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Groovy: A powerful, dynamic language for the JVM
/*
* Copyright 2003-2012 the original author or authors.
*
* Licensed 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.ast.tools;
import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.GenericsType;
import java.util.HashMap;
import java.util.Map;
/**
* Utility methods to deal with generic types.
*
* @author Cedric Champeau
*/
public class GenericsUtils {
public static final GenericsType[] EMPTY_GENERICS_ARRAY = new GenericsType[0];
/**
* Given a parameterized type and a generic type information, aligns actual type parameters. For example, if a
* class uses generic type <T,U,V>
(redirectGenericTypes), is used with actual type parameters
* <java.lang.String, U,V>
, then a class or interface using generic types <T,V>
* will be aligned to <java.lang.String,V>
* @param redirectGenericTypes the type arguments or the redirect class node
* @param parameterizedTypes the actual type arguments used on this class node
* @param alignmentTarget the generic type arguments to which we want to align to
* @return aligned type arguments
*/
public static GenericsType[] alignGenericTypes(final GenericsType[] redirectGenericTypes, final GenericsType[] parameterizedTypes, final GenericsType[] alignmentTarget) {
if (alignmentTarget==null) return EMPTY_GENERICS_ARRAY;
if (parameterizedTypes==null || parameterizedTypes.length==0) return alignmentTarget;
GenericsType[] generics = new GenericsType[alignmentTarget.length];
for (int i = 0, scgtLength = alignmentTarget.length; i < scgtLength; i++) {
final GenericsType currentTarget = alignmentTarget[i];
GenericsType match = null;
if (redirectGenericTypes!=null) {
for (int j = 0; j < redirectGenericTypes.length && match == null; j++) {
GenericsType redirectGenericType = redirectGenericTypes[j];
if (redirectGenericType.isCompatibleWith(currentTarget.getType())) {
if (currentTarget.isPlaceholder() && redirectGenericType.isPlaceholder() && !currentTarget.getName().equals(redirectGenericType.getName())) {
// check if there's a potential better match
boolean skip = false;
for (int k=j+1; k extractPlaceholders(ClassNode cn) {
HashMap ret = new HashMap();
extractPlaceholders(cn, ret);
return ret;
}
/**
* For a given classnode, fills in the supplied map with the parameterized
* types it defines.
* @param node
* @param map
*/
public static void extractPlaceholders(ClassNode node, Map map) {
if (node == null) return;
if (!node.isUsingGenerics() || !node.isRedirectNode()) return;
GenericsType[] parameterized = node.getGenericsTypes();
if (parameterized == null || parameterized.length == 0) return;
GenericsType[] redirectGenericsTypes = node.redirect().getGenericsTypes();
if (redirectGenericsTypes==null) redirectGenericsTypes = parameterized;
for (int i = 0; i < redirectGenericsTypes.length; i++) {
GenericsType redirectType = redirectGenericsTypes[i];
if (redirectType.isPlaceholder()) {
String name = redirectType.getName();
if (!map.containsKey(name)) map.put(name, parameterized[i]);
}
}
if (node.isArray()) {
extractPlaceholders(node.getComponentType(), map);
}
}
/**
* Interface class nodes retrieved from {@link org.codehaus.groovy.ast.ClassNode#getInterfaces()}
* or {@link org.codehaus.groovy.ast.ClassNode#getAllInterfaces()} are returned with generic type
* arguments. This method allows returning a parameterized interface given the parameterized class
* node which implements this interface.
* @param hint the class node where generics types are parameterized
* @param target the interface we want to parameterize generics types
* @return a parameterized interface class node
* @deprecated Use #parameterizeType instead
*/
public static ClassNode parameterizeInterfaceGenerics(final ClassNode hint, final ClassNode target) {
return parameterizeType(hint, target);
}
/**
* Interface class nodes retrieved from {@link org.codehaus.groovy.ast.ClassNode#getInterfaces()}
* or {@link org.codehaus.groovy.ast.ClassNode#getAllInterfaces()} are returned with generic type
* arguments. This method allows returning a parameterized interface given the parameterized class
* node which implements this interface.
* @param hint the class node where generics types are parameterized
* @param target the interface we want to parameterize generics types
* @return a parameterized interface class node
*/
public static ClassNode parameterizeType(final ClassNode hint, final ClassNode target) {
ClassNode interfaceFromClassNode = null;
if (hint.equals(target)) interfaceFromClassNode = hint;
if (ClassHelper.OBJECT_TYPE.equals(target) && target.isUsingGenerics() && target.getGenericsTypes()!=null
&& target.getGenericsTypes()[0].isPlaceholder()) {
// Object
return ClassHelper.getWrapper(hint);
}
if (interfaceFromClassNode==null) {
ClassNode[] interfaces = hint.getInterfaces();
for (ClassNode node : interfaces) {
if (node.equals(target)) {
interfaceFromClassNode = node;
break;
} else if (node.implementsInterface(target)) {
// ex: classNode = LinkedList , node=List , anInterface = Iterable
return parameterizeType(parameterizeType(hint, node), target);
}
}
}
if (interfaceFromClassNode==null && hint.getUnresolvedSuperClass()!=null) {
return parameterizeType(hint.getUnresolvedSuperClass(), target);
}
if (interfaceFromClassNode==null) {
// return target;
interfaceFromClassNode = hint;
}
Map parameters = new HashMap();
extractPlaceholders(hint, parameters);
ClassNode node = target.getPlainNodeReference();
GenericsType[] interfaceGTs = interfaceFromClassNode.getGenericsTypes();
if (interfaceGTs==null) return target;
GenericsType[] types = new GenericsType[interfaceGTs.length];
for (int i = 0; i < interfaceGTs.length; i++) {
GenericsType interfaceGT = interfaceGTs[i];
types[i] = interfaceGT;
if (interfaceGT.isPlaceholder()) {
String name = interfaceGT.getName();
if (parameters.containsKey(name)) {
types[i] = parameters.get(name);
}
}
}
node.setGenericsTypes(types);
return node;
}
}