代码备忘录

 
List 迭代
private final List<Entry> entries = new CopyOnWriteArrayList<Entry>();

for (ListIterator<Entry> i = entries.listIterator(); i.hasNext();) {
            Entry base = i.next();
            if (base.getName().equals(baseName)) {
                register(i.previousIndex(), new EntryImpl(name, filter));
                break;
            }
        }

确认一个参数是否为空
if (name == null) {
            throw new IllegalArgumentException("name");
        }

非静态内部类调为外部类
public void addAfter(String name, IoFilter filter) {
            DefaultIoFilterChainBuilder.this.addAfter(getName(), name, filter);
        }

异常处理类
public class DefaultExceptionMonitor extends ExceptionMonitor {
    private final static Logger LOGGER = LoggerFactory.getLogger(DefaultExceptionMonitor.class);

    /**
     * {@inheritDoc}
     */
    @Override
    public void exceptionCaught(Throwable cause) {
        if (cause instanceof Error) {
            throw (Error) cause;
        }

        LOGGER.warn("Unexpected exception.", cause);
    }
}

    异常单例句柄
    public abstract class ExceptionMonitor {
    private static ExceptionMonitor instance = new DefaultExceptionMonitor();

    /**
     * Returns the current exception monitor.
     */
    public static ExceptionMonitor getInstance() {
        return instance;
    }

    /**
     * Sets the uncaught exception monitor.  If <code>null</code> is specified,
     * the default monitor will be set.
     *
     * @param monitor A new instance of {@link DefaultExceptionMonitor} is set
     *                if <tt>null</tt> is specified.
     */
    public static void setInstance(ExceptionMonitor monitor) {
        if (monitor == null) {
            monitor = new DefaultExceptionMonitor();
        }
        
        instance = monitor;
    }

    /**
     * Invoked when there are any uncaught exceptions.
     * 
     * @param cause The caught exception
     */
    public abstract void exceptionCaught(Throwable cause);
}

 name thread
/*
 * 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 <a href="http://mina.apache.org">Apache MINA Project</a>
 */
public class NamePreservingRunnable implements Runnable {
    private final static 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);
            }
        }
    }
}

检查死锁

private void checkDeadLock() {
        // Only read / write / connect / write future can cause dead lock. 
        if (!(this instanceof CloseFuture || this instanceof WriteFuture ||
              this instanceof ReadFuture || this instanceof ConnectFuture)) {
            return;
        }
        
        // Get the current thread stackTrace. 
        // Using Thread.currentThread().getStackTrace() is the best solution,
        // even if slightly less efficient than doing a new Exception().getStackTrace(),
        // as internally, it does exactly the same thing. The advantage of using
        // this solution is that we may benefit some improvement with some
        // future versions of Java.
        StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();

        // Simple and quick check.
        for (StackTraceElement s: stackTrace) {
            if (AbstractPollingIoProcessor.class.getName().equals(s.getClassName())) {
                IllegalStateException e = new IllegalStateException( "t" );
                e.getStackTrace();
                throw new IllegalStateException(
                    "DEAD LOCK: " + IoFuture.class.getSimpleName() +
                    ".await() was invoked from an I/O processor thread.  " +
                    "Please use " + IoFutureListener.class.getSimpleName() +
                    " or configure a proper thread model alternatively.");
            }
        }

        // And then more precisely.
        for (StackTraceElement s: stackTrace) {
            try {
                Class<?> cls = DefaultIoFuture.class.getClassLoader().loadClass(s.getClassName());
                if (IoProcessor.class.isAssignableFrom(cls)) {
                    throw new IllegalStateException(
                        "DEAD LOCK: " + IoFuture.class.getSimpleName() +
                        ".await() was invoked from an I/O processor thread.  " +
                        "Please use " + IoFutureListener.class.getSimpleName() +
                        " or configure a proper thread model alternatively.");
                }
            } catch (Exception cnfe) {
                // Ignore
            }
        }
    }

评论

1 楼 lyy3323 2010-08-06  

这些有什么特殊的吗?