/*
* JBoss, Home of Professional Open Source
* Copyright 2008, Red Hat, Inc. and/or its affiliates, and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* 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.jboss.weld.bean.proxy;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.security.AccessController;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.Set;
import javax.enterprise.inject.spi.Bean;
import org.jboss.classfilewriter.AccessFlag;
import org.jboss.classfilewriter.ClassFile;
import org.jboss.classfilewriter.ClassMethod;
import org.jboss.classfilewriter.code.CodeAttribute;
import org.jboss.weld.exceptions.WeldException;
import org.jboss.weld.injection.FieldInjectionPoint;
import org.jboss.weld.injection.ParameterInjectionPoint;
import org.jboss.weld.injection.attributes.WeldInjectionPointAttributes;
import org.jboss.weld.interceptor.util.proxy.TargetInstanceProxy;
import org.jboss.weld.logging.BeanLogger;
import org.jboss.weld.security.GetDeclaredMethodAction;
import org.jboss.weld.security.GetDeclaredMethodsAction;
import org.jboss.weld.util.bytecode.BytecodeUtils;
import org.jboss.weld.util.bytecode.DescriptorUtils;
import org.jboss.weld.util.bytecode.MethodInformation;
import org.jboss.weld.util.bytecode.RuntimeMethodInformation;
import org.jboss.weld.util.bytecode.StaticMethodInformation;
/**
* This special proxy factory is mostly used for abstract decorators. When a
* delegate field is injected, the abstract methods directly invoke the
* corresponding method on the delegate. All other cases forward the calls to
* the {@link BeanInstance} for further processing.
*
* @author David Allen
* @author Stuart Douglas
*/
public class DecoratorProxyFactory<T> extends ProxyFactory<T> {
public static final String PROXY_SUFFIX = "DecoratorProxy";
private static final String INIT_MH_METHOD_NAME = "_initMH";
private final WeldInjectionPointAttributes<?, ?> delegateInjectionPoint;
private final Field delegateField;
public DecoratorProxyFactory(String contextId, Class<T> proxyType, WeldInjectionPointAttributes<?, ?> delegateInjectionPoint, Bean<?> bean) {
super(contextId, proxyType, Collections.<Type>emptySet(), bean);
this.delegateInjectionPoint = delegateInjectionPoint;
if (delegateInjectionPoint instanceof FieldInjectionPoint<?, ?>) {
delegateField = (Field) ((FieldInjectionPoint<?, ?>) delegateInjectionPoint).getMember();
} else {
delegateField = null;
}
}
/**
* calls _initMH on the method handler and then stores the result in the
* methodHandler field as then new methodHandler
*/
private void addHandlerInitializerMethod(ClassFile proxyClassType, ClassMethod staticConstructor) throws Exception {
ClassMethod classMethod = proxyClassType.addMethod(AccessFlag.PRIVATE, INIT_MH_METHOD_NAME, DescriptorUtils.VOID_CLASS_DESCRIPTOR, LJAVA_LANG_OBJECT);
final CodeAttribute b = classMethod.getCodeAttribute();
b.aload(0);
StaticMethodInformation methodInfo = new StaticMethodInformation(INIT_MH_METHOD_NAME, new Class[] { Object.class }, void.class,
classMethod.getClassFile().getName());
invokeMethodHandler(classMethod, methodInfo, false, DEFAULT_METHOD_RESOLVER, staticConstructor);
b.checkcast(MethodHandler.class);
b.putfield(classMethod.getClassFile().getName(), METHOD_HANDLER_FIELD_NAME, DescriptorUtils.classToStringRepresentation(MethodHandler.class));
b.returnInstruction();
BeanLogger.LOG.createdMethodHandlerInitializerForDecoratorProxy(getBeanType());
}
@Override
protected void addAdditionalInterfaces(Set<Class<?>> interfaces) {
interfaces.add(DecoratorProxy.class);
}
@Override
protected void addMethodsFromClass(ClassFile proxyClassType, ClassMethod staticConstructor) {
Method initializerMethod = null;
int delegateParameterPosition = -1;
if (delegateInjectionPoint instanceof ParameterInjectionPoint<?, ?>) {
