == null)
1.54 - result = translate(armBlock);
1.55 + result = translate(twrBlock);
1.56 else
1.57 - result = translate(make.Try(armBlock, tree.catchers, tree.finalizer));
1.58 + result = translate(make.Try(twrBlock, tree.catchers, tree.finalizer));
1.59 twrVars = twrVars.leave();
1.60 return result;
1.61 }
1.62
1.63 - private JCBlock makeArmBlock(List<JCTree> resources, JCBlock block, int depth) {
1.64 + private JCBlock makeTwrBlock(List<JCTree> resources, JCBlock block, int depth) {
1.65 if (resources.isEmpty())
1.66 return block;
1.67
1.68 @@ -1497,16 +1527,16 @@
1.69
1.70 int oldPos = make.pos;
1.71 make.at(TreeInfo.endPos(block));
1.72 - JCBlock finallyClause = makeArmFinallyClause(primaryException, expr);
1.73 + JCBlock finallyClause = makeTwrFinallyClause(primaryException, expr);
1.74 make.at(oldPos);
1.75 - JCTry outerTry = make.Try(makeArmBlock(resources.tail, block, depth + 1),
1.76 + JCTry outerTry = make.Try(makeTwrBlock(resources.tail, block, depth + 1),
1.77 List.<JCCatch>of(catchClause),
1.78 finallyClause);
1.79 stats.add(outerTry);
1.80 return make.Block(0L, stats.toList());
1.81 }
1.82
1.83 - private JCBlock makeArmFinallyClause(Symbol primaryException, JCExpression resource) {
1.84 + private JCBlock makeTwrFinallyClause(Symbol primaryException, JCExpression resource) {
1.85 // primaryException.addSuppressed(catchException);
1.86 VarSymbol catchException =
1.87 new VarSymbol(0, make.paramName(2),
1.88 @@ -1525,22 +1555,30 @@
1.89 List<JCCatch> catchClauses = List.<JCCatch>of(make.Catch(catchExceptionDecl, catchBlock));
1.90 JCTry tryTree = make.Try(tryBlock, catchClauses, null);
1.91
1.92 - // if (resource != null) resourceClose;
1.93 - JCExpression nullCheck = makeBinary(JCTree.NE,
1.94 - make.Ident(primaryException),
1.95 - makeNull());
1.96 - JCIf closeIfStatement = make.If(nullCheck,
1.97 + // if (primaryException != null) {try...} else resourceClose;
1.98 + JCIf closeIfStatement = make.If(makeNonNullCheck(make.Ident(primaryException)),
1.99 tryTree,
1.100 makeResourceCloseInvocation(resource));
1.101 - return make.Block(0L, List.<JCStatement>of(closeIfStatement));
1.102 +
1.103 + // if (#resource != null) { if (primaryException ... }
1.104 + return make.Block(0L,
1.105 + List.<JCStatement>of(make.If(makeNonNullCheck(resource),
1.106 + closeIfStatement,
1.107 + null)));
1.108 }
1.109
1.110 private JCStatement makeResourceCloseInvocation(JCExpression resource) {
1.111 // create resource.close() method invocation
1.112 - JCExpression resourceClose = makeCall(resource, names.close, List.<JCExpression>nil());
1.113 + JCExpression resourceClose = makeCall(resource,
1.114 + names.close,
1.115 + List.<JCExpression>nil());
1.116 return make.Exec(resourceClose);
1.117 }
1.118
1.119 + private JCExpression makeNonNullCheck(JCExpression expression) {
1.120 + return makeBinary(JCTree.NE, expression, makeNull());
1.121 + }
1.122 +
1.123 /** Construct a tree that represents the outer instance
1.124 * <C.this>. Never pick the current `this'.
1.125 * @param pos The source code position to be used for the tree.
1.126 @@ -3573,7 +3611,7 @@
1.127 if (tree.resources.isEmpty()) {
1.128 super.visitTry(tree);
1.129 } else {
1.130 - result = makeArmTry(tree);
1.131 + result = makeTwrTry(tree);
1.132 }
1.133 }
1.134
