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Groovy: A powerful, dynamic language for the JVM
/*
* Copyright 2003-2008 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 groovy.util;
import groovy.lang.*;
import org.codehaus.groovy.control.MultipleCompilationErrorsException;
import org.codehaus.groovy.runtime.ConversionHandler;
import org.codehaus.groovy.runtime.DefaultGroovyMethods;
import org.codehaus.groovy.runtime.InvokerHelper;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.*;
/**
* Classes to generate 'Proxy' objects which implement interfaces,
* maps of closures and/or extend classes/delegates.
*
* @author Paul King
* @author Guillaume Laforge
*/
public class ProxyGenerator {
public static final ProxyGenerator INSTANCE = new ProxyGenerator();
static {
// wrap the standard MetaClass with the delegate
setMetaClass(GroovySystem.getMetaClassRegistry().getMetaClass(ProxyGenerator.class));
}
private ClassLoader override = null;
private boolean debug = false;
private boolean emptyMethods = false;
private List objectMethods = getInheritedMethods(Object.class, new ArrayList());
private List groovyObjectMethods = getInheritedMethods(GroovyObject.class, new ArrayList());
public boolean getDebug() {
return debug;
}
/**
* Instructs ProxyGenerator to dump generated Groovy
* source code to standard output during construction. This is useful
* for debugging purposes but should be turned off in production.
*
* @param debug true if you want generated source to be printed
*/
public void setDebug(boolean debug) {
this.debug = debug;
}
public boolean getEmptyMethods() {
return emptyMethods;
}
/**
* Changes generated methods to have empty implementations.
*
* Methods in generated aggregates not supplied in a closures map or
* base class are given 'default' implementations. The implementation
* will normally throw an UnsupportedOperationException
* but setting this boolean will leave it empty.
*
* @param emptyMethods true if you want generated methods to be empty
*/
public void setEmptyMethods(boolean emptyMethods) {
this.emptyMethods = emptyMethods;
}
public ClassLoader getOverride() {
return override;
}
public void setOverride(ClassLoader override) {
this.override = override;
}
public Object instantiateAggregateFromBaseClass(Class clazz) {
return instantiateAggregateFromBaseClass((Map)null, clazz);
}
public Object instantiateAggregateFromBaseClass(Map map, Class clazz) {
return instantiateAggregateFromBaseClass(map, clazz, null);
}
public Object instantiateAggregateFromBaseClass(Closure cl, Class clazz) {
Map m = new HashMap();
m.put("*", cl);
return instantiateAggregateFromBaseClass(m, clazz, null);
}
public Object instantiateAggregateFromBaseClass(Map map, Class clazz, Object[] constructorArgs) {
return instantiateAggregate(map, null, clazz, constructorArgs);
}
public Object instantiateAggregateFromInterface(Class clazz) {
return instantiateAggregateFromInterface(null, clazz);
}
public Object instantiateAggregateFromInterface(Map map, Class clazz) {
List interfaces = new ArrayList();
interfaces.add(clazz);
return instantiateAggregate(map, interfaces);
}
public Object instantiateAggregate(List interfaces) {
return instantiateAggregate(null, interfaces);
}
public Object instantiateAggregate(Map closureMap, List interfaces) {
return instantiateAggregate(closureMap, interfaces, null);
}
public Object instantiateAggregate(Map closureMap, List interfaces, Class clazz) {
return instantiateAggregate(closureMap, interfaces, clazz, null);
}
public Object instantiateAggregate(Map closureMap, List interfaces, Class clazz, Object[] constructorArgs) {
Map map = new HashMap();
if (closureMap != null) {
map = closureMap;
}
List interfacesToImplement = new ArrayList();
if (interfaces != null) {
interfacesToImplement = interfaces;
}
Class baseClass = GroovyObjectSupport.class;
if (clazz != null) {
baseClass = clazz;
}
boolean hasArgs = constructorArgs != null && constructorArgs.length > 0;
String name = shortName(baseClass.getName()) + "_groovyProxy";
