socketioprocessor.java

apache 的一个socket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.transport.socket.nio;

import java.io.IOException;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.Executor;

import org.apache.mina.common.ByteBuffer;
import org.apache.mina.common.ExceptionMonitor;
import org.apache.mina.common.IdleStatus;
import org.apache.mina.common.IoFilter.WriteRequest;
import org.apache.mina.common.WriteTimeoutException;
import org.apache.mina.util.NamePreservingRunnable;

/**
 * Performs all I/O operations for sockets which is connected or bound. This class is used by MINA internally.
 *
 * @author The Apache Directory Project ([e-mail])
 * @version $Rev: 556539 $, $Date: 2007-07-16 16:48:36 +0900 (월, 16  7월 2007) $,
 */
class SocketIoProcessor {
    private final Object lock = new Object();

    private final String threadName;

    private final Executor executor;

    private Selector selector;

    private final Queue<SocketSessionImpl> newSessions = new ConcurrentLinkedQueue<SocketSessionImpl>();

    private final Queue<SocketSessionImpl> removingSessions = new ConcurrentLinkedQueue<SocketSessionImpl>();

    private final Queue<SocketSessionImpl> flushingSessions = new ConcurrentLinkedQueue<SocketSessionImpl>();

    private final Queue<SocketSessionImpl> trafficControllingSessions = new ConcurrentLinkedQueue<SocketSessionImpl>();

    private Worker worker;

    private long lastIdleCheckTime = System.currentTimeMillis();

    SocketIoProcessor(String threadName, Executor executor) {
        this.threadName = threadName;
        this.executor = executor;
    }

    void addNew(SocketSessionImpl session) throws IOException {
        newSessions.add(session);
        startupWorker();
    }

    void remove(SocketSessionImpl session) throws IOException {
        scheduleRemove(session);
        startupWorker();
    }

    private void startupWorker() throws IOException {
        synchronized (lock) {
            if (worker == null) {
                selector = Selector.open();
                worker = new Worker();
                executor.execute(new NamePreservingRunnable(worker));
            }
            selector.wakeup();
        }
    }

    void flush(SocketSessionImpl session) {
        scheduleFlush(session);
        Selector selector = this.selector;
        if (selector != null) {
            selector.wakeup();
        }
    }

    void updateTrafficMask(SocketSessionImpl session) {
        scheduleTrafficControl(session);
        Selector selector = this.selector;
        if (selector != null) {
            selector.wakeup();
        }
    }

    private void scheduleRemove(SocketSessionImpl session) {
        removingSessions.add(session);
    }

    private void scheduleFlush(SocketSessionImpl session) {
        flushingSessions.add(session);
    }

    private void scheduleTrafficControl(SocketSessionImpl session) {
        trafficControllingSessions.add(session);
    }

    private void doAddNew() {
        for (;;) {
            SocketSessionImpl session = newSessions.poll();

            if (session == null)
                break;

            SocketChannel ch = session.getChannel();
            try {
                ch.configureBlocking(false);
                session.setSelectionKey(ch.register(selector,
                        SelectionKey.OP_READ, session));

                // AbstractIoFilterChain.CONNECT_FUTURE is cleared inside here
                // in AbstractIoFilterChain.fireSessionOpened().
                session.getServiceListeners().fireSessionCreated(session);
            } catch (IOException e) {
                // Clear the AbstractIoFilterChain.CONNECT_FUTURE attribute
                // and call ConnectFuture.setException().
                session.getFilterChain().fireExceptionCaught(session, e);
            }
        }
    }

    private void doRemove() {
        for (;;) {
            SocketSessionImpl session = removingSessions.poll();

            if (session == null)
                break;

            SocketChannel ch = session.getChannel();
            SelectionKey key = session.getSelectionKey();
            // Retry later if session is not yet fully initialized.
            // (In case that Session.close() is called before addSession() is processed)
            if (key == null) {
                scheduleRemove(session);
                break;
            }
            // skip if channel is already closed
            if (!key.isValid()) {
                continue;
            }

            try {
                key.cancel();
                ch.close();
            } catch (IOException e) {
                session.getFilterChain().fireExceptionCaught(session, e);
            } finally {
                releaseWriteBuffers(session);
                session.getServiceListeners().fireSessionDestroyed(session);
            }
        }
    }

    private void process(Set<SelectionKey> selectedKeys) {
        for (SelectionKey key : selectedKeys) {
            SocketSessionImpl session = (SocketSessionImpl) key.attachment();

            if (key.isReadable() && session.getTrafficMask().isReadable()) {
                read(session);
            }

            if (key.isWritable() && session.getTrafficMask().isWritable()) {
                scheduleFlush(session);
            }
        }

        selectedKeys.clear();
    }

    private void read(SocketSessionImpl session) {
        ByteBuffer buf = ByteBuffer.allocate(session.getReadBufferSize());
        SocketChannel ch = session.getChannel();

        try {
            int readBytes = 0;
            int ret;

            try {
                while ((ret = ch.read(buf.buf())) > 0) {
                    readBytes += ret;
                }
            } finally {
                buf.flip();
            }

            session.increaseReadBytes(readBytes);

            if (readBytes > 0) {
                session.getFilterChain().fireMessageReceived(session, buf);
                buf = null;
                
                if (readBytes * 2 < session.getReadBufferSize()) {
                    if (session.getReadBufferSize() > 64) {
                        session.setReadBufferSize(session.getReadBufferSize() >>> 1);
                    }
                } else if (readBytes == session.getReadBufferSize()) {
                    session.setReadBufferSize(session.getReadBufferSize() << 1);
                }
            }
            if (ret < 0) {
                scheduleRemove(session);
            }
        } catch (Throwable e) {
            if (e instanceof IOException)
                scheduleRemove(session);
            session.getFilterChain().fireExceptionCaught(session, e);
        } finally {
            if (buf != null)
                buf.release();
        }
    }

    private void notifyIdleness() {