Java tutorial
/* * Copyright 2010-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"). * You may not use this file except in compliance with the License. * A copy of the License is located at * * http://aws.amazon.com/apache2.0 * * or in the "license" file accompanying this file. This file 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 com.amazonaws.http.conn; import java.lang.reflect.InvocationHandler; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.lang.reflect.Proxy; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.http.conn.ClientConnectionManager; import org.apache.http.conn.ClientConnectionRequest; import org.apache.http.pool.ConnPoolControl; public class ClientConnectionManagerFactory { private static final Log log = LogFactory.getLog(ClientConnectionManagerFactory.class); /** * Returns a wrapped instance of {@link ClientConnectionManager} * to capture the necessary performance metrics. * @param orig the target instance to be wrapped */ public static ClientConnectionManager wrap(ClientConnectionManager orig) { if (orig instanceof Wrapped) throw new IllegalArgumentException(); final Class<?>[] interfaces; if (orig instanceof ConnPoolControl) { interfaces = new Class<?>[] { ClientConnectionManager.class, ConnPoolControl.class, Wrapped.class }; } else { interfaces = new Class<?>[] { ClientConnectionManager.class, Wrapped.class }; } return (ClientConnectionManager) Proxy.newProxyInstance( // https://github.com/aws/aws-sdk-java/pull/48#issuecomment-29454423 ClientConnectionManagerFactory.class.getClassLoader(), interfaces, new Handler(orig)); } /** * The handler behind the dynamic proxy for {@link ClientConnectionManager} * so that the any returned instance of {@link ClientConnectionRequest} can * further wrapped for capturing performance metrics. */ private static class Handler implements InvocationHandler { private final ClientConnectionManager orig; Handler(ClientConnectionManager real) { this.orig = real; } @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { try { Object ret = method.invoke(orig, args); return ret instanceof ClientConnectionRequest ? ClientConnectionRequestFactory.wrap((ClientConnectionRequest) ret) : ret; } catch (InvocationTargetException e) { log.debug("", e); throw e.getCause(); } } } }