StringBuffer buffer = new StringBuffer();
// add class header and fields
buffer.append("class ").append(name);
if (clazz != null) {
buffer.append(" extends ").append(baseClass.getName());
}
for (int i = 0; i < interfacesToImplement.size(); i++) {
Class thisInterface = (Class) interfacesToImplement.get(i);
if (i == 0) {
buffer.append(" implements ");
} else {
buffer.append(", ");
}
buffer.append(thisInterface.getName());
}
buffer.append(" {\n").append(" private closureMap\n ");
// add constructor
buffer.append(name).append("(map");
if (hasArgs) {
buffer.append(", args");
}
buffer.append(") {\n");
buffer.append(" super(");
if (hasArgs) {
buffer.append("*args");
}
buffer.append(")\n");
buffer.append(" this.closureMap = map\n");
buffer.append(" }\n");
// add overwriting methods
Map selectedMethods = new HashMap();
List publicAndProtectedMethods = getInheritedMethods(baseClass, new ArrayList());
boolean closureIndicator = map.containsKey("*");
for (Method method : publicAndProtectedMethods) {
if (method.getName().indexOf('$') != -1
|| Modifier.isFinal(method.getModifiers())
|| ConversionHandler.isCoreObjectMethod(method)
|| containsEquivalentMethod(selectedMethods.values(), method))
continue;
if (map.containsKey(method.getName()) || closureIndicator) {
selectedMethods.put(method.getName(), method);
addOverridingMapCall(buffer, method, closureIndicator);
}
}
// add interface methods
List interfaceMethods = new ArrayList();
for (int i = 0; i < interfacesToImplement.size(); i++) {
Class thisInterface = (Class) interfacesToImplement.get(i);
getInheritedMethods(thisInterface, interfaceMethods);
}
for (int i = 0; i < interfaceMethods.size(); i++) {
Method method = (Method) interfaceMethods.get(i);
if (!containsEquivalentMethod(publicAndProtectedMethods, method)) {
selectedMethods.put(method.getName(), method);
addMapOrDummyCall(map, buffer, method);
}
}
// add leftover methods from the map
for (Iterator iterator = map.keySet().iterator(); iterator.hasNext();) {
String methodName = (String) iterator.next();
if (methodName.indexOf('$') != -1 || methodName.indexOf('*') != -1)
continue;
if (selectedMethods.keySet().contains(methodName)) continue;
addNewMapCall(buffer, methodName);
}
// end class
buffer.append("}\n").append("new ").append(name);
buffer.append("(map");
if (hasArgs) {
buffer.append(", constructorArgs");
}
buffer.append(")");
Binding binding = new Binding();
binding.setVariable("map", map);
binding.setVariable("constructorArgs", constructorArgs);
ClassLoader cl = override != null ? override : baseClass.getClassLoader();
if (clazz == null && interfacesToImplement.size() > 0) {
Class c = (Class) interfacesToImplement.get(0);
cl = c.getClassLoader();
}
GroovyShell shell = new GroovyShell(cl, binding);
if (debug)
System.out.println("proxy source:\n------------------\n" + buffer.toString() + "\n------------------");
try {
return shell.evaluate(buffer.toString());
} catch (MultipleCompilationErrorsException err) {
throw new GroovyRuntimeException("Error creating proxy: " + err.getMessage());
}
}
public Object instantiateDelegate(Object delegate) {
return instantiateDelegate(null, delegate);
}
public Object instantiateDelegate(List interfaces, Object delegate) {
return instantiateDelegate(null, interfaces, delegate);
}
public Object instantiateDelegate(Map closureMap, List interfaces, Object delegate) {
return instantiateDelegateWithBaseClass(closureMap, interfaces, delegate, null);
}
public Object instantiateDelegateWithBaseClass(Map closureMap, List interfaces, Object delegate) {
return instantiateDelegateWithBaseClass(closureMap, interfaces, delegate, delegate.getClass());
}
public Object instantiateDelegateWithBaseClass(Map closureMap, List interfaces, Object delegate, Class baseClass) {
String name = shortName(delegate.getClass().getName()) + "_delegateProxy";
return instantiateDelegateWithBaseClass(closureMap, interfaces, delegate, baseClass, name);
}
public Object instantiateDelegateWithBaseClass(Map closureMap, List interfaces, Object delegate, Class baseClass, String name) {
