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Groovy: A powerful, dynamic language for the JVM
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.codehaus.groovy.transform;
import groovy.transform.Sortable;
import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.AnnotatedNode;
import org.codehaus.groovy.ast.AnnotationNode;
import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.InnerClassNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.ast.Parameter;
import org.codehaus.groovy.ast.PropertyNode;
import org.codehaus.groovy.classgen.VariableScopeVisitor;
import org.codehaus.groovy.runtime.AbstractComparator;
import org.codehaus.groovy.ast.stmt.BlockStatement;
import org.codehaus.groovy.ast.stmt.Statement;
import org.codehaus.groovy.control.CompilePhase;
import org.codehaus.groovy.control.SourceUnit;
import org.codehaus.groovy.runtime.StringGroovyMethods;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import static org.codehaus.groovy.ast.ClassHelper.isPrimitiveType;
import static org.codehaus.groovy.ast.ClassHelper.make;
import static org.codehaus.groovy.ast.tools.GeneralUtils.*;
import static org.codehaus.groovy.ast.tools.GenericsUtils.makeClassSafe;
import static org.codehaus.groovy.ast.tools.GenericsUtils.makeClassSafeWithGenerics;
import static org.codehaus.groovy.ast.tools.GenericsUtils.newClass;
/**
* Injects a set of Comparators and sort methods.
*
* @author Andres Almiray
* @author Paul King
*/
@GroovyASTTransformation(phase = CompilePhase.CANONICALIZATION)
public class SortableASTTransformation extends AbstractASTTransformation {
private static final ClassNode MY_TYPE = make(Sortable.class);
private static final String MY_TYPE_NAME = "@" + MY_TYPE.getNameWithoutPackage();
private static final ClassNode COMPARABLE_TYPE = makeClassSafe(Comparable.class);
private static final ClassNode COMPARATOR_TYPE = makeClassSafe(Comparator.class);
private static final String VALUE = "value";
private static final String OTHER = "other";
private static final String THIS_HASH = "thisHash";
private static final String OTHER_HASH = "otherHash";
private static final String ARG0 = "arg0";
private static final String ARG1 = "arg1";
public void visit(ASTNode[] nodes, SourceUnit source) {
init(nodes, source);
AnnotationNode annotation = (AnnotationNode) nodes[0];
AnnotatedNode parent = (AnnotatedNode) nodes[1];
if (parent instanceof ClassNode) {
createSortable(annotation, (ClassNode) parent);
}
}
private void createSortable(AnnotationNode annotation, ClassNode classNode) {
List includes = getMemberList(annotation, "includes");
List excludes = getMemberList(annotation, "excludes");
if (!checkIncludeExclude(annotation, excludes, includes, MY_TYPE_NAME)) return;
if (classNode.isInterface()) {
addError(MY_TYPE_NAME + " cannot be applied to interface " + classNode.getName(), annotation);
}
List properties = findProperties(annotation, classNode, includes, excludes);
implementComparable(classNode);
classNode.addMethod(new MethodNode(
"compareTo",
ACC_PUBLIC,
ClassHelper.int_TYPE,
params(param(newClass(classNode), OTHER)),
ClassNode.EMPTY_ARRAY,
createCompareToMethodBody(properties)
));
for (PropertyNode property : properties) {
createComparatorFor(classNode, property);
}
new VariableScopeVisitor(sourceUnit, true).visitClass(classNode);
}
private void implementComparable(ClassNode classNode) {
if (!classNode.implementsInterface(COMPARABLE_TYPE)) {
classNode.addInterface(makeClassSafeWithGenerics(Comparable.class, classNode));
}
}
private static Statement createCompareToMethodBody(List properties) {
List statements = new ArrayList();
// if (this.is(other)) return 0;
statements.add(ifS(callThisX("is", args(OTHER)), returnS(constX(0))));
if (properties.isEmpty()) {
// perhaps overkill but let compareTo be based on hashes for commutativity
// return this.hashCode() <=> other.hashCode()
statements.add(declS(varX(THIS_HASH, ClassHelper.Integer_TYPE), callX(varX("this"), "hashCode")));
