Java tutorial
/* * (C) Copyright 2006-2008 Nuxeo SAS (http://nuxeo.com/) and contributors. * * All rights reserved. This program and the accompanying materials * are made available under the terms of the GNU Lesser General Public License * (LGPL) version 2.1 which accompanies this distribution, and is available at * http://www.gnu.org/licenses/lgpl.html * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * Contributors: * bstefanescu * * $Id$ */ package org.nuxeo.runtime.service.proxy; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * Define wrappers for some methods on the target class. * * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a> */ public abstract class MethodsWrapper implements InvocationHandler { private static final Log log = LogFactory.getLog(MethodsWrapper.class); protected Map<Method, Method> methods; protected Class<?> wrapee; public MethodsWrapper(Class<?> klass) { methods = new ConcurrentHashMap<Method, Method>(); } protected void loadMethods() { methods = new ConcurrentHashMap<Method, Method>(); Method[] methods = getClass().getMethods(); for (Method method : methods) { if (method.getAnnotation(MethodWrapper.class) != null) { try { Method m = wrapee.getMethod(method.getName(), method.getParameterTypes()); this.methods.put(m, method); } catch (NoSuchMethodException e) { // malformed wrapper log.error(e, e); } } } } public Method getWrappedMethod(Method method) { if (methods == null) { synchronized (this) { if (methods == null) { loadMethods(); } } } return methods.get(method); } @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { Method m = methods.get(method); if (m == null) { return method.invoke(proxy, args); } else { return method.invoke(this, args); } } }