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/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project 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.jboss.netty.channel;

import java.net.SocketAddress;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.logging.InternalLogger;
import org.jboss.netty.logging.InternalLoggerFactory;


/**
 * A {@link ChannelHandler} which provides an individual handler method
 * for each event type.  This handler down-casts the received upstream or
 * or downstream event into more meaningful sub-type event and calls an
 * appropriate handler method with the down-cast event.  For an upstream
 * event, the names of the methods are identical to the upstream event names,
 * as introduced in the {@link ChannelEvent} documentation.  For a
 * downstream event, the names of the methods starts with the name of the
 * operation and ends with {@code "Requested"}
 * (e.g. {@link #writeRequested(ChannelHandlerContext, MessageEvent) writeRequested}.)
 * 

* Please use {@link SimpleChannelUpstreamHandler} or * {@link SimpleChannelDownstreamHandler} if you want to intercept only * upstream or downstream events. * *

Overriding the {@link #handleUpstream(ChannelHandlerContext, ChannelEvent) handleUpstream} * and {@link #handleDownstream(ChannelHandlerContext, ChannelEvent) handleDownstream} method

*

* You can override the {@link #handleUpstream(ChannelHandlerContext, ChannelEvent) handleUpstream} * and {@link #handleDownstream(ChannelHandlerContext, ChannelEvent) handleDownstream} * method just like overriding an ordinary Java method. Please make sure to * call {@code super.handleUpstream()} or {@code super.handleDownstream()} so * that other handler methods are invoked properly: *

*