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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.ast;
import static org.codehaus.groovy.ast.ClassHelper.GROOVY_OBJECT_TYPE;
import org.codehaus.groovy.ast.tools.GenericsUtils;
import org.codehaus.groovy.ast.tools.WideningCategories;
import java.lang.reflect.Modifier;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
/**
* This class is used to describe generic type signatures for ClassNodes.
*
* @author Jochen Theodorou
* @see ClassNode
*/
public class GenericsType extends ASTNode {
public static final GenericsType[] EMPTY_ARRAY = new GenericsType[0];
private final ClassNode[] upperBounds;
private final ClassNode lowerBound;
private ClassNode type;
private String name;
private boolean placeholder;
private boolean resolved;
private boolean wildcard;
public GenericsType(ClassNode type, ClassNode[] upperBounds, ClassNode lowerBound) {
this.type = type;
this.name = type.isGenericsPlaceHolder() ? type.getUnresolvedName() : type.getName();
this.upperBounds = upperBounds;
this.lowerBound = lowerBound;
placeholder = type.isGenericsPlaceHolder();
resolved = false;
}
public GenericsType(ClassNode basicType) {
this(basicType, null, null);
}
public ClassNode getType() {
return type;
}
public void setType(ClassNode type) {
this.type = type;
}
public String toString() {
Set visited = new HashSet();
return toString(visited);
}
private String toString(Set visited) {
if (placeholder) visited.add(name);
String ret = wildcard?"?":((type == null || placeholder) ? name : genericsBounds(type, visited));
if (upperBounds != null) {
if (placeholder && upperBounds.length==1 && !upperBounds[0].isGenericsPlaceHolder() && upperBounds[0].getName().equals("java.lang.Object")) {
// T extends Object should just be printed as T
} else {
ret += " extends ";
for (int i = 0; i < upperBounds.length; i++) {
ret += genericsBounds(upperBounds[i], visited);
if (i + 1 < upperBounds.length) ret += " & ";
}
}
} else if (lowerBound != null) {
ret += " super " + genericsBounds(lowerBound, visited);
}
return ret;
}
private String nameOf(ClassNode theType) {
StringBuilder ret = new StringBuilder();
if (theType.isArray()) {
ret.append(nameOf(theType.getComponentType()));
ret.append("[]");
} else {
ret.append(theType.getName());
}
return ret.toString();
}
private String genericsBounds(ClassNode theType, Set visited) {
StringBuilder ret = new StringBuilder();
if (theType.isArray()) {
ret.append(nameOf(theType));
} else if (theType.redirect() instanceof InnerClassNode) {
InnerClassNode innerClassNode = (InnerClassNode) theType.redirect();
String parentClassNodeName = innerClassNode.getOuterClass().getName();
if (Modifier.isStatic(innerClassNode.getModifiers()) || innerClassNode.isInterface()) {
ret.append(innerClassNode.getOuterClass().getName());
} else {
ret.append(genericsBounds(innerClassNode.getOuterClass(), new HashSet()));
}
ret.append(".");
String typeName = theType.getName();
ret.append(typeName.substring(parentClassNodeName.length() + 1));
} else {
ret.append(theType.getName());
}
GenericsType[] genericsTypes = theType.getGenericsTypes();
if (genericsTypes == null || genericsTypes.length == 0)
return ret.toString();
// TODO instead of catching Object here stop it from being placed into type in first place
if (genericsTypes.length == 1 && genericsTypes[0].isPlaceholder() && theType.getName().equals("java.lang.Object")) {
return genericsTypes[0].getName();
}
ret.append("<");
for (int i = 0; i < genericsTypes.length; i++) {
if (i != 0) ret.append(", ");
GenericsType type = genericsTypes[i];
if (type.isPlaceholder() && visited.contains(type.getName())) {
ret.append(type.getName());
}
else {
ret.append(type.toString(visited));
}
}
ret.append(">");
return ret.toString();
}
public ClassNode[] getUpperBounds() {
return upperBounds;
}
public String getName() {
return name;
}
public boolean isPlaceholder() {
return placeholder;
}
public void setPlaceholder(boolean placeholder) {
this.placeholder = placeholder;
type.setGenericsPlaceHolder(placeholder);
}
public boolean isResolved() {
return resolved || placeholder;
}
public void setResolved(boolean res) {
resolved = res;
}
public void setName(String name) {
this.name = name;
}
public boolean isWildcard() {
return wildcard;
}
public void setWildcard(boolean wildcard) {
this.wildcard = wildcard;
}
public ClassNode getLowerBound() {
return lowerBound;
}
/**
* Tells if the provided class node is compatible with this generic type definition
* @param classNode the class node to be checked
* @return true if the class node is compatible with this generics type definition
*/
public boolean isCompatibleWith(ClassNode classNode) {
return new GenericsTypeMatcher().matches(classNode);
}
/**
* Implements generics type comparison.
