| /* |
| * 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.apache.commons.proxy2.javassist; |
| |
| import java.lang.ref.WeakReference; |
| import java.lang.reflect.Method; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.WeakHashMap; |
| |
| import javassist.CannotCompileException; |
| import javassist.CtClass; |
| import javassist.CtConstructor; |
| import javassist.CtMethod; |
| |
| import org.apache.commons.lang3.ArrayUtils; |
| import org.apache.commons.lang3.ObjectUtils; |
| import org.apache.commons.proxy2.Invocation; |
| import org.apache.commons.proxy2.ProxyUtils; |
| |
| /** |
| * A <a href="http://www.jboss.org/products/javassist">Javassist</a>-based {@link Invocation} implementation. This class |
| * actually serves as the superclass for all <a href="http://www.jboss.org/products/javassist">Javassist</a>-based |
| * method invocations. Subclasses are dynamically created to deal with specific interface methods (they're hard-wired). |
| * |
| * @since 1.0 |
| */ |
| public abstract class JavassistInvocation implements Invocation |
| { |
| //****************************************************************************************************************** |
| // Fields |
| //****************************************************************************************************************** |
| |
| private static WeakHashMap<ClassLoader, Map<String, WeakReference<Class<?>>>> loaderToClassCache |
| = new WeakHashMap<ClassLoader, Map<String, WeakReference<Class<?>>>>(); |
| |
| /** The proxy object */ |
| private final Object proxy; |
| |
| /** The target object */ |
| private final Object target; |
| |
| /** The invoked method */ |
| private final Method method; |
| |
| /** The method arguments */ |
| private final Object[] arguments; |
| |
| //****************************************************************************************************************** |
| // Static Methods |
| //****************************************************************************************************************** |
| |
| private static String createCastExpression(Class<?> type, String objectToCast) |
| { |
| if (!type.isPrimitive()) |
| { |
| return "( " + ProxyUtils.getJavaClassName(type) + " )" + objectToCast; |
| } |
| else |
| { |
| return "( ( " + ProxyUtils.getWrapperClass(type).getName() + " )" + objectToCast + " )." + type.getName() |
| + "Value()"; |
| } |
| } |
| |
| private static Class<?> createInvocationClass(ClassLoader classLoader, Method interfaceMethod) |
| throws CannotCompileException |
| { |
| final CtClass ctClass = JavassistUtils.createClass(getSimpleName(interfaceMethod.getDeclaringClass()) + "_" |
| + interfaceMethod.getName() + "_invocation", JavassistInvocation.class); |
| final CtConstructor constructor = new CtConstructor(JavassistUtils.resolve(new Class[] { Object.class, |
| Object.class, Method.class, Object[].class }), ctClass); |
| constructor.setBody("{\n\tsuper($$);\n}"); |
| ctClass.addConstructor(constructor); |
| final CtMethod proceedMethod = new CtMethod(JavassistUtils.resolve(Object.class), "proceed", |
| JavassistUtils.resolve(new Class[0]), ctClass); |
| final Class<?>[] argumentTypes = interfaceMethod.getParameterTypes(); |
| final StringBuilder proceedBody = new StringBuilder("{\n"); |
| if (!Void.TYPE.equals(interfaceMethod.getReturnType())) |
| { |
| proceedBody.append("\treturn "); |
| if (interfaceMethod.getReturnType().isPrimitive()) |
| { |
| proceedBody.append("new "); |
| proceedBody.append(ProxyUtils.getWrapperClass(interfaceMethod.getReturnType()).getName()); |
| proceedBody.append("( "); |
| } |
| } |
| else |
| { |
| proceedBody.append("\t"); |
| } |
| proceedBody.append("( ("); |
| proceedBody.append(ProxyUtils.getJavaClassName(interfaceMethod.getDeclaringClass())); |
| proceedBody.append(" )getTarget() )."); |
| proceedBody.append(interfaceMethod.getName()); |
| proceedBody.append("("); |
| for (int i = 0; i < argumentTypes.length; ++i) |
| { |
