org.cloudata.core.common.testhelper.FaultInjectionProxy.java Source code

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Here is the source code for org.cloudata.core.common.testhelper.FaultInjectionProxy.java

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/**
 * 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.cloudata.core.common.testhelper;

import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.cloudata.core.common.conf.CloudataConf;

public class FaultInjectionProxy {
    static final Log LOG = LogFactory.getLog(FaultInjectionProxy.class);
    static Object fmLock = new Object();
    static FaultManager fm = null;

    // by sangchul    . ? Type safe .
    @SuppressWarnings("unchecked")
    public static <T> T wrap(Object body, Class<? extends T> c) {
        synchronized (fmLock) {
            if (fm == null) {
                try {
                    fm = FaultManager.create(new CloudataConf());
                } catch (IOException e) {
                    LOG.warn("Fail to create fault manager", e);
                }
            }
        }
        return (T) Proxy.newProxyInstance(c.getClassLoader(), new Class<?>[] { c },
                new FaultInjectionHandler(body));
    }

    static class FaultInjectionHandler implements InvocationHandler {
        Object body;

        public FaultInjectionHandler(Object body) {
            this.body = body;
        }

        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
            Object ret = null;
            Fault fault = null;

            synchronized (fmLock) {
                fault = fm.getFault(proxy.getClass(), method.getName());
            }

            if (fault != null) {
                fault.playBeforeInvoke(body);
                try {
                    ret = method.invoke(body, args);
                } finally {
                    fault.playAfterInvoke(body);
                }
            } else {
                ret = method.invoke(body, args);
            }

            return ret;
        }
    }
}