statements.add(declS(varX(OTHER_HASH, ClassHelper.Integer_TYPE), callX(varX(OTHER), "hashCode")));
statements.add(returnS(cmpX(varX(THIS_HASH), varX(OTHER_HASH))));
} else {
// int value = 0;
statements.add(declS(varX(VALUE, ClassHelper.int_TYPE), constX(0)));
for (PropertyNode property : properties) {
String propName = property.getName();
// value = this.prop <=> other.prop;
statements.add(assignS(varX(VALUE), cmpX(propX(varX("this"), propName), propX(varX(OTHER), propName))));
// if (value != 0) return value;
statements.add(ifS(neX(varX(VALUE), constX(0)), returnS(varX(VALUE))));
}
// objects are equal
statements.add(returnS(constX(0)));
}
final BlockStatement body = new BlockStatement();
body.addStatements(statements);
return body;
}
private static Statement createCompareMethodBody(PropertyNode property) {
String propName = property.getName();
return block(
// if (arg0 == arg1) return 0;
ifS(eqX(varX(ARG0), varX(ARG1)), returnS(constX(0))),
// if (arg0 != null && arg1 == null) return -1;
ifS(andX(notNullX(varX(ARG0)), equalsNullX(varX(ARG1))), returnS(constX(-1))),
// if (arg0 == null && arg1 != null) return 1;
ifS(andX(equalsNullX(varX(ARG0)), notNullX(varX(ARG1))), returnS(constX(1))),
// return arg0.prop <=> arg1.prop;
returnS(cmpX(propX(varX(ARG0), propName), propX(varX(ARG1), propName)))
);
}
private static void createComparatorFor(ClassNode classNode, PropertyNode property) {
String propName = property.getName();
String className = classNode.getName() + "$" + StringGroovyMethods.capitalize(propName) + "Comparator";
ClassNode superClass = makeClassSafeWithGenerics(AbstractComparator.class, classNode);
InnerClassNode cmpClass = new InnerClassNode(classNode, className, ACC_PRIVATE | ACC_STATIC, superClass);
classNode.getModule().addClass(cmpClass);
cmpClass.addMethod(new MethodNode(
"compare",
ACC_PUBLIC,
ClassHelper.int_TYPE,
params(param(newClass(classNode), ARG0), param(newClass(classNode), ARG1)),
ClassNode.EMPTY_ARRAY,
createCompareMethodBody(property)
));
String fieldName = "this$" + StringGroovyMethods.capitalize(propName) + "Comparator";
// private final Comparator this$Comparator = new $Comparator();
FieldNode cmpField = classNode.addField(
fieldName,
ACC_STATIC | ACC_FINAL | ACC_PRIVATE | ACC_SYNTHETIC,
COMPARATOR_TYPE,
ctorX(cmpClass));
classNode.addMethod(new MethodNode(
"comparatorBy" + StringGroovyMethods.capitalize(propName),
ACC_PUBLIC | ACC_STATIC,
COMPARATOR_TYPE,
Parameter.EMPTY_ARRAY,
ClassNode.EMPTY_ARRAY,
returnS(fieldX(cmpField))
));
}
private List findProperties(AnnotationNode annotation, ClassNode classNode, final List includes, final List excludes) {
List properties = new ArrayList();
for (PropertyNode property : classNode.getProperties()) {
String propertyName = property.getName();
if (property.isStatic() ||
excludes.contains(propertyName) ||
!includes.isEmpty() && !includes.contains(propertyName)) continue;
properties.add(property);
}
for (String name : includes) {
checkKnownProperty(annotation, name, properties);
}
for (PropertyNode pNode : properties) {
checkComparable(pNode);
}
if (!includes.isEmpty()) {
Comparator includeComparator = new Comparator() {
public int compare(PropertyNode o1, PropertyNode o2) {
return new Integer(includes.indexOf(o1.getName())).compareTo(includes.indexOf(o2.getName()));
}
};
Collections.sort(properties, includeComparator);
}
return properties;
}
private void checkComparable(PropertyNode pNode) {
if (pNode.getType().implementsInterface(COMPARABLE_TYPE) || isPrimitiveType(pNode.getType()) || hasAnnotation(pNode.getType(), MY_TYPE)) {
return;
}
addError("Error during " + MY_TYPE_NAME + " processing: property '" +
pNode.getName() + "' must be Comparable", pNode);
}
private void checkKnownProperty(AnnotationNode annotation, String name, List properties) {
for (PropertyNode pNode: properties) {
if (name.equals(pNode.getName())) {
return;
}
}
addError("Error during " + MY_TYPE_NAME + " processing: tried to include unknown property '" +
name + "'", annotation);
}
}