org.apache.mina.core.session.AbstractIoSession - MINA 2.0.13 源码

/*
 *  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.core.session;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.SocketAddress;
import java.nio.channels.FileChannel;
import java.util.Iterator;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;

import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.file.DefaultFileRegion;
import org.apache.mina.core.file.FilenameFileRegion;
import org.apache.mina.core.filterchain.IoFilterChain;
import org.apache.mina.core.future.CloseFuture;
import org.apache.mina.core.future.DefaultCloseFuture;
import org.apache.mina.core.future.DefaultReadFuture;
import org.apache.mina.core.future.DefaultWriteFuture;
import org.apache.mina.core.future.IoFutureListener;
import org.apache.mina.core.future.ReadFuture;
import org.apache.mina.core.future.WriteFuture;
import org.apache.mina.core.service.AbstractIoService;
import org.apache.mina.core.service.IoAcceptor;
import org.apache.mina.core.service.IoHandler;
import org.apache.mina.core.service.IoProcessor;
import org.apache.mina.core.service.IoService;
import org.apache.mina.core.service.TransportMetadata;
import org.apache.mina.core.write.DefaultWriteRequest;
import org.apache.mina.core.write.WriteException;
import org.apache.mina.core.write.WriteRequest;
import org.apache.mina.core.write.WriteRequestQueue;
import org.apache.mina.core.write.WriteTimeoutException;
import org.apache.mina.core.write.WriteToClosedSessionException;
import org.apache.mina.util.ExceptionMonitor;

/**
 * Base implementation of {@link IoSession}.
 *
 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
 */
public abstract class AbstractIoSession implements IoSession {
    /** The associated handler */
    private final IoHandler handler;

    /** The session config */
    protected IoSessionConfig config;

    /** The service which will manage this session */
    private final IoService service;

    private static final AttributeKey READY_READ_FUTURES_KEY = new AttributeKey(AbstractIoSession.class,
            "readyReadFutures");

    private static final AttributeKey WAITING_READ_FUTURES_KEY = new AttributeKey(AbstractIoSession.class,
            "waitingReadFutures");

    private static final IoFutureListener<CloseFuture> SCHEDULED_COUNTER_RESETTER = new IoFutureListener<CloseFuture>() {
        public void operationComplete(CloseFuture future) {
            AbstractIoSession session = (AbstractIoSession) future.getSession();
            session.scheduledWriteBytes.set(0);
            session.scheduledWriteMessages.set(0);
            session.readBytesThroughput = 0;
            session.readMessagesThroughput = 0;
            session.writtenBytesThroughput = 0;
            session.writtenMessagesThroughput = 0;
        }
    };

    /**
     * An internal write request object that triggers session close.
     *
     * @see #writeRequestQueue
     */
    private static final WriteRequest CLOSE_REQUEST = new DefaultWriteRequest(new Object());

    private final Object lock = new Object();

    private IoSessionAttributeMap attributes;

    private WriteRequestQueue writeRequestQueue;

    private WriteRequest currentWriteRequest;

    /** The Session creation's time */
    private final long creationTime;

    /** An id generator guaranteed to generate unique IDs for the session */
    private static AtomicLong idGenerator = new AtomicLong(0);

    /** The session ID */
    private long sessionId;

    /**
     * A future that will be set 'closed' when the connection is closed.
     */
    private final CloseFuture closeFuture = new DefaultCloseFuture(this);

    private volatile boolean closing;

    // traffic control
    private boolean readSuspended = false;

    private boolean writeSuspended = false;

    // Status variables
    private final AtomicBoolean scheduledForFlush = new AtomicBoolean();

    private final AtomicInteger scheduledWriteBytes = new AtomicInteger();

    private final AtomicInteger scheduledWriteMessages = new AtomicInteger();

    private long readBytes;

    private long writtenBytes;

    private long readMessages;

    private long writtenMessages;

    private long lastReadTime;

    private long lastWriteTime;

    private long lastThroughputCalculationTime;

    private long lastReadBytes;

    private long lastWrittenBytes;

    private long lastReadMessages;

    private long lastWrittenMessages;

    private double readBytesThroughput;

    private double writtenBytesThroughput;

    private double readMessagesThroughput;

    private double writtenMessagesThroughput;

    private AtomicInteger idleCountForBoth = new AtomicInteger();

    private AtomicInteger idleCountForRead = new AtomicInteger();

    private AtomicInteger idleCountForWrite = new AtomicInteger();

    private long lastIdleTimeForBoth;

    private long lastIdleTimeForRead;

    private long lastIdleTimeForWrite;

    private boolean deferDecreaseReadBuffer = true;

