src/share/classes/com/sun/tools/javac/comp/Attr.java

*** 113,122 ****
--- 113,124 ----
          allowVarargs = source.allowVarargs();
          allowEnums = source.allowEnums();
          allowBoxing = source.allowBoxing();
          allowCovariantReturns = source.allowCovariantReturns();
          allowAnonOuterThis = source.allowAnonOuterThis();
+         allowStringsInSwitch = source.allowStringsInSwitch();
+         sourceName = source.name;
          relax = (options.get("-retrofit") != null ||
                   options.get("-relax") != null);
          useBeforeDeclarationWarning = options.get("useBeforeDeclarationWarning") != null;
          allowInvokedynamic = options.get("invokedynamic") != null;
          enableSunApiLintControl = options.get("enableSunApiLintControl") != null;
*** 165,174 ****
--- 167,186 ----
       * Switch: allow lint infrastructure to control Sun proprietary
       * API warnings.
       */
      boolean enableSunApiLintControl;
  
+     /**
+      * Switch: allow strings in switch?
+      */
+     boolean allowStringsInSwitch;
+ 
+     /**
+      * Switch: name of source level; used for error reporting.
+      */
+     String sourceName;
+ 
      /** Check kind and type of given tree against protokind and prototype.
       *  If check succeeds, store type in tree and return it.
       *  If check fails, store errType in tree and return it.
       *  No checks are performed if the prototype is a method type.
       *  It is not necessary in this case since we know that kind and type
*** 884,896 ****
              env.dup(tree, env.info.dup(env.info.scope.dup()));
  
          boolean enumSwitch =
              allowEnums &&
              (seltype.tsym.flags() & Flags.ENUM) != 0;
!         if (!enumSwitch)
              seltype = chk.checkType(tree.selector.pos(), seltype, syms.intType);
  
          // Attribute all cases and
          // check that there are no duplicate case labels or default clauses.
          Set<Object> labels = new HashSet<Object>(); // The set of case labels.
          boolean hasDefault = false;      // Is there a default label?
          for (List<JCCase> l = tree.cases; l.nonEmpty(); l = l.tail) {
--- 896,917 ----
              env.dup(tree, env.info.dup(env.info.scope.dup()));
  
          boolean enumSwitch =
              allowEnums &&
              (seltype.tsym.flags() & Flags.ENUM) != 0;
!         boolean stringSwitch = false;
!         if (types.isSameType(seltype, syms.stringType)) {
!             if (allowStringsInSwitch) {
!                 stringSwitch = true;
!             } else {
!                 log.error(tree.selector.pos(), "string.switch.not.supported.in.source", sourceName);
!             }
!         }
!         if (!enumSwitch && !stringSwitch)
              seltype = chk.checkType(tree.selector.pos(), seltype, syms.intType);
  
+ 
          // Attribute all cases and
          // check that there are no duplicate case labels or default clauses.
          Set<Object> labels = new HashSet<Object>(); // The set of case labels.
          boolean hasDefault = false;      // Is there a default label?
          for (List<JCCase> l = tree.cases; l.nonEmpty(); l = l.tail) {
*** 907,917 ****
                      }
                  } else {
                      Type pattype = attribExpr(c.pat, switchEnv, seltype);
                      if (pattype.tag != ERROR) {
                          if (pattype.constValue() == null) {
!                             log.error(c.pat.pos(), "const.expr.req");
                          } else if (labels.contains(pattype.constValue())) {
                              log.error(c.pos(), "duplicate.case.label");
                          } else {
                              labels.add(pattype.constValue());
                          }
--- 928,939 ----
                      }
                  } else {
                      Type pattype = attribExpr(c.pat, switchEnv, seltype);
                      if (pattype.tag != ERROR) {
                          if (pattype.constValue() == null) {
!                             log.error(c.pat.pos(),
!                                       (stringSwitch ? "string.const.req" : "const.expr.req"));
                          } else if (labels.contains(pattype.constValue())) {
                              log.error(c.pos(), "duplicate.case.label");
                          } else {
                              labels.add(pattype.constValue());
                          }