ParameterInjectionPoint<?, ?> parameterIP = (ParameterInjectionPoint<?, ?>) delegateInjectionPoint;
if (parameterIP.getMember() instanceof Method) {
initializerMethod = ((Method) parameterIP.getMember());
delegateParameterPosition = parameterIP.getAnnotated().getPosition();
}
}
try {
if (delegateParameterPosition >= 0) {
addHandlerInitializerMethod(proxyClassType, staticConstructor);
}
Class<?> cls = getBeanType();
Set<Method> methods = new LinkedHashSet<Method>();
decoratorMethods(cls, methods);
for (Method method : methods) {
MethodInformation methodInfo = new RuntimeMethodInformation(method);
if (!method.getDeclaringClass().getName().equals("java.lang.Object") || method.getName().equals("toString")) {
if ((delegateParameterPosition >= 0) && (initializerMethod.equals(method))) {
createDelegateInitializerCode(proxyClassType.addMethod(method), methodInfo, delegateParameterPosition);
}
// exclude bridge methods
if (Modifier.isAbstract(method.getModifiers())) {
createAbstractMethodCode(proxyClassType.addMethod(method), methodInfo, staticConstructor);
}
}
}
} catch (Exception e) {
throw new WeldException(e);
}
}
private void decoratorMethods(Class<?> cls, Set<Method> all) {
if (cls == null) {
return;
}
all.addAll(Arrays.asList(AccessController.doPrivileged(new GetDeclaredMethodsAction(cls))));
decoratorMethods(cls.getSuperclass(), all);
// by now we should have all declared methods, let's only add the missing ones
for (Class<?> ifc : cls.getInterfaces()) {
Method[] methods = ifc.getMethods();
for (Method m : methods) {
boolean isEqual = false;
for (Method a : all) {
if (isEqual(m, a)) {
isEqual = true;
break;
}
}
if (!isEqual) {
all.add(m);
}
}
}
}
// m is more generic than a
private static boolean isEqual(Method m, Method a) {
if (m.getName().equals(a.getName()) && m.getParameterTypes().length == a.getParameterTypes().length && m.getReturnType().isAssignableFrom(a.getReturnType())) {
for (int i = 0; i < m.getParameterTypes().length; i++) {
if (!(m.getParameterTypes()[i].isAssignableFrom(a.getParameterTypes()[i]))) {
return false;
}
}
return true;
}
return false;
}
@Override
protected String getProxyNameSuffix() {
return PROXY_SUFFIX;
}
private void createAbstractMethodCode(ClassMethod classMethod, MethodInformation method, ClassMethod staticConstructor) {
if ((delegateField != null) && (!Modifier.isPrivate(delegateField.getModifiers()))) {
// Call the corresponding method directly on the delegate
final CodeAttribute b = classMethod.getCodeAttribute();
// load the delegate field
b.aload(0);
b.getfield(classMethod.getClassFile().getName(), delegateField.getName(), DescriptorUtils.classToStringRepresentation(delegateField.getType()));
// load the parameters
b.loadMethodParameters();
// invoke the delegate method
b.invokeinterface(delegateField.getType().getName(), method.getName(), method.getDescriptor());
// return the value if applicable
b.returnInstruction();
} else {
if (!Modifier.isPrivate(method.getMethod().getModifiers())) {
// if it is a parameter injection point we need to initialize the
// injection point then handle the method with the method handler
// this is slightly different to a normal method handler call, as we pass
// in a TargetInstanceBytecodeMethodResolver. This resolver uses the
// method handler to call getTargetClass to get the correct class type to
// resolve the method with, and then resolves this method
invokeMethodHandler(classMethod, method, true, TargetInstanceBytecodeMethodResolver.INSTANCE, staticConstructor);
} else {
// if the delegate is private we need to use the method handler
createInterceptorBody(classMethod, method, staticConstructor);
}
}
}
/**
* When creates the delegate initializer code when the delegate is injected
* into a method.