    /**
     * Create a Session for a service
     *
     * @param service the Service for this session
     */
    protected AbstractIoSession(IoService service) {
        this.service = service;
        this.handler = service.getHandler();

        // Initialize all the Session counters to the current time
        long currentTime = System.currentTimeMillis();
        creationTime = currentTime;
        lastThroughputCalculationTime = currentTime;
        lastReadTime = currentTime;
        lastWriteTime = currentTime;
        lastIdleTimeForBoth = currentTime;
        lastIdleTimeForRead = currentTime;
        lastIdleTimeForWrite = currentTime;

        // TODO add documentation
        closeFuture.addListener(SCHEDULED_COUNTER_RESETTER);

        // Set a new ID for this session
        sessionId = idGenerator.incrementAndGet();
    }

    /**
     * {@inheritDoc}
     *
     * We use an AtomicLong to guarantee that the session ID are unique.
     */
    public final long getId() {
        return sessionId;
    }

    /**
     * @return The associated IoProcessor for this session
     */
    public abstract IoProcessor getProcessor();

    /**
     * {@inheritDoc}
     */
    public final boolean isConnected() {
        return !closeFuture.isClosed();
    }

    /**
     * {@inheritDoc}
     */
    public boolean isActive() {
        // Return true by default
        return true;
    }

    /**
     * {@inheritDoc}
     */
    public final boolean isClosing() {
        return closing || closeFuture.isClosed();
    }

    /**
     * {@inheritDoc}
     */
    public boolean isSecured() {
        // Always false...
        return false;
    }

    /**
     * {@inheritDoc}
     */
    public final CloseFuture getCloseFuture() {
        return closeFuture;
    }

    /**
     * Tells if the session is scheduled for flushed
     *
     * @return true if the session is scheduled for flush
     */
    public final boolean isScheduledForFlush() {
        return scheduledForFlush.get();
    }

    /**
     * Schedule the session for flushed
     */
    public final void scheduledForFlush() {
        scheduledForFlush.set(true);
    }

    /**
     * Change the session's status : it's not anymore scheduled for flush
     */
    public final void unscheduledForFlush() {
        scheduledForFlush.set(false);
    }

    /**
     * Set the scheduledForFLush flag. As we may have concurrent access to this
     * flag, we compare and set it in one call.
     *
     * @param schedule
     *            the new value to set if not already set.
     * @return true if the session flag has been set, and if it wasn't set
     *         already.
     */
    public final boolean setScheduledForFlush(boolean schedule) {
        if (schedule) {
            // If the current tag is set to false, switch it to true,
            // otherwise, we do nothing but return false : the session
            // is already scheduled for flush
            return scheduledForFlush.compareAndSet(false, schedule);
        }

        scheduledForFlush.set(schedule);
        return true;
    }

    /**
     * {@inheritDoc}
     */
    public final CloseFuture close(boolean rightNow) {
        if (rightNow) {
            return closeNow();
        } else {
            return closeOnFlush();
        }
    }

    /**
     * {@inheritDoc}
     */
    public final CloseFuture close() {
        try {
            closeNow();
        } finally {
            return closeFuture;
        }
    }

    /**
     * {@inheritDoc}
     */
    public final CloseFuture closeOnFlush() {
        if (!isClosing()) {
            getWriteRequestQueue().offer(this, CLOSE_REQUEST);
            getProcessor().flush(this);
            return closeFuture;
        } else {
            return closeFuture;
        }
    }

    /**
     * {@inheritDoc}
     */
    public final CloseFuture closeNow() {
        synchronized (lock) {
            if (isClosing()) {
                return closeFuture;
            }

            closing = true;
        }

        getFilterChain().fireFilterClose();

        return closeFuture;
    }

    /**
     * {@inheritDoc}
     */
    public IoHandler getHandler() {
        return handler;
    }

    /**
     * {@inheritDoc}
     */
    public IoSessionConfig getConfig() {
        return config;
    }

    /**
     * {@inheritDoc}
     */
    public final ReadFuture read() {
        if (!getConfig().isUseReadOperation()) {
            throw new IllegalStateException("useReadOperation is not enabled.");
        }

        Queue<ReadFuture> readyReadFutures = getReadyReadFutures();
        ReadFuture future;
        synchronized (readyReadFutures) {
            future = readyReadFutures.poll();
            if (future != null) {
                if (future.isClosed()) {
                    // Let other readers get notified.
                    readyReadFutures.offer(future);
                }
            } else {
                future = new DefaultReadFuture(this);
                getWaitingReadFutures().offer(future);
            }
        }

        return future;
    }

    /**
     * Associates a message to a ReadFuture
     *
     * @param message the message to associate to the ReadFuture
     *
     */
    public final void offerReadFuture(Object message) {
        newReadFuture().setRead(message);
    }

