com.mnt.base.stream.netty.NConnectionHandler.java Source code

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Here is the source code for com.mnt.base.stream.netty.NConnectionHandler.java

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/**
 * $Revision: 1.0
 * $Date: 2013-5-21
 *
 * Copyright (C) 2013-2020 MNT. All rights reserved.
 *
 * Licensed 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 com.mnt.base.stream.netty;

import java.io.IOException;
import java.util.UUID;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.mnt.base.stream.comm.RequestHandler;

import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.Attribute;
import io.netty.util.AttributeKey;

/**
 * A ConnectionHandler is responsible for creating new sessions, destroying sessions and delivering
 * received stream package.
 *
 * @author Peng Peng
 */
@Sharable
public abstract class NConnectionHandler extends ChannelInboundHandlerAdapter {

    private static final Log Log = LogFactory.getLog(NConnectionHandler.class);

    public static final AttributeKey<RequestHandler> NSTREAM_HANDLER_KEY = AttributeKey
            .newInstance("NSTREAM-HANDLER");
    public static final AttributeKey<Connection> NSTREAM_CONNECTION_KEY = AttributeKey
            .newInstance("NSTREAM-CONNECTION");

    protected NConnectionHandler() {
        // empty
    }

    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        super.handlerAdded(ctx);

        Connection connection = createConnection(ctx, UUID.randomUUID().toString());
        // Create a new NIOConnection for the new session
        Attribute<Connection> connAttr = ctx.channel().attr(NSTREAM_CONNECTION_KEY);
        connAttr.set(connection);

        Attribute<RequestHandler> handlerAttr = ctx.channel().attr(NSTREAM_HANDLER_KEY);
        handlerAttr.set(createRequestHandler(connection));
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object message) throws Exception {

        RequestHandler handler = ctx.channel().attr(NSTREAM_HANDLER_KEY).get();

        try {
            handler.process((byte[]) message, null);
        } catch (Exception e) {
            Log.error("Closing connection due to error while processing message: " + message, e);
            Connection connection = (Connection) ctx.channel().attr(NSTREAM_CONNECTION_KEY).get();
            connection.close();
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        if (cause instanceof IOException) {
            Log.debug("ConnectionHandler: ", cause);
        } else {
            Log.error(cause.getMessage(), cause);
        }
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        Attribute<Connection> connAttr = ctx.channel().attr(NSTREAM_CONNECTION_KEY);
        Connection conn = connAttr.get();
        if (conn != null) {
            conn.close();
        }
        super.channelInactive(ctx);
    }

    public abstract Connection createConnection(ChannelHandlerContext channelHandlerContext, String connectionId);

    public abstract RequestHandler createRequestHandler(Connection connection);
}