| final Class<?> argumentType = argumentTypes[i]; |
| proceedBody.append(createCastExpression(argumentType, "getArguments()[" + i + "]")); |
| if (i != argumentTypes.length - 1) |
| { |
| proceedBody.append(", "); |
| } |
| } |
| if (!Void.TYPE.equals(interfaceMethod.getReturnType()) && interfaceMethod.getReturnType().isPrimitive()) |
| { |
| proceedBody.append(") );\n"); |
| } |
| else |
| { |
| proceedBody.append(");\n"); |
| } |
| if (Void.TYPE.equals(interfaceMethod.getReturnType())) |
| { |
| proceedBody.append("\treturn null;\n"); |
| } |
| proceedBody.append("}"); |
| final String body = proceedBody.toString(); |
| proceedMethod.setBody(body); |
| ctClass.addMethod(proceedMethod); |
| |
| @SuppressWarnings("deprecation") |
| final Class<?> invocationClass = ctClass.toClass(classLoader); |
| return invocationClass; |
| } |
| |
| private static Map<String, WeakReference<Class<?>>> getClassCache(ClassLoader classLoader) |
| { |
| Map<String, WeakReference<Class<?>>> cache = loaderToClassCache.get(classLoader); |
| if (cache == null) |
| { |
| cache = new HashMap<String, WeakReference<Class<?>>>(); |
| loaderToClassCache.put(classLoader, cache); |
| } |
| return cache; |
| } |
| |
| /** |
| * Returns a method invocation class specifically coded to invoke the supplied interface method. |
| * |
| * @param classLoader |
| * the classloader to use |
| * @param interfaceMethod |
| * the interface method |
| * @return a method invocation class specifically coded to invoke the supplied interface method |
| * @throws CannotCompileException |
| * if a compilation error occurs |
| */ |
| static synchronized Class<?> getMethodInvocationClass(ClassLoader classLoader, Method interfaceMethod) |
| throws CannotCompileException |
| { |
| final Map<String, WeakReference<Class<?>>> classCache = getClassCache(classLoader); |
| final String key = toClassCacheKey(interfaceMethod); |
| final WeakReference<Class<?>> invocationClassRef = classCache.get(key); |
| Class<?> invocationClass; |
| if (invocationClassRef == null) |
| { |
| invocationClass = createInvocationClass(classLoader, interfaceMethod); |
| classCache.put(key, new WeakReference<Class<?>>(invocationClass)); |
| } |
| else |
| { |
| synchronized (invocationClassRef) |
| { |
| invocationClass = invocationClassRef.get(); |
| if (invocationClass == null) |
| { |
| invocationClass = createInvocationClass(classLoader, interfaceMethod); |
| classCache.put(key, new WeakReference<Class<?>>(invocationClass)); |
| } |
| } |
| } |
| return invocationClass; |
| } |
| |
| private static String getSimpleName(Class<?> c) |
| { |
| final String name = c.getName(); |
| final int ndx = name.lastIndexOf('.'); |
| return ndx == -1 ? name : name.substring(ndx + 1); |
| } |
| |
| private static String toClassCacheKey(Method method) |
| { |
| return String.valueOf(method); |
| } |
| |
| //****************************************************************************************************************** |
| // Constructors |
| //****************************************************************************************************************** |
| |
| protected JavassistInvocation(Object proxy, Object target, Method method, Object[] arguments) |
| { |
| this.proxy = proxy; |
| this.target = target; |
| this.method = method; |
| this.arguments = ObjectUtils.defaultIfNull(ArrayUtils.clone(arguments), ProxyUtils.EMPTY_ARGUMENTS); |
| } |
| |
| //****************************************************************************************************************** |
| // Invocation Implementation |
| //****************************************************************************************************************** |
| protected final Object getTarget() |
| { |
| return target; |
| } |
| |
| @Override |
| public Object[] getArguments() |
| { |
| return arguments; |
| } |
| |
| @Override |
| public Method getMethod() |
| { |
| return method; |
| } |
| |
| @Override |
| public Object getProxy() |
| { |
| return proxy; |
| } |
| } |