    /**
     * Associates a failure to a ReadFuture
     *
     * @param exception the exception to associate to the ReadFuture
     */
    public final void offerFailedReadFuture(Throwable exception) {
        newReadFuture().setException(exception);
    }

    /**
     * Inform the ReadFuture that the session has been closed
     */
    public final void offerClosedReadFuture() {
        Queue<ReadFuture> readyReadFutures = getReadyReadFutures();

        synchronized (readyReadFutures) {
            newReadFuture().setClosed();
        }
    }

    /**
     * @return a readFuture get from the waiting ReadFuture
     */
    private ReadFuture newReadFuture() {
        Queue<ReadFuture> readyReadFutures = getReadyReadFutures();
        Queue<ReadFuture> waitingReadFutures = getWaitingReadFutures();
        ReadFuture future;

        synchronized (readyReadFutures) {
            future = waitingReadFutures.poll();

            if (future == null) {
                future = new DefaultReadFuture(this);
                readyReadFutures.offer(future);
            }
        }

        return future;
    }

    /**
     * @return a queue of ReadFuture
     */
    private Queue<ReadFuture> getReadyReadFutures() {
        Queue<ReadFuture> readyReadFutures = (Queue<ReadFuture>) getAttribute(READY_READ_FUTURES_KEY);

        if (readyReadFutures == null) {
            readyReadFutures = new ConcurrentLinkedQueue<ReadFuture>();

            Queue<ReadFuture> oldReadyReadFutures = (Queue<ReadFuture>) setAttributeIfAbsent(READY_READ_FUTURES_KEY,
                    readyReadFutures);

            if (oldReadyReadFutures != null) {
                readyReadFutures = oldReadyReadFutures;
            }
        }

        return readyReadFutures;
    }

    /**
     * @return the queue of waiting ReadFuture
     */
    private Queue<ReadFuture> getWaitingReadFutures() {
        Queue<ReadFuture> waitingReadyReadFutures = (Queue<ReadFuture>) getAttribute(WAITING_READ_FUTURES_KEY);

        if (waitingReadyReadFutures == null) {
            waitingReadyReadFutures = new ConcurrentLinkedQueue<ReadFuture>();

            Queue<ReadFuture> oldWaitingReadyReadFutures = (Queue<ReadFuture>) setAttributeIfAbsent(
                    WAITING_READ_FUTURES_KEY, waitingReadyReadFutures);

            if (oldWaitingReadyReadFutures != null) {
                waitingReadyReadFutures = oldWaitingReadyReadFutures;
            }
        }

        return waitingReadyReadFutures;
    }

    /**
     * {@inheritDoc}
     */
    public WriteFuture write(Object message) {
        return write(message, null);
    }

    /**
     * {@inheritDoc}
     */
    public WriteFuture write(Object message, SocketAddress remoteAddress) {
        if (message == null) {
            throw new IllegalArgumentException("Trying to write a null message : not allowed");
        }

        // We can't send a message to a connected session if we don't have
        // the remote address
        if (!getTransportMetadata().isConnectionless() && (remoteAddress != null)) {
            throw new UnsupportedOperationException();
        }

        // If the session has been closed or is closing, we can't either
        // send a message to the remote side. We generate a future
        // containing an exception.
        if (isClosing() || !isConnected()) {
            WriteFuture future = new DefaultWriteFuture(this);
            WriteRequest request = new DefaultWriteRequest(message, future, remoteAddress);
            WriteException writeException = new WriteToClosedSessionException(request);
            future.setException(writeException);
            return future;
        }

        FileChannel openedFileChannel = null;

        // TODO: remove this code as soon as we use InputStream
        // instead of Object for the message.
        try {
            if ((message instanceof IoBuffer) && !((IoBuffer) message).hasRemaining()) {
                // Nothing to write : probably an error in the user code
                throw new IllegalArgumentException("message is empty. Forgot to call flip()?");
            } else if (message instanceof FileChannel) {
                FileChannel fileChannel = (FileChannel) message;
                message = new DefaultFileRegion(fileChannel, 0, fileChannel.size());
            } else if (message instanceof File) {
                File file = (File) message;
                openedFileChannel = new FileInputStream(file).getChannel();
                message = new FilenameFileRegion(file, openedFileChannel, 0, openedFileChannel.size());
            }
        } catch (IOException e) {
            ExceptionMonitor.getInstance().exceptionCaught(e);
            return DefaultWriteFuture.newNotWrittenFuture(this, e);
        }

        // Now, we can write the message. First, create a future
        WriteFuture writeFuture = new DefaultWriteFuture(this);
        WriteRequest writeRequest = new DefaultWriteRequest(message, writeFuture, remoteAddress);

