001 /**
002 * Copyright (C) 2009 Erik Putrycz <erik.putrycz@gmail.com>
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017 package net.ep.db4o.factories;
018
019 import java.lang.reflect.Constructor;
020 import java.lang.reflect.InvocationHandler;
021 import java.lang.reflect.Method;
022 import java.util.HashMap;
023 import java.util.Map;
024
025 public class FactoryInvocationHandler implements InvocationHandler {
026
027 private Map<Method, Constructor<?>> _constructors = new HashMap<Method, Constructor<?>>();
028 private Factories _factories;
029
030 public FactoryInvocationHandler(Class<?> factory, Class<?> targetType, Class<?> realType, Factories basicFactories) {
031 for (Method method:factory.getDeclaredMethods()) {
032 Constructor<?> cons = findConstructor(method, realType);
033 if (cons == null)
034 throw new InvalidFactoryException("No matching constructor found in " + targetType.getName() + " for method " + method.getName());
035 _constructors.put(method, cons);
036 }
037 _factories = basicFactories;
038 }
039
040 private Constructor<?> findConstructor(Method main, Class<?> targetType) {
041 for (Constructor<?> cons:targetType.getDeclaredConstructors()) {
042 cons.setAccessible(true);
043 if (cons.getParameterTypes() != null && main.getParameterTypes() != null) {
044 if (cons.getParameterTypes().length == main.getParameterTypes().length) {
045 boolean found = true;
046 for (int il = 0;il < cons.getParameterTypes().length;il++) {
047 found = found && cons.getParameterTypes()[il] == main.getParameterTypes()[il];
048 }
049 if (found)
050 return cons;
051 }
052 } else {
053 if (main.getParameterTypes() == null)
054 return cons;
055 }
056 }
057 return null;
058 }
059
060 public Object invoke(Object proxy, Method method, Object[] args)
061 throws Throwable {
062 Object inst = _constructors.get(method).newInstance(args);
063 _factories.onNewInstance(inst);
064 return inst;
065 }
066
067 }