8235541: Extend javax.lang.model to cover binding variables

Reviewed-by: darcy

test/langtools/tools/javac/processing/model/element/TestBindingVariable.java

@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) 2010, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug  8235541
+ * @summary Test that the binding variable kind is appropriately set
+ * @library /tools/javac/lib
+ * @modules jdk.compiler
+ * @build   JavacTestingAbstractProcessor
+ * @compile TestBindingVariable.java
+ * @compile --enable-preview -source ${jdk.version} -processor TestBindingVariable -proc:only TestBindingVariableData.java
+ */
+
+import javax.annotation.processing.*;
+import javax.lang.model.element.*;
+import javax.lang.model.util.*;
+import java.util.*;
+import com.sun.source.tree.*;
+import com.sun.source.util.*;
+
+/**
+ * Using the tree API, retrieve element representations of the
+ * binding variables of the type test pattern, and verify their kind
+ * tags are set appropriately.
+ */
+public class TestBindingVariable extends JavacTestingAbstractProcessor implements AutoCloseable {
+    int bindingVariableCount = 0;
+
+    public boolean process(Set<? extends TypeElement> annotations,
+                          RoundEnvironment roundEnv) {
+       if (!roundEnv.processingOver()) {
+           Trees trees = Trees.instance(processingEnv);
+
+           for(Element rootElement : roundEnv.getRootElements()) {
+               TreePath treePath = trees.getPath(rootElement);
+
+               (new BindingVariableScanner(trees)).
+                   scan(treePath.getCompilationUnit(), null);
+           }
+           if (bindingVariableCount != 2)
+               throw new RuntimeException("Bad binding variable count " +
+                                          bindingVariableCount);
+       }
+       return true;
+    }
+
+    @Override
+    public void close() {}
+
+    /**
+     * Verify that a binding variable modeled as an element behaves
+     * as expected under 6 and latest specific visitors.
+     */
+    private static void testBindingVariable(Element element) {
+        ElementVisitor visitor6 = new ElementKindVisitor6<Void, Void>() {};
+
+        try {
+            visitor6.visit(element);
+            throw new RuntimeException("Expected UnknownElementException not thrown.");
+        } catch (UnknownElementException uee) {
+            ; // Expected.
+        }
+
+        ElementKindVisitor visitorLatest =
+            new ElementKindVisitor<Object, Void>() {
+            @Override
+            public Object visitVariableAsBindingVariable(VariableElement e,
+                                                         Void p) {
+                return e; // a non-null value
+            }
+        };
+
+        if (visitorLatest.visit(element) == null) {
+            throw new RuntimeException("Null result of resource variable visitation.");
+        }
+    }
+
+    class BindingVariableScanner extends TreePathScanner<Void, Void> {
+        private Trees trees;
+
+        public BindingVariableScanner(Trees trees) {
+            super();
+            this.trees = trees;
+        }
+        @Override
+        public Void visitBindingPattern(BindingPatternTree node, Void p) {
+            handleCurrentTreeAsBindingVar();
+            return super.visitBindingPattern(node, p);
+        }
+
+        @Override
+        public Void visitIdentifier(IdentifierTree node, Void p) {
+            if (node.getName().contentEquals("bindingVar")) {
+                handleCurrentTreeAsBindingVar();
+            }
+            return super.visitIdentifier(node, p);
+        }
+
+        private void handleCurrentTreeAsBindingVar() {
+           Element element = trees.getElement(getCurrentPath());
+
+           System.out.println("Name: " + element.getSimpleName() +
+                              "\tKind: " + element.getKind());
+           if (element.getKind() != ElementKind.BINDING_VARIABLE) {
+               throw new RuntimeException("Expected a binding variable, but got: " +
+                                          element.getKind());
+           }
+           testBindingVariable(element);
+           bindingVariableCount++;
+        }
+    }
+}