*/
private class GenericsTypeMatcher {
public boolean implementsInterfaceOrIsSubclassOf(ClassNode type, ClassNode superOrInterface) {
boolean result = type.equals(superOrInterface)
|| type.isDerivedFrom(superOrInterface)
|| type.implementsInterface(superOrInterface);
if (result) {
return true;
}
if (GROOVY_OBJECT_TYPE.equals(superOrInterface) && type.getCompileUnit()!=null) {
// type is being compiled so it will implement GroovyObject later
return true;
}
if (superOrInterface instanceof WideningCategories.LowestUpperBoundClassNode) {
WideningCategories.LowestUpperBoundClassNode cn = (WideningCategories.LowestUpperBoundClassNode) superOrInterface;
result = implementsInterfaceOrIsSubclassOf(type, cn.getSuperClass());
if (result) {
for (ClassNode interfaceNode : cn.getInterfaces()) {
result = implementsInterfaceOrIsSubclassOf(type,interfaceNode);
if (!result) break;
}
}
if (result) return true;
}
if (type.isArray() && superOrInterface.isArray()) {
return implementsInterfaceOrIsSubclassOf(type.getComponentType(), superOrInterface.getComponentType());
}
return false;
}
/**
* Compares this generics type with the one represented by the provided class node. If the provided
* classnode is compatible with the generics specification, returns true. Otherwise, returns false.
* The check is complete, meaning that we also check "nested" generics.
* @param classNode the classnode to be checked
* @return true iff the classnode is compatible with this generics specification
*/
public boolean matches(ClassNode classNode) {
GenericsType[] genericsTypes = classNode.getGenericsTypes();
// diamond always matches
if (genericsTypes!=null && genericsTypes.length==0) return true;
if (classNode.isGenericsPlaceHolder()) {
// if the classnode we compare to is a generics placeholder (like ) then we
// only need to check that the names are equal
if (genericsTypes==null) return true;
if (isWildcard()) {
if (lowerBound!=null) return genericsTypes[0].getName().equals(lowerBound.getUnresolvedName());
if (upperBounds!=null) {
for (ClassNode upperBound : upperBounds) {
String name = upperBound.getGenericsTypes()[0].getName();
if (genericsTypes[0].getName().equals(name)) return true;
}
return false;
}
}
return genericsTypes[0].getName().equals(name);
}
if (wildcard || placeholder) {
// if the current generics spec is a wildcard spec or a placeholder spec
// then we must check upper and lower bounds
if (upperBounds != null) {
// check that the provided classnode is a subclass of all provided upper bounds
boolean upIsOk = true;
for (int i = 0, upperBoundsLength = upperBounds.length; i < upperBoundsLength && upIsOk; i++) {
final ClassNode upperBound = upperBounds[i];
upIsOk = implementsInterfaceOrIsSubclassOf(classNode, upperBound);
}
// if the provided classnode is a subclass of the upper bound
// then check that the generic types supplied by the class node are compatible with
// this generics specification
// for example, we could have the spec saying List but provided classnode
// saying List
upIsOk = upIsOk && checkGenerics(classNode);
return upIsOk;
}
if (lowerBound != null) {
// if a lower bound is declared, then we must perform the same checks that for an upper bound
// but with reversed arguments
return implementsInterfaceOrIsSubclassOf(lowerBound, classNode) && checkGenerics(classNode);
}
// If there are no bounds, the generic type is basically Object, and everything is compatible.
return true;
}
// if this is not a generics placeholder, first compare that types represent the same type
if ((type!=null && !type.equals(classNode))) {
return false;
}
// last, we could have the spec saying List and a classnode saying List so
// we must check that generics are compatible.