Map map = new HashMap();
if (closureMap != null) {
map = closureMap;
}
List selectedMethods = new ArrayList();
List interfacesToImplement = new ArrayList();
if (interfaces != null) {
interfacesToImplement = interfaces;
}
StringBuffer buffer = new StringBuffer();
// add class header and fields
buffer.append("import org.codehaus.groovy.runtime.InvokerHelper\nclass ").append(name);
if (baseClass != null) {
buffer.append(" extends ").append(baseClass.getName());
}
for (int i = 0; i < interfacesToImplement.size(); i++) {
Class thisInterface = (Class) interfacesToImplement.get(i);
if (i == 0) {
buffer.append(" implements ");
} else {
buffer.append(", ");
}
buffer.append(thisInterface.getName());
}
buffer.append(" {\n").append(" private delegate\n").append(" private closureMap\n ");
// add constructor
buffer.append(name).append("(map, delegate) {\n");
buffer.append(" this.closureMap = map\n");
buffer.append(" this.delegate = delegate\n");
buffer.append(" }\n");
// add interface methods
List interfaceMethods = new ArrayList();
for (int i = 0; i < interfacesToImplement.size(); i++) {
Class thisInterface = (Class) interfacesToImplement.get(i);
getInheritedMethods(thisInterface, interfaceMethods);
}
for (int i = 0; i < interfaceMethods.size(); i++) {
Method method = (Method) interfaceMethods.get(i);
if (!containsEquivalentMethod(objectMethods, method) &&
!containsEquivalentMethod(groovyObjectMethods, method)) {
selectedMethods.add(method.getName());
addWrappedCall(buffer, method, map);
}
}
List additionalMethods = getInheritedMethods(delegate.getClass(), new ArrayList());
for (int i = 0; i < additionalMethods.size(); i++) {
Method method = (Method) additionalMethods.get(i);
if (method.getName().indexOf('$') != -1)
continue;
if (!containsEquivalentMethod(interfaceMethods, method) &&
!containsEquivalentMethod(objectMethods, method) &&
!containsEquivalentMethod(groovyObjectMethods, method)) {
selectedMethods.add(method.getName());
addWrappedCall(buffer, method, map);
}
}
// add leftover methods from the map
for (Iterator iterator = map.keySet().iterator(); iterator.hasNext();) {
String methodName = (String) iterator.next();
if (selectedMethods.contains(methodName)) continue;
addNewMapCall(buffer, methodName);
}
// end class
buffer.append("}\n").append("new ").append(name);
buffer.append("(map, delegate)");
Binding binding = new Binding();
binding.setVariable("map", map);
binding.setVariable("delegate", delegate);
ClassLoader cl = override != null ? override : delegate.getClass().getClassLoader();
GroovyShell shell = new GroovyShell(cl, binding);
if (debug)
System.out.println("proxy source:\n------------------\n" + buffer.toString() + "\n------------------");
try {
return shell.evaluate(buffer.toString());
} catch (MultipleCompilationErrorsException err) {
throw new GroovyRuntimeException("Error creating proxy: " + err.getMessage());
}
}
private void addWrappedCall(StringBuffer buffer, Method method, Map map) {
if (map.containsKey(method.getName())) {
addOverridingMapCall(buffer, method, false);
} else {
Class[] parameterTypes = addMethodPrefix(buffer, method);
addWrappedMethodBody(buffer, method, parameterTypes);
addMethodSuffix(buffer);
}
}
private boolean containsEquivalentMethod(Collection publicAndProtectedMethods, Method candidate) {
for (Method method : publicAndProtectedMethods) {
if (candidate.getName().equals(method.getName()) &&
candidate.getReturnType().equals(method.getReturnType()) &&
hasMatchingParameterTypes(candidate, method)) {
return true;
}
}
return false;
}
private boolean hasMatchingParameterTypes(Method method, Method candidate) {
Class[] candidateParamTypes = candidate.getParameterTypes();
Class[] methodParamTypes = method.getParameterTypes();
if (candidateParamTypes.length != methodParamTypes.length) return false;
for (int i = 0; i < methodParamTypes.length; i++) {
if (!candidateParamTypes[i].equals(methodParamTypes[i])) return false;
}
return true;
}
private List getInheritedMethods(Class baseClass, List methods) {