        // Then, get the chain and inject the WriteRequest into it
        IoFilterChain filterChain = getFilterChain();
        filterChain.fireFilterWrite(writeRequest);

        // TODO : This is not our business ! The caller has created a
        // FileChannel,
        // he has to close it !
        if (openedFileChannel != null) {
            // If we opened a FileChannel, it needs to be closed when the write
            // has completed
            final FileChannel finalChannel = openedFileChannel;
            writeFuture.addListener(new IoFutureListener<WriteFuture>() {
                public void operationComplete(WriteFuture future) {
                    try {
                        finalChannel.close();
                    } catch (IOException e) {
                        ExceptionMonitor.getInstance().exceptionCaught(e);
                    }
                }
            });
        }

        // Return the WriteFuture.
        return writeFuture;
    }

    /**
     * {@inheritDoc}
     */
    public final Object getAttachment() {
        return getAttribute("");
    }

    /**
     * {@inheritDoc}
     */
    public final Object setAttachment(Object attachment) {
        return setAttribute("", attachment);
    }

    /**
     * {@inheritDoc}
     */
    public final Object getAttribute(Object key) {
        return getAttribute(key, null);
    }

    /**
     * {@inheritDoc}
     */
    public final Object getAttribute(Object key, Object defaultValue) {
        return attributes.getAttribute(this, key, defaultValue);
    }

    /**
     * {@inheritDoc}
     */
    public final Object setAttribute(Object key, Object value) {
        return attributes.setAttribute(this, key, value);
    }

    /**
     * {@inheritDoc}
     */
    public final Object setAttribute(Object key) {
        return setAttribute(key, Boolean.TRUE);
    }

    /**
     * {@inheritDoc}
     */
    public final Object setAttributeIfAbsent(Object key, Object value) {
        return attributes.setAttributeIfAbsent(this, key, value);
    }

    /**
     * {@inheritDoc}
     */
    public final Object setAttributeIfAbsent(Object key) {
        return setAttributeIfAbsent(key, Boolean.TRUE);
    }

    /**
     * {@inheritDoc}
     */
    public final Object removeAttribute(Object key) {
        return attributes.removeAttribute(this, key);
    }

    /**
     * {@inheritDoc}
     */
    public final boolean removeAttribute(Object key, Object value) {
        return attributes.removeAttribute(this, key, value);
    }

    /**
     * {@inheritDoc}
     */
    public final boolean replaceAttribute(Object key, Object oldValue, Object newValue) {
        return attributes.replaceAttribute(this, key, oldValue, newValue);
    }

    /**
     * {@inheritDoc}
     */
    public final boolean containsAttribute(Object key) {
        return attributes.containsAttribute(this, key);
    }

    /**
     * {@inheritDoc}
     */
    public final Set<Object> getAttributeKeys() {
        return attributes.getAttributeKeys(this);
    }

    /**
     * @return The map of attributes associated with the session
     */
    public final IoSessionAttributeMap getAttributeMap() {
        return attributes;
    }

    /**
     * Set the map of attributes associated with the session
     *
     * @param attributes The Map of attributes
     */
    public final void setAttributeMap(IoSessionAttributeMap attributes) {
        this.attributes = attributes;
    }

    /**
     * Create a new close aware write queue, based on the given write queue.
     *
     * @param writeRequestQueue The write request queue
     */
    public final void setWriteRequestQueue(WriteRequestQueue writeRequestQueue) {
        this.writeRequestQueue = new CloseAwareWriteQueue(writeRequestQueue);
    }

    /**
     * {@inheritDoc}
     */
    public final void suspendRead() {
        readSuspended = true;
        if (isClosing() || !isConnected()) {
            return;
        }
        getProcessor().updateTrafficControl(this);
    }

    /**
     * {@inheritDoc}
     */
    public final void suspendWrite() {
        writeSuspended = true;
        if (isClosing() || !isConnected()) {
            return;
        }
        getProcessor().updateTrafficControl(this);
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public final void resumeRead() {
        readSuspended = false;
        if (isClosing() || !isConnected()) {
            return;
        }
        getProcessor().updateTrafficControl(this);
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public final void resumeWrite() {
        writeSuspended = false;
        if (isClosing() || !isConnected()) {
            return;
        }
        getProcessor().updateTrafficControl(this);
    }

    /**
     * {@inheritDoc}
     */
    public boolean isReadSuspended() {
        return readSuspended;
    }

    /**
     * {@inheritDoc}
     */
    public boolean isWriteSuspended() {
        return writeSuspended;
    }

    /**
     * {@inheritDoc}
     */
    public final long getReadBytes() {
        return readBytes;
    }

    /**
     * {@inheritDoc}
     */
    public final long getWrittenBytes() {
        return writtenBytes;
    }

