JDK11 indy string concatenation handler

rt/vm/src/main/java/org/apidesign/vm4brwsr/ByteCodeToJavaScript.java

@@ -45,6 +45,7 @@ protected ByteCodeToJavaScript(final Appendable out) {
         this.output = out;
         this.indyHandlers = new IndyHandler[] {
             new MetafactoryHandler(),
+            new StringConcatHandler(),
         };
     }
 

rt/vm/src/main/java/org/apidesign/vm4brwsr/StringConcatHandler.java

@@ -0,0 +1,70 @@
+/**
+ * Back 2 Browser Bytecode Translator
+ * Copyright (C) 2012-2018 Jaroslav Tulach <jaroslav.tulach@apidesign.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. Look for COPYING file in the top folder.
+ * If not, see http://opensource.org/licenses/GPL-2.0.
+ */
+package org.apidesign.vm4brwsr;
+
+import java.io.IOException;
+
+final class StringConcatHandler extends IndyHandler {
+    StringConcatHandler() {
+        super("java/lang/invoke/StringConcatFactory", "makeConcatWithConstants");
+    }
+
+    @Override
+    protected boolean handle(Ctx ctx) throws IOException {
+        final int fixedArgsCount;
+        String recipe = ctx.bm.clazz.StringValue(ctx.bm.args[0]);
+        final String sig = ctx.mt[1];
+        StringBuilder sigB = new StringBuilder();
+        StringBuilder cnt = new StringBuilder();
+        char[] returnType = {'V'};
+        ByteCodeToJavaScript.countArgs(sig, returnType, sigB, cnt);
+        assert returnType[0] == 'L';
+
+        fixedArgsCount = cnt.length();
+        final CharSequence[] vars = new CharSequence[fixedArgsCount];
+        for (int j = fixedArgsCount - 1; j >= 0; --j) {
+            vars[j] = ctx.stackMapper.popValue();
+        }
+
+
+        ctx.stackMapper.flush(ctx.out);
+
+        final Variable stringVar = ctx.stackMapper.pushA();
+        ctx.out.append("var ").append(stringVar).append(" = ");
+
+        StringBuilder sep = new StringBuilder();
+        sep.append("'");
+        int atVar = 0;
+        for (int j = 0; j < recipe.length(); j++) {
+            char ch = recipe.charAt(j);
+            switch (ch) {
+                case '\1':
+                    ctx.out.append(sep).append("' + ");
+                    ctx.out.append(vars[atVar++]);
+                    sep = new StringBuilder(" + '");
+                    break;
+                case '\2':
+                    throw new IllegalStateException("#2 stackvalue not supported yet");
+                default:
+                    sep.append(ch);
+            }
+        }
+        ctx.out.append(sep).append("'");
+        return true;
+    }
+}

rt/vm11/pom.xml

@@ -35,6 +35,7 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <configuration>
                     <target>11</target>
+                    <testTarget>11</testTarget>
                 </configuration>
             </plugin>
             <plugin>

rt/vm11/src/test/java/org/apidesign/bck2brwsr/vm11/NestMatesTest.java

@@ -32,6 +32,11 @@ public String callProtectedMethod() throws Exception {
         return NestMates.protectedMessage();
     }
 
+    @Compare
+    public String concatenateBothMethods() throws Exception {
+        return NestMates.privateMessage() + NestMates.protectedMessage();
+    }
+
     @Factory
     public static Object[] create() {
         return VMTest.create(NestMatesTest.class);