executorfilter.java

mina是以Java实现的一个开源的网络程序框架

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package org.apache.mina.filter.executor;

import java.util.EnumSet;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;

import org.apache.mina.core.filterchain.IoFilterAdapter;
import org.apache.mina.core.filterchain.IoFilterChain;
import org.apache.mina.core.filterchain.IoFilterEvent;
import org.apache.mina.core.session.IdleStatus;
import org.apache.mina.core.session.IoEventType;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.core.write.WriteRequest;

/**
 * A filter that forwards I/O events to {@link Executor} to enforce a certain
 * thread model while allowing the events per session to be processed
 * simultaneously. You can apply various thread model by inserting this filter
 * to a {@link IoFilterChain}.
 * 
 * <h2>Life Cycle Management</h2>
 * 
 * Please note that this filter doesn't manage the life cycle of the {@link Executor}.
 * If you created this filter using {@link #ExecutorFilter(Executor)} or similar
 * constructor that accepts an {@link Executor} that you've instantiated, you have
 * full control and responsibility of managing its life cycle (e.g. calling
 * {@link ExecutorService#shutdown()}.
 * <p> 
 * If you created this filter using convenience constructors like
 * {@link #ExecutorFilter(int)}, then you can shut down the executor by calling
 * {@link #destroy()} explicitly.
 * 
 * <h2>Event Ordering</h2>
 * 
 * All convenience constructors of this filter creates a new
 * {@link OrderedThreadPoolExecutor} instance.  Therefore, the order of event is
 * maintained like the following:
 * <ul>
 * <li>All event handler methods are called exclusively.
 *     (e.g. messageReceived and messageSent can't be invoked at the same time.)</li>
 * <li>The event order is never mixed up.
 *     (e.g. messageReceived is always invoked before sessionClosed or messageSent.)</li>
 * </ul>
 * However, if you specified other {@link Executor} instance in the constructor,
 * the order of events are not maintained at all.  This means more than one event
 * handler methods can be invoked at the same time with mixed order.  For example,
 * let's assume that messageReceived, messageSent, and sessionClosed events are
 * fired.
 * <ul>
 * <li>All event handler methods can be called simultaneously.
 *     (e.g. messageReceived and messageSent can be invoked at the same time.)</li>
 * <li>The event order can be mixed up.
 *     (e.g. sessionClosed or messageSent can be invoked before messageReceived
 *           is invoked.)</li>
 * </ul>
 * If you need to maintain the order of events per session, please specify an
 * {@link OrderedThreadPoolExecutor} instance or use the convenience constructors.
 * 
 * <h2>Selective Filtering</h2>
 * 
 * By default, all event types but <tt>sessionCreated</tt>, <tt>filterWrite</tt>,
 * <tt>filterClose</tt> and <tt>filterSetTrafficMask</tt> are submitted to the
 * underlying executor, which is most common setting.
 * <p>
 * If you want to submit only a certain set of event types, you can specify them
 * in the constructor.  For example, you could configure a thread pool for
 * write operation for the maximum performance:
 * <pre><code>
 * IoService service = ...;
 * DefaultIoFilterChainBuilder chain = service.getFilterChain();
 * 
 * chain.addLast("codec", new ProtocolCodecFilter(...));
 * // Use one thread pool for most events.
 * chain.addLast("executor1", new ExecutorFilter());
 * // and another dedicated thread pool for 'filterWrite' events.
 * chain.addLast("executor2", new ExecutorFilter(IoEventType.WRITE));
 * </code></pre>
 * 
 * <h2>Preventing {@link OutOfMemoryError}</h2>
 * 
 * Please refer to {@link IoEventQueueThrottle}, which is specified as
 * a parameter of the convenience constructors.
 * 
 * @author The Apache MINA Project ([e-mail])
 * @version $Rev: 762171 $, $Date: 2009-04-06 00:03:59 +0200 (Mon, 06 Apr 2009) $
 * 
 * @see OrderedThreadPoolExecutor
 * @see UnorderedThreadPoolExecutor
 * @org.apache.xbean.XBean
 */
public class ExecutorFilter extends IoFilterAdapter {
    /** The list of handled events */
    private EnumSet<IoEventType> eventTypes;
    
    /** The associated executor */
    private Executor executor;
    
    /** A flag set if the executor can be managed */ 
    private boolean manageableExecutor;
    
    /** The default pool size */
    private static final int DEFAULT_MAX_POOL_SIZE = 16;
    