    /**
     * {@inheritDoc}
     */
    public final long getReadMessages() {
        return readMessages;
    }

    /**
     * {@inheritDoc}
     */
    public final long getWrittenMessages() {
        return writtenMessages;
    }

    /**
     * {@inheritDoc}
     */
    public final double getReadBytesThroughput() {
        return readBytesThroughput;
    }

    /**
     * {@inheritDoc}
     */
    public final double getWrittenBytesThroughput() {
        return writtenBytesThroughput;
    }

    /**
     * {@inheritDoc}
     */
    public final double getReadMessagesThroughput() {
        return readMessagesThroughput;
    }

    /**
     * {@inheritDoc}
     */
    public final double getWrittenMessagesThroughput() {
        return writtenMessagesThroughput;
    }

    /**
     * {@inheritDoc}
     */
    public final void updateThroughput(long currentTime, boolean force) {
        int interval = (int) (currentTime - lastThroughputCalculationTime);

        long minInterval = getConfig().getThroughputCalculationIntervalInMillis();

        if (((minInterval == 0) || (interval < minInterval)) && !force) {
            return;
        }

        readBytesThroughput = (readBytes - lastReadBytes) * 1000.0 / interval;
        writtenBytesThroughput = (writtenBytes - lastWrittenBytes) * 1000.0 / interval;
        readMessagesThroughput = (readMessages - lastReadMessages) * 1000.0 / interval;
        writtenMessagesThroughput = (writtenMessages - lastWrittenMessages) * 1000.0 / interval;

        lastReadBytes = readBytes;
        lastWrittenBytes = writtenBytes;
        lastReadMessages = readMessages;
        lastWrittenMessages = writtenMessages;

        lastThroughputCalculationTime = currentTime;
    }

    /**
     * {@inheritDoc}
     */
    public final long getScheduledWriteBytes() {
        return scheduledWriteBytes.get();
    }

    /**
     * {@inheritDoc}
     */
    public final int getScheduledWriteMessages() {
        return scheduledWriteMessages.get();
    }

    /**
     * Set the number of scheduled write bytes
     *
     * @param byteCount The number of scheduled bytes for write
     */
    protected void setScheduledWriteBytes(int byteCount) {
        scheduledWriteBytes.set(byteCount);
    }

    /**
     * Set the number of scheduled write messages
     *
     * @param messages The number of scheduled messages for write
     */
    protected void setScheduledWriteMessages(int messages) {
        scheduledWriteMessages.set(messages);
    }

    /**
     * Increase the number of read bytes
     *
     * @param increment The number of read bytes
     * @param currentTime The current time
     */
    public final void increaseReadBytes(long increment, long currentTime) {
        if (increment <= 0) {
            return;
        }

        readBytes += increment;
        lastReadTime = currentTime;
        idleCountForBoth.set(0);
        idleCountForRead.set(0);

        if (getService() instanceof AbstractIoService) {
            ((AbstractIoService) getService()).getStatistics().increaseReadBytes(increment, currentTime);
        }
    }

    /**
     * Increase the number of read messages
     *
     * @param currentTime The current time
     */
    public final void increaseReadMessages(long currentTime) {
        readMessages++;
        lastReadTime = currentTime;
        idleCountForBoth.set(0);
        idleCountForRead.set(0);

        if (getService() instanceof AbstractIoService) {
            ((AbstractIoService) getService()).getStatistics().increaseReadMessages(currentTime);
        }
    }

    /**
     * Increase the number of written bytes
     *
     * @param increment The number of written bytes
     * @param currentTime The current time
     */
    public final void increaseWrittenBytes(int increment, long currentTime) {
        if (increment <= 0) {
            return;
        }

        writtenBytes += increment;
        lastWriteTime = currentTime;
        idleCountForBoth.set(0);
        idleCountForWrite.set(0);

        if (getService() instanceof AbstractIoService) {
            ((AbstractIoService) getService()).getStatistics().increaseWrittenBytes(increment, currentTime);
        }

        increaseScheduledWriteBytes(-increment);
    }

    /**
     * Increase the number of written messages
     *
     * @param request The written message
     * @param currentTime The current tile
     */
    public final void increaseWrittenMessages(WriteRequest request, long currentTime) {
        Object message = request.getMessage();

        if (message instanceof IoBuffer) {
            IoBuffer b = (IoBuffer) message;

            if (b.hasRemaining()) {
                return;
            }
        }

        writtenMessages++;
        lastWriteTime = currentTime;

        if (getService() instanceof AbstractIoService) {
            ((AbstractIoService) getService()).getStatistics().increaseWrittenMessages(currentTime);
        }

        decreaseScheduledWriteMessages();
    }

    /**
     * Increase the number of scheduled write bytes for the session
     *
     * @param increment The number of newly added bytes to write
     */
    public final void increaseScheduledWriteBytes(int increment) {
        scheduledWriteBytes.addAndGet(increment);
        if (getService() instanceof AbstractIoService) {
            ((AbstractIoService) getService()).getStatistics().increaseScheduledWriteBytes(increment);
        }
    }

