namepreservingrunnable.java

mina是以Java实现的一个开源的网络程序框架

/*
 * 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.mina.util;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A {@link Runnable} wrapper that preserves the name of the thread after the runnable is
 * complete (for {@link Runnable}s that change the name of the Thread they use.)
 *
 * @author The Apache MINA Project ([e-mail])
 * @version $Rev: 446581 $, $Date: 2006-09-15 11:36:12Z $,
 */
public class NamePreservingRunnable implements Runnable {
    private final Logger logger = LoggerFactory.getLogger(NamePreservingRunnable.class);

    /** The runnable name */
    private final String newName;
    
    /** The runnable task */
    private final Runnable runnable;

    /**
     * Creates a new instance of NamePreservingRunnable.
     *
     * @param runnable The underlying runnable
     * @param newName The runnable's name
     */
    public NamePreservingRunnable(Runnable runnable, String newName) {
        this.runnable = runnable;
        this.newName = newName;
    }

    /**
     * Run the runnable after having renamed the current thread's name 
     * to the new name. When the runnable has completed, set back the 
     * current thread name back to its origin. 
     */
    public void run() {
        Thread currentThread = Thread.currentThread();
        String oldName = currentThread.getName();

        if (newName != null) {
            setName(currentThread, newName);
        }

        try {
            runnable.run();
        } finally {
            setName(currentThread, oldName);
        }
    }

    /**
     * Wraps {@link Thread#setName(String)} to catch a possible {@link Exception}s such as
     * {@link SecurityException} in sandbox environments, such as applets
     */
    private void setName(Thread thread, String name) {
        try {
            thread.setName(name);
        } catch (SecurityException se) {
            if (logger.isWarnEnabled()) {
                logger.warn("Failed to set the thread name.", se);
            }
        }
    }
}