// The null check is normally not required but done to prevent from NPEs
return type == null || compareGenericsWithBound(classNode, type);
}
/**
* Iterates over each generics bound of this generics specification, and checks
* that the generics defined by the bound are compatible with the generics specified
* by the type.
* @param classNode the classnode the bounds should be compared with
* @return true if generics from bounds are compatible
*/
private boolean checkGenerics(final ClassNode classNode) {
if (upperBounds!=null) {
for (ClassNode upperBound : upperBounds) {
if (!compareGenericsWithBound(classNode, upperBound)) return false;
}
}
if (lowerBound!=null) {
if (!lowerBound.redirect().isUsingGenerics()) {
if (!compareGenericsWithBound(classNode, lowerBound)) return false;
}
}
return true;
}
/**
* Given a parameterized type (List<String> for example), checks that its
* generic types are compatible with those from a bound.
* @param classNode the classnode from which we will compare generics types
* @param bound the bound to which the types will be compared
* @return true if generics are compatible
*/
private boolean compareGenericsWithBound(final ClassNode classNode, final ClassNode bound) {
if (classNode==null) return false;
if (!bound.isUsingGenerics() || (classNode.getGenericsTypes()==null && classNode.redirect().getGenericsTypes()!=null)) {
// if the bound is not using generics, there's nothing to compare with
return true;
}
if (!classNode.equals(bound)) {
// the class nodes are on different types
// in this situation, we must choose the correct execution path : either the bound
// is an interface and we must find the implementing interface from the classnode
// to compare their parameterized generics, or the bound is a regular class and we
// must compare the bound with a superclass
if (bound.isInterface()) {
Set interfaces = classNode.getAllInterfaces();
// iterate over all interfaces to check if any corresponds to the bound we are
// comparing to
for (ClassNode anInterface : interfaces) {
if (anInterface.equals(bound)) {
// when we obtain an interface, the types represented by the interface
// class node are not parameterized. This means that we must create a
// new class node with the parameterized types that the current class node
// has defined.
ClassNode node = GenericsUtils.parameterizeType(classNode, anInterface);
return compareGenericsWithBound(node, bound);
}
}
}
if (bound instanceof WideningCategories.LowestUpperBoundClassNode) {
// another special case here, where the bound is a "virtual" type
// we must then check the superclass and the interfaces
boolean success = compareGenericsWithBound(classNode, bound.getSuperClass());
if (success) {
ClassNode[] interfaces = bound.getInterfaces();
for (ClassNode anInterface : interfaces) {
success &= compareGenericsWithBound(classNode, anInterface);
if (!success) break;
}
if (success) return true;
}
}
return compareGenericsWithBound(getParameterizedSuperClass(classNode), bound);
}
GenericsType[] cnTypes = classNode.getGenericsTypes();
if (cnTypes==null && classNode.isRedirectNode()) cnTypes=classNode.redirect().getGenericsTypes();
if (cnTypes==null) {
// may happen if generic type is Foo and classnode is Foo -> Foo
return true;
}
GenericsType[] redirectBoundGenericTypes = bound.redirect().getGenericsTypes();
Map classNodePlaceholders = GenericsUtils.extractPlaceholders(classNode);
Map boundPlaceHolders = GenericsUtils.extractPlaceholders(bound);
boolean match = true;
for (int i = 0; redirectBoundGenericTypes!=null && i < redirectBoundGenericTypes.length && match; i++) {
GenericsType redirectBoundType = redirectBoundGenericTypes[i];
GenericsType classNodeType = cnTypes[i];
// The following code has been commented out because it causes GROOVY-5415
// However, commenting doesn't make any test fail, which is curious...