methods.addAll(DefaultGroovyMethods.toList(baseClass.getMethods()));
Class currentClass = baseClass;
while (currentClass != null) {
Method[] protectedMethods = currentClass.getDeclaredMethods();
for (int i = 0; i < protectedMethods.length; i++) {
Method method = protectedMethods[i];
if (method.getName().indexOf('$') != -1)
continue;
if (Modifier.isProtected(method.getModifiers()) && !containsEquivalentMethod(methods, method))
methods.add(method);
}
currentClass = currentClass.getSuperclass();
}
return methods;
}
private void addNewMapCall(StringBuffer buffer, String methodName) {
buffer.append(" def ").append(methodName).append("(Object[] args) {\n")
.append(" this.@closureMap['").append(methodName).append("'] (*args)\n }\n");
}
private void addOverridingMapCall(StringBuffer buffer, Method method, boolean closureIndicator) {
Class[] parameterTypes = addMethodPrefix(buffer, method);
addMethodBody(buffer, closureIndicator ? "*" : method.getName(), parameterTypes);
addMethodSuffix(buffer);
}
private void addMapOrDummyCall(Map map, StringBuffer buffer, Method method) {
Class[] parameterTypes = addMethodPrefix(buffer, method);
if (map.containsKey(method.getName())) {
addMethodBody(buffer, method.getName(), parameterTypes);
} else if (!emptyMethods) {
addUnsupportedBody(buffer);
}
addMethodSuffix(buffer);
}
private void addUnsupportedBody(StringBuffer buffer) {
buffer.append("throw new UnsupportedOperationException()");
}
private Class[] addMethodPrefix(StringBuffer buffer, Method method) {
buffer.append(" ").append(getSimpleName(method.getReturnType()))
.append(" ").append(method.getName()).append("(");
Class[] parameterTypes = method.getParameterTypes();
for (int parameterTypeIndex = 0; parameterTypeIndex < parameterTypes.length; parameterTypeIndex++) {
Class parameter = parameterTypes[parameterTypeIndex];
if (parameterTypeIndex != 0) {
buffer.append(", ");
}
buffer.append(getSimpleName(parameter)).append(" ")
.append("p").append(parameterTypeIndex);
}
buffer.append(") { ");
return parameterTypes;
}
private void addMethodBody(StringBuffer buffer, String method, Class[] parameterTypes) {
buffer.append("this.@closureMap['").append(method).append("'] (");
for (int j = 0; j < parameterTypes.length; j++) {
if (j != 0) {
buffer.append(", ");
}
buffer.append("p").append(j);
}
buffer.append(")");
}
private void addWrappedMethodBody(StringBuffer buffer, Method method, Class[] parameterTypes) {
buffer.append("\n Object[] args = [");
for (int j = 0; j < parameterTypes.length; j++) {
if (j != 0) {
buffer.append(", ");
}
buffer.append("p").append(j);
}
buffer.append("]\n ");
buffer.append("InvokerHelper.invokeMethod(delegate, '").append(method.getName()).append("', args)\n");
}
private void addMethodSuffix(StringBuffer buffer) {
buffer.append(" }\n");
}
/**
* TODO once we switch to Java 1.5 bt default, use Class#getSimpleName() directly
*
* @param c the class of which we want the readable simple name
* @return the readable simple name
*/
public String getSimpleName(Class c) {
if (c.isArray()) {
int dimension = 0;
Class componentClass = c;
while (componentClass.isArray()) {
componentClass = componentClass.getComponentType();
dimension++;
}
return componentClass.getName().replaceAll("\\$", "\\.") +
DefaultGroovyMethods.multiply("[]", Integer.valueOf(dimension));
} else {
return c.getName().replaceAll("\\$", "\\.");
}
}
public String shortName(String name) {
int index = name.lastIndexOf('.');
if (index == -1) return name;
return name.substring(index + 1, name.length());
}
private static void setMetaClass(final MetaClass metaClass) {
final MetaClass newMetaClass = new DelegatingMetaClass(metaClass) {
/* (non-Javadoc)
* @see groovy.lang.MetaClass#invokeStaticMethod(java.lang.Object, java.lang.String, java.lang.Object[])
*/
public Object invokeStaticMethod(Object object, String methodName, Object[] arguments) {
return InvokerHelper.invokeMethod(INSTANCE, methodName, arguments);
}
};
GroovySystem.getMetaClassRegistry().setMetaClass(ProxyGenerator.class, newMetaClass);
}
}