    /**
     * Increase the number of scheduled message to write
     */
    public final void increaseScheduledWriteMessages() {
        scheduledWriteMessages.incrementAndGet();

        if (getService() instanceof AbstractIoService) {
            ((AbstractIoService) getService()).getStatistics().increaseScheduledWriteMessages();
        }
    }

    /**
     * Decrease the number of scheduled message written
     */
    private void decreaseScheduledWriteMessages() {
        scheduledWriteMessages.decrementAndGet();
        if (getService() instanceof AbstractIoService) {
            ((AbstractIoService) getService()).getStatistics().decreaseScheduledWriteMessages();
        }
    }

    /**
     * Decrease the counters of written messages and written bytes when a message has been written
     *
     * @param request The written message
     */
    public final void decreaseScheduledBytesAndMessages(WriteRequest request) {
        Object message = request.getMessage();

        if (message instanceof IoBuffer) {
            IoBuffer b = (IoBuffer) message;

            if (b.hasRemaining()) {
                increaseScheduledWriteBytes(-((IoBuffer) message).remaining());
            } else {
                decreaseScheduledWriteMessages();
            }
        } else {
            decreaseScheduledWriteMessages();
        }
    }

    /**
     * {@inheritDoc}
     */
    public final WriteRequestQueue getWriteRequestQueue() {
         if (writeRequestQueue == null) {
             throw new IllegalStateException();
         }

         return writeRequestQueue;
     }

     /**
      * {@inheritDoc}
      */
     public final WriteRequest getCurrentWriteRequest() {
         return currentWriteRequest;
     }

     /**
      * {@inheritDoc}
      */
     public final Object getCurrentWriteMessage() {
         WriteRequest req = getCurrentWriteRequest();

         if (req == null) {
             return null;
         }
         return req.getMessage();
     }

     /**
      * {@inheritDoc}
      */
     public final void setCurrentWriteRequest(WriteRequest currentWriteRequest) {
         this.currentWriteRequest = currentWriteRequest;
     }

     /**
      * Increase the ReadBuffer size (it will double)
      */
     public final void increaseReadBufferSize() {
         int newReadBufferSize = getConfig().getReadBufferSize() << 1;
         if (newReadBufferSize <= getConfig().getMaxReadBufferSize()) {
             getConfig().setReadBufferSize(newReadBufferSize);
         } else {
             getConfig().setReadBufferSize(getConfig().getMaxReadBufferSize());
         }

         deferDecreaseReadBuffer = true;
     }

     /**
      * Decrease the ReadBuffer size (it will be divided by a factor 2)
      */
     public final void decreaseReadBufferSize() {
         if (deferDecreaseReadBuffer) {
             deferDecreaseReadBuffer = false;
             return;
         }

         if (getConfig().getReadBufferSize() > getConfig().getMinReadBufferSize()) {
             getConfig().setReadBufferSize(getConfig().getReadBufferSize() >>> 1);
         }

         deferDecreaseReadBuffer = true;
     }

     /**
      * {@inheritDoc}
      */
     public final long getCreationTime() {
         return creationTime;
     }

     /**
      * {@inheritDoc}
      */
     public final long getLastIoTime() {
         return Math.max(lastReadTime, lastWriteTime);
     }

     /**
      * {@inheritDoc}
      */
     public final long getLastReadTime() {
         return lastReadTime;
     }

     /**
      * {@inheritDoc}
      */
     public final long getLastWriteTime() {
         return lastWriteTime;
     }

     /**
      * {@inheritDoc}
      */
     public final boolean isIdle(IdleStatus status) {
         if (status == IdleStatus.BOTH_IDLE) {
             return idleCountForBoth.get() > 0;
         }

         if (status == IdleStatus.READER_IDLE) {
             return idleCountForRead.get() > 0;
         }

         if (status == IdleStatus.WRITER_IDLE) {
             return idleCountForWrite.get() > 0;
         }

         throw new IllegalArgumentException("Unknown idle status: " + status);
     }

     /**
      * {@inheritDoc}
      */
     public final boolean isBothIdle() {
         return isIdle(IdleStatus.BOTH_IDLE);
     }

     /**
      * {@inheritDoc}
      */
     public final boolean isReaderIdle() {
         return isIdle(IdleStatus.READER_IDLE);
     }