if (classNodeType.isPlaceholder()) {
String name = classNodeType.getName();
if (redirectBoundType.isPlaceholder()) {
match = name.equals(redirectBoundType.getName());
if (!match) {
GenericsType genericsType = boundPlaceHolders.get(redirectBoundType.getName());
match = false;
if (genericsType!=null) {
if (genericsType.isPlaceholder()) {
match = true;
} else if (genericsType.isWildcard()) {
if (genericsType.getUpperBounds()!=null) {
for (ClassNode up : genericsType.getUpperBounds()) {
match |= redirectBoundType.isCompatibleWith(up);
}
if (genericsType.getLowerBound()!=null) {
match |= redirectBoundType.isCompatibleWith(genericsType.getLowerBound());
}
}
}
}
}
} else {
if (classNodePlaceholders.containsKey(name)) classNodeType=classNodePlaceholders.get(name);
match = classNodeType.isCompatibleWith(redirectBoundType.getType());
}
} else {
if (redirectBoundType.isPlaceholder()) {
if (classNodeType.isPlaceholder()) {
match = classNodeType.getName().equals(redirectBoundType.getName());
} else {
String name = redirectBoundType.getName();
if (boundPlaceHolders.containsKey(name)) {
redirectBoundType = boundPlaceHolders.get(name);
boolean wildcard = redirectBoundType.isWildcard();
boolean placeholder = redirectBoundType.isPlaceholder();
if (placeholder || wildcard) {
// placeholder aliases, like Map -> Map
// redirectBoundType = classNodePlaceholders.get(name);
if (wildcard) {
// ex: Comparable <=> Comparable
if (redirectBoundType.lowerBound!=null) {
GenericsType gt = new GenericsType(redirectBoundType.lowerBound);
if (gt.isPlaceholder()) {
// check for recursive generic typedef, like in
// >
if (classNodePlaceholders.containsKey(gt.getName())) {
gt = classNodePlaceholders.get(gt.getName());
}
}
match = implementsInterfaceOrIsSubclassOf(gt.getType(), classNodeType.getType());
}
if (match && redirectBoundType.upperBounds!=null) {
for (ClassNode upperBound : redirectBoundType.upperBounds) {
GenericsType gt = new GenericsType(upperBound);
if (gt.isPlaceholder()) {
// check for recursive generic typedef, like in
// >
if (classNodePlaceholders.containsKey(gt.getName())) {
gt = classNodePlaceholders.get(gt.getName());
}
}
match = match &&
(implementsInterfaceOrIsSubclassOf(classNodeType.getType(), gt.getType())
|| classNodeType.isCompatibleWith(gt.getType())); // workaround for GROOVY-6095
if (!match) break;
}
}
return match;
} else {
redirectBoundType = classNodePlaceholders.get(name);
}
}
}
match = redirectBoundType.isCompatibleWith(classNodeType.getType());
}
} else {
// todo: the check for isWildcard should be replaced with a more complete check
match = redirectBoundType.isWildcard() || classNodeType.isCompatibleWith(redirectBoundType.getType());
}
}
}
if (!match) return false;
return true;
}
}
/**
* If you have a class which extends a class using generics, returns the superclass with parameterized types. For
* example, if you have:
* class MyList<T> extends LinkedList<T>
* def list = new MyList<String>
*
* then the parameterized superclass for MyList<String> is LinkedList<String>
* @param classNode the class for which we want to return the parameterized superclass
* @return the parameterized superclass
*/
private static ClassNode getParameterizedSuperClass(ClassNode classNode) {
if (ClassHelper.OBJECT_TYPE.equals(classNode)) return null;
ClassNode superClass = classNode.getUnresolvedSuperClass();
if (superClass==null) {
return ClassHelper.OBJECT_TYPE;
}
if (!classNode.isUsingGenerics() || !superClass.isUsingGenerics()) return superClass;
GenericsType[] genericsTypes = classNode.getGenericsTypes();
GenericsType[] redirectGenericTypes = classNode.redirect().getGenericsTypes();
superClass = superClass.getPlainNodeReference();
if (genericsTypes==null || redirectGenericTypes==null || superClass.getGenericsTypes()==null) return superClass;
for (int i = 0, genericsTypesLength = genericsTypes.length; i < genericsTypesLength; i++) {
if (redirectGenericTypes[i].isPlaceholder()) {
final GenericsType genericsType = genericsTypes[i];
GenericsType[] superGenericTypes = superClass.getGenericsTypes();
for (int j = 0, superGenericTypesLength = superGenericTypes.length; j < superGenericTypesLength; j++) {
final GenericsType superGenericType = superGenericTypes[j];
if (superGenericType.isPlaceholder() && superGenericType.getName().equals(redirectGenericTypes[i].getName())) {
superGenericTypes[j] = genericsType;
}
}
}
}
return superClass;
}
}