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

Reviewed-by: darcy
  • Loading branch information
Jan Lahoda
Jan Lahoda committed Dec 9, 2019
1 parent 92a9543 commit ad5ea72286aeae6bf08c557716d497f6716aebb6
@@ -137,7 +137,24 @@
*/
@jdk.internal.PreviewFeature(feature=jdk.internal.PreviewFeature.Feature.RECORDS,
essentialAPI=false)
RECORD_COMPONENT;
RECORD_COMPONENT,

/**
* {@preview Associated with pattern matching for {@code
* instanceof}, a preview feature of the Java language.
*
* This enum constant is associated with <i>pattern
* matching for {@code instanceof}</i>, a preview
* feature of the Java language. Preview features
* may be removed in a future release, or upgraded to permanent
* features of the Java language.}
*
* A binding variable in a pattern .
* @since 14
*/
@jdk.internal.PreviewFeature(feature=jdk.internal.PreviewFeature.Feature.PATTERN_MATCHING_IN_INSTANCEOF,
essentialAPI=false)
BINDING_VARIABLE;

/**
* Returns {@code true} if this is a kind of class:
@@ -136,4 +136,20 @@ public R visitRecordComponent(RecordComponentElement e, P p) {
public R visitTypeAsRecord(TypeElement e, P p) {
return defaultAction(e, p);
}

/**
* Visits a {@code BINDING_VARIABLE} variable element.
*
* @implSpec This implementation calls {@code defaultAction}.
*
* @param e {@inheritDoc}
* @param p {@inheritDoc}
* @return the result of {@code defaultAction}
*
* @since 14
*/
@Override
public R visitVariableAsBindingVariable(VariableElement e, P p) {
return defaultAction(e, p);
}
}
@@ -274,6 +274,9 @@ public R visitVariable(VariableElement e, P p) {
case RESOURCE_VARIABLE:
return visitVariableAsResourceVariable(e, p);

case BINDING_VARIABLE:
return visitVariableAsBindingVariable(e, p);

default:
throw new AssertionError("Bad kind " + k + " for VariableElement" + e);
}
@@ -359,6 +362,21 @@ public R visitVariableAsResourceVariable(VariableElement e, P p) {
return visitUnknown(e, p);
}

/**
* Visits a {@code BINDING_VARIABLE} variable element.
*
* @implSpec This implementation calls {@code visitUnknown}.
*
* @param e the element to visit
* @param p a visitor-specified parameter
* @return the result of {@code visitUnknown}
*
* @since 14
*/
public R visitVariableAsBindingVariable(VariableElement e, P p) {
return visitUnknown(e, p);
}

/**
* {@inheritDoc}
*
@@ -290,6 +290,7 @@ public static KindName kindName(Symbol sym) {
case TYPE_PARAMETER:
return KindName.TYPEVAR;

case BINDING_VARIABLE:
case ENUM_CONSTANT:
case PARAMETER:
case LOCAL_VARIABLE:
@@ -1659,6 +1659,10 @@ public ElementKind getKind() {
return ElementKind.FIELD;
} else if (isResourceVariable()) {
return ElementKind.RESOURCE_VARIABLE;
} else if ((flags & MATCH_BINDING) != 0) {
@SuppressWarnings("preview")
ElementKind kind = ElementKind.BINDING_VARIABLE;
return kind;
} else {
return ElementKind.LOCAL_VARIABLE;
}
@@ -955,6 +955,7 @@ public Type visitType(Type t, List<TypeCompound> s) {
appendTypeAnnotationsToOwner(v, v.getRawTypeAttributes());
}
switch (v.getKind()) {
case BINDING_VARIABLE:
case LOCAL_VARIABLE:
return TypeAnnotationPosition
.localVariable(location.toList(), currentLambda,
@@ -36,7 +36,7 @@ private static void test() {
utility/*getElement:METHOD:test.TestGetElementReferenceData.Base.utility()*/();
target(TestGetElementReferenceData :: test/*getElement:METHOD:test.TestGetElementReferenceData.test()*/);
Object/*getElement:CLASS:java.lang.Object*/ o = null;
if (o/*getElement:LOCAL_VARIABLE:o*/ instanceof String/*getElement:CLASS:java.lang.String*/ str/*getElement:LOCAL_VARIABLE:str*/) ;
if (o/*getElement:LOCAL_VARIABLE:o*/ instanceof String/*getElement:CLASS:java.lang.String*/ str/*getElement:BINDING_VARIABLE:str*/) ;
}
private static void target(Runnable r) { r.run(); }
public static class Base {
@@ -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++;
}
}
}
@@ -0,0 +1,30 @@
/*
* Copyright (c) 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.
*/

public class TestBindingVariableData {

private boolean test(Object o) {
return o instanceof String bindingVar && !bindingVar.isEmpty();
}

}

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