    /** The number of thread to create at startup */
    private static final int BASE_THREAD_NUMBER = 0;
    
    /** The default KeepAlive time, in seconds */
    private static final long DEFAULT_KEEPALIVE_TIME = 30;
    
    /** 
     * A set of flags used to tell if the Executor has been created 
     * in the constructor or passed as an argument. In the second case, 
     * the executor state can be managed.
     **/
    private static final boolean MANAGEABLE_EXECUTOR = true;
    private static final boolean NOT_MANAGEABLE_EXECUTOR = false;
    
    /** A list of default EventTypes to be handled by the executor */
    private static IoEventType[] DEFAULT_EVENT_SET = new IoEventType[] {
        IoEventType.EXCEPTION_CAUGHT,
        IoEventType.MESSAGE_RECEIVED, 
        IoEventType.MESSAGE_SENT,
        IoEventType.SESSION_CLOSED, 
        IoEventType.SESSION_IDLE,
        IoEventType.SESSION_OPENED
    };
    

    /**
     * (Convenience constructor) Creates a new instance with a new
     * {@link OrderedThreadPoolExecutor}, no thread in the pool, and a 
     * maximum of 16 threads in the pool. All the event will be handled 
     * by this default executor.
     */
    public ExecutorFilter() {
        // Create a new default Executor
        Executor executor = createDefaultExecutor(
            BASE_THREAD_NUMBER,
            DEFAULT_MAX_POOL_SIZE,
            DEFAULT_KEEPALIVE_TIME,
            TimeUnit.SECONDS,
            Executors.defaultThreadFactory(),
            null);
        
        // Initialize the filter
        init(executor, MANAGEABLE_EXECUTOR, DEFAULT_EVENT_SET);
    }
    
    /**
     * (Convenience constructor) Creates a new instance with a new
     * {@link OrderedThreadPoolExecutor}, no thread in the pool, but 
     * a maximum of threads in the pool is given. All the event will be handled 
     * by this default executor.
     * 
     * @param maximumPoolSize The maximum pool size
     */
    public ExecutorFilter(int maximumPoolSize) {
        // Create a new default Executor
        Executor executor = createDefaultExecutor(
            BASE_THREAD_NUMBER,
            maximumPoolSize,
            DEFAULT_KEEPALIVE_TIME,
            TimeUnit.SECONDS,
            Executors.defaultThreadFactory(),
            null);
        
        // Initialize the filter
        init(executor, MANAGEABLE_EXECUTOR, DEFAULT_EVENT_SET);
    }
    
    /**
     * (Convenience constructor) Creates a new instance with a new
     * {@link OrderedThreadPoolExecutor}, a number of thread to start with, a  
     * maximum of threads the pool can contain. All the event will be handled 
     * by this default executor.
     *
     * @param corePoolSize The initial pool size
     * @param maximumPoolSize The maximum pool size
     */
    public ExecutorFilter(int corePoolSize, int maximumPoolSize) {
        // Create a new default Executor
        Executor executor = createDefaultExecutor(
            corePoolSize,
            maximumPoolSize,
            DEFAULT_KEEPALIVE_TIME,
            TimeUnit.SECONDS,
            Executors.defaultThreadFactory(),
            null);
        
        // Initialize the filter
        init(executor, MANAGEABLE_EXECUTOR, DEFAULT_EVENT_SET);
    }
    
    /**
     * (Convenience constructor) Creates a new instance with a new
     * {@link OrderedThreadPoolExecutor}.
     * 
     * @param corePoolSize The initial pool size
     * @param maximumPoolSize The maximum pool size
     * @param keepAliveTime Default duration for a thread
     * @param unit Time unit used for the keepAlive value
     */
    public ExecutorFilter(int corePoolSize, int maximumPoolSize, long keepAliveTime, 
            TimeUnit unit) {
        // Create a new default Executor
        Executor executor = createDefaultExecutor(
            corePoolSize,
            maximumPoolSize,
            keepAliveTime,
            unit,
            Executors.defaultThreadFactory(),
            null);
        
        // Initialize the filter
        init(executor, MANAGEABLE_EXECUTOR, DEFAULT_EVENT_SET);
    }

