datagramfilterchain.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.support;

import java.util.Queue;

import org.apache.mina.common.ByteBuffer;
import org.apache.mina.common.IoFilter.WriteRequest;
import org.apache.mina.common.IoFilterChain;
import org.apache.mina.common.IoSession;
import org.apache.mina.common.support.AbstractIoFilterChain;

/**
 * An {@link IoFilterChain} for datagram transport (UDP/IP).
 *
 * @author The Apache Directory Project ([e-mail])
 */
class DatagramFilterChain extends AbstractIoFilterChain {

    DatagramFilterChain(IoSession parent) {
        super(parent);
    }

    @Override
    protected void doWrite(IoSession session, WriteRequest writeRequest) {
        DatagramSessionImpl s = (DatagramSessionImpl) session;
        Queue<WriteRequest> writeRequestQueue = s.getWriteRequestQueue();

        // SocketIoProcessor.doFlush() will reset it after write is finished
        // because the buffer will be passed with messageSent event.
        ((ByteBuffer) writeRequest.getMessage()).mark();
        synchronized (writeRequestQueue) {
            writeRequestQueue.add(writeRequest);
            if (writeRequestQueue.size() == 1
                    && session.getTrafficMask().isWritable()) {
                // Notify DatagramService only when writeRequestQueue was empty.
                s.getManagerDelegate().flushSession(s);
            }
        }
    }

    @Override
    protected void doClose(IoSession session) {
        DatagramSessionImpl s = (DatagramSessionImpl) session;
        DatagramService manager = s.getManagerDelegate();
        if (manager instanceof DatagramConnectorDelegate) {
            manager.closeSession(s);
        } else {
            ((DatagramAcceptorDelegate) manager).getListeners()
                    .fireSessionDestroyed(session);
            session.getCloseFuture().setClosed();
        }
    }
}