* <p/>
* super initializer method is called first, and then _initMH is called
*
* @param initializerMethodInfo
* @param delegateParameterPosition
* @return
*/
private void createDelegateInitializerCode(ClassMethod classMethod, MethodInformation initializerMethodInfo, int delegateParameterPosition) {
final CodeAttribute b = classMethod.getCodeAttribute();
// we need to push all the parameters on the stack to call the corresponding
// superclass arguments
b.aload(0); // load this
int localVariables = 1;
int actualDelegateParameterPosition = 0;
for (int i = 0; i < initializerMethodInfo.getMethod().getParameterTypes().length; ++i) {
if (i == delegateParameterPosition) {
// figure out the actual position of the delegate in the local
// variables
actualDelegateParameterPosition = localVariables;
}
Class<?> type = initializerMethodInfo.getMethod().getParameterTypes()[i];
BytecodeUtils.addLoadInstruction(b, DescriptorUtils.classToStringRepresentation(type), localVariables);
if (type == long.class || type == double.class) {
localVariables = localVariables + 2;
} else {
localVariables++;
}
}
b.invokespecial(classMethod.getClassFile().getSuperclass(), initializerMethodInfo.getName(), initializerMethodInfo.getDescriptor());
// if this method returns a value it is now sitting on top of the stack
// we will leave it there are return it later
// now we need to call _initMH
b.aload(0); // load this
b.aload(actualDelegateParameterPosition); // load the delegate
b.invokevirtual(classMethod.getClassFile().getName(), INIT_MH_METHOD_NAME, "(" + LJAVA_LANG_OBJECT + ")" + DescriptorUtils.VOID_CLASS_DESCRIPTOR);
// return the object from the top of the stack that we got from calling
// the superclass method earlier
b.returnInstruction();
}
protected static class TargetInstanceBytecodeMethodResolver implements BytecodeMethodResolver {
private static final String JAVA_LANG_CLASS_CLASS_NAME = "java.lang.Class";
public void getDeclaredMethod(ClassMethod classMethod, String declaringClass, String methodName, String[] parameterTypes, ClassMethod staticConstructor) {
// get the correct class type to use to resolve the method
MethodInformation methodInfo = new StaticMethodInformation("getTargetClass", new String[0], LJAVA_LANG_CLASS, TargetInstanceProxy.class.getName());
invokeMethodHandler(classMethod, methodInfo, false, DEFAULT_METHOD_RESOLVER, staticConstructor);
CodeAttribute code = classMethod.getCodeAttribute();
code.checkcast("java/lang/Class");
// now we have the class on the stack
code.ldc(methodName);
// now we need to load the parameter types into an array
code.iconst(parameterTypes.length);
code.anewarray(JAVA_LANG_CLASS_CLASS_NAME);
for (int i = 0; i < parameterTypes.length; ++i) {
code.dup(); // duplicate the array reference
code.iconst(i);
// now load the class object
String type = parameterTypes[i];
BytecodeUtils.pushClassType(code, type);
// and store it in the array
code.aastore();
}
code.invokestatic(GetDeclaredMethodAction.class.getName(), "of", "(Ljava/lang/Class;Ljava/lang/String;[Ljava/lang/Class;)Lorg/jboss/weld/security/GetDeclaredMethodAction;");
code.invokestatic(AccessController.class.getName(), "doPrivileged", "(Ljava/security/PrivilegedAction;)Ljava/lang/Object;");
code.checkcast(Method.class);
}
static final TargetInstanceBytecodeMethodResolver INSTANCE = new TargetInstanceBytecodeMethodResolver();
}
}