    /**
     * (Convenience constructor) Creates a new instance with a new
     * {@link OrderedThreadPoolExecutor}.
     * 
     * @param corePoolSize The initial pool size
     * @param maximumPoolSize The maximum pool size
     * @param keepAliveTime Default duration for a thread
     * @param unit Time unit used for the keepAlive value
     * @param queueHandler The queue used to store events
     */
    public ExecutorFilter(
            int corePoolSize, int maximumPoolSize, 
            long keepAliveTime, TimeUnit unit,
            IoEventQueueHandler queueHandler) {
        // Create a new default Executor
        Executor executor = createDefaultExecutor(
            corePoolSize,
            maximumPoolSize,
            keepAliveTime,
            unit,
            Executors.defaultThreadFactory(),
            queueHandler);
        
        // Initialize the filter
        init(executor, MANAGEABLE_EXECUTOR, DEFAULT_EVENT_SET);
    }

    /**
     * (Convenience constructor) Creates a new instance with a new
     * {@link OrderedThreadPoolExecutor}.
     * 
     * @param corePoolSize The initial pool size
     * @param maximumPoolSize The maximum pool size
     * @param keepAliveTime Default duration for a thread
     * @param unit Time unit used for the keepAlive value
     * @param threadFactory The factory used to create threads
     */
    public ExecutorFilter(
            int corePoolSize, int maximumPoolSize, 
            long keepAliveTime, TimeUnit unit,
            ThreadFactory threadFactory) {
        // Create a new default Executor
        Executor executor = createDefaultExecutor(
            corePoolSize,
            maximumPoolSize,
            keepAliveTime,
            unit,
            threadFactory,
            null);
        
        // Initialize the filter
        init(executor, MANAGEABLE_EXECUTOR, DEFAULT_EVENT_SET);
    }

    /**
     * (Convenience constructor) Creates a new instance with a new
     * {@link OrderedThreadPoolExecutor}.
     * 
     * @param corePoolSize The initial pool size
     * @param maximumPoolSize The maximum pool size
     * @param keepAliveTime Default duration for a thread
     * @param unit Time unit used for the keepAlive value
     * @param threadFactory The factory used to create threads
     * @param queueHandler The queue used to store events
     */
    public ExecutorFilter(
            int corePoolSize, int maximumPoolSize, 
            long keepAliveTime, TimeUnit unit,
            ThreadFactory threadFactory, IoEventQueueHandler queueHandler) {
        // Create a new default Executor
        Executor executor = new OrderedThreadPoolExecutor(corePoolSize, maximumPoolSize, keepAliveTime, unit, threadFactory, queueHandler);
        
        // Initialize the filter
        init(executor, MANAGEABLE_EXECUTOR, DEFAULT_EVENT_SET);
    }

    /**
     * (Convenience constructor) Creates a new instance with a new
     * {@link OrderedThreadPoolExecutor}.
     * 
     * @param eventTypes The event for which the executor will be used
     */
    public ExecutorFilter(IoEventType... eventTypes) {
        // Create a new default Executor
        Executor executor = createDefaultExecutor(
            BASE_THREAD_NUMBER,
            DEFAULT_MAX_POOL_SIZE,
            DEFAULT_KEEPALIVE_TIME,
            TimeUnit.SECONDS,
            Executors.defaultThreadFactory(),
            null);
        
        // Initialize the filter
        init(executor, MANAGEABLE_EXECUTOR, eventTypes);
    }
    
    /**
     * (Convenience constructor) Creates a new instance with a new
     * {@link OrderedThreadPoolExecutor}.
     * 
     * @param maximumPoolSize The maximum pool size
     * @param eventTypes The event for which the executor will be used
     */
    public ExecutorFilter(int maximumPoolSize, IoEventType... eventTypes) {
        // Create a new default Executor
        Executor executor = createDefaultExecutor(
            BASE_THREAD_NUMBER,
            maximumPoolSize,
            DEFAULT_KEEPALIVE_TIME,
            TimeUnit.SECONDS,
            Executors.defaultThreadFactory(),
            null);
        
        // Initialize the filter
        init(executor, MANAGEABLE_EXECUTOR, eventTypes);
    }
    
    /**
     * (Convenience constructor) Creates a new instance with a new
     * {@link OrderedThreadPoolExecutor}.
     * 
     * @param corePoolSize The initial pool size
     * @param maximumPoolSize The maximum pool size
     * @param eventTypes The event for which the executor will be used
     */
    public ExecutorFilter(int corePoolSize, int maximumPoolSize, IoEventType... eventTypes) {
        // Create a new default Executor
        Executor executor = createDefaultExecutor(