     /**
      * {@inheritDoc}
      */
     public final boolean isWriterIdle() {
         return isIdle(IdleStatus.WRITER_IDLE);
     }

     /**
      * {@inheritDoc}
      */
     public final int getIdleCount(IdleStatus status) {
         if (getConfig().getIdleTime(status) == 0) {
             if (status == IdleStatus.BOTH_IDLE) {
                 idleCountForBoth.set(0);
             }

             if (status == IdleStatus.READER_IDLE) {
                 idleCountForRead.set(0);
             }

             if (status == IdleStatus.WRITER_IDLE) {
                 idleCountForWrite.set(0);
             }
         }

         if (status == IdleStatus.BOTH_IDLE) {
             return idleCountForBoth.get();
         }

         if (status == IdleStatus.READER_IDLE) {
             return idleCountForRead.get();
         }

         if (status == IdleStatus.WRITER_IDLE) {
             return idleCountForWrite.get();
         }

         throw new IllegalArgumentException("Unknown idle status: " + status);
     }

     /**
      * {@inheritDoc}
      */
     public final long getLastIdleTime(IdleStatus status) {
         if (status == IdleStatus.BOTH_IDLE) {
             return lastIdleTimeForBoth;
         }

         if (status == IdleStatus.READER_IDLE) {
             return lastIdleTimeForRead;
         }

         if (status == IdleStatus.WRITER_IDLE) {
             return lastIdleTimeForWrite;
         }

         throw new IllegalArgumentException("Unknown idle status: " + status);
     }

     /**
      * Increase the count of the various Idle counter
      *
      * @param status The current status
      * @param currentTime The current time
      */
     public final void increaseIdleCount(IdleStatus status, long currentTime) {
         if (status == IdleStatus.BOTH_IDLE) {
             idleCountForBoth.incrementAndGet();
             lastIdleTimeForBoth = currentTime;
         } else if (status == IdleStatus.READER_IDLE) {
             idleCountForRead.incrementAndGet();
             lastIdleTimeForRead = currentTime;
         } else if (status == IdleStatus.WRITER_IDLE) {
             idleCountForWrite.incrementAndGet();
             lastIdleTimeForWrite = currentTime;
         } else {
             throw new IllegalArgumentException("Unknown idle status: " + status);
         }
     }

     /**
      * {@inheritDoc}
      */
     public final int getBothIdleCount() {
         return getIdleCount(IdleStatus.BOTH_IDLE);
     }

     /**
      * {@inheritDoc}
      */
     public final long getLastBothIdleTime() {
         return getLastIdleTime(IdleStatus.BOTH_IDLE);
     }

     /**
      * {@inheritDoc}
      */
     public final long getLastReaderIdleTime() {
         return getLastIdleTime(IdleStatus.READER_IDLE);
     }

     /**
      * {@inheritDoc}
      */
     public final long getLastWriterIdleTime() {
         return getLastIdleTime(IdleStatus.WRITER_IDLE);
     }

     /**
      * {@inheritDoc}
      */
     public final int getReaderIdleCount() {
         return getIdleCount(IdleStatus.READER_IDLE);
     }

     /**
      * {@inheritDoc}
      */
     public final int getWriterIdleCount() {
         return getIdleCount(IdleStatus.WRITER_IDLE);
     }

     /**
      * {@inheritDoc}
      */
     public SocketAddress getServiceAddress() {
         IoService service = getService();
         if (service instanceof IoAcceptor) {
             return ((IoAcceptor) service).getLocalAddress();
         }

         return getRemoteAddress();
     }

     /**
      * {@inheritDoc}
      */
     @Override
     public final int hashCode() {
         return super.hashCode();
     }

     /**
      * {@inheritDoc} TODO This is a ridiculous implementation. Need to be
      * replaced.
      */
     @Override
     public final boolean equals(Object o) {
         return super.equals(o);
     }

     /**
      * {@inheritDoc}
      */
     @Override
     public String toString() {
         if (isConnected() || isClosing()) {
             String remote = null;
             String local = null;

             try {
                 remote = String.valueOf(getRemoteAddress());
             } catch (Exception e) {
                 remote = "Cannot get the remote address informations: " + e.getMessage();
             }

             try {
                 local = String.valueOf(getLocalAddress());
             } catch (Exception e) {
             }

             if (getService() instanceof IoAcceptor) {
                 return "(" + getIdAsString() + ": " + getServiceName() + ", server, " + remote + " => " + local + ')';
             }

             return "(" + getIdAsString() + ": " + getServiceName() + ", client, " + local + " => " + remote + ')';
         }

         return "(" + getIdAsString() + ") Session disconnected ...";
     }

     /**
      * Get the Id as a String
      */
     private String getIdAsString() {
         String id = Long.toHexString(getId()).toUpperCase();

         if (id.length() <= 8) {
             return "0x00000000".substring(0, 10 - id.length()) + id;
         } else {
             return "0x" + id;
         }
     }

     /**
      * TGet the Service name
      */
     private String getServiceName() {
         TransportMetadata tm = getTransportMetadata();
         if (tm == null) {
             return "null";
         }

         return tm.getProviderName() + ' ' + tm.getName();
     }

     /**
      * {@inheritDoc}
      */
     public IoService getService() {
         return service;
     }

     /**
      * Fires a {@link IoEventType#SESSION_IDLE} event to any applicable sessions
      * in the specified collection.
      *
      * @param sessions The sessions that are notified
      * @param currentTime the current time (i.e. {@link System#currentTimeMillis()})
      */
     public static void notifyIdleness(Iterator<? extends IoSession> sessions, long currentTime) {
         while (sessions.hasNext()) {
             IoSession session = sessions.next();

             if (!session.getCloseFuture().isClosed()) {
                 notifyIdleSession(session, currentTime);
             }
         }
     }

     /**
      * Fires a {@link IoEventType#SESSION_IDLE} event if applicable for the
      * specified {@code session}.
      *
      * @param session The session that is notified
      * @param currentTime the current time (i.e. {@link System#currentTimeMillis()})
      */
     public static void notifyIdleSession(IoSession session, long currentTime) {
         notifyIdleSession0(session, currentTime, session.getConfig().getIdleTimeInMillis(IdleStatus.BOTH_IDLE),
                 IdleStatus.BOTH_IDLE, Math.max(session.getLastIoTime(), session.getLastIdleTime(IdleStatus.BOTH_IDLE)));

         notifyIdleSession0(session, currentTime, session.getConfig().getIdleTimeInMillis(IdleStatus.READER_IDLE),
                 IdleStatus.READER_IDLE,
                 Math.max(session.getLastReadTime(), session.getLastIdleTime(IdleStatus.READER_IDLE)));

         notifyIdleSession0(session, currentTime, session.getConfig().getIdleTimeInMillis(IdleStatus.WRITER_IDLE),
                 IdleStatus.WRITER_IDLE,
                 Math.max(session.getLastWriteTime(), session.getLastIdleTime(IdleStatus.WRITER_IDLE)));

         notifyWriteTimeout(session, currentTime);
     }

     private static void notifyIdleSession0(IoSession session, long currentTime, long idleTime, IdleStatus status,
             long lastIoTime) {
         if ((idleTime > 0) && (lastIoTime != 0) && (currentTime - lastIoTime >= idleTime)) {
             session.getFilterChain().fireSessionIdle(status);
         }
     }

     private static void notifyWriteTimeout(IoSession session, long currentTime) {

         long writeTimeout = session.getConfig().getWriteTimeoutInMillis();
         if ((writeTimeout > 0) && (currentTime - session.getLastWriteTime() >= writeTimeout)
                 && !session.getWriteRequestQueue().isEmpty(session)) {
             WriteRequest request = session.getCurrentWriteRequest();
             if (request != null) {
                 session.setCurrentWriteRequest(null);
                 WriteTimeoutException cause = new WriteTimeoutException(request);
                 request.getFuture().setException(cause);
                 session.getFilterChain().fireExceptionCaught(cause);
                 // WriteException is an IOException, so we close the session.
                 session.close(true);
             }
         }
     }

     /**
      * A queue which handles the CLOSE request.
      *
      * TODO : Check that when closing a session, all the pending requests are
      * correctly sent.
      */
     private class CloseAwareWriteQueue implements WriteRequestQueue {

         private final WriteRequestQueue queue;

         /**
          * {@inheritDoc}
          */
         public CloseAwareWriteQueue(WriteRequestQueue queue) {
             this.queue = queue;
         }

         /**
          * {@inheritDoc}
          */
         public synchronized WriteRequest poll(IoSession session) {
             WriteRequest answer = queue.poll(session);

             if (answer == CLOSE_REQUEST) {
                 AbstractIoSession.this.close( true );
                 dispose(session);
                 answer = null;
             }

             return answer;
         }

         /**
          * {@inheritDoc}
          */
         public void offer(IoSession session, WriteRequest e) {
             queue.offer(session, e);
         }

         /**
          * {@inheritDoc}
          */
         public boolean isEmpty(IoSession session) {
             return queue.isEmpty(session);
         }

         /**
          * {@inheritDoc}
          */
         public void clear(IoSession session) {
             queue.clear(session);
         }

         /**
          * {@inheritDoc}
          */
         public void dispose(IoSession session) {
             queue.dispose(session);
         }

         /**
          * {@inheritDoc}
          */
         public int size() {
             return queue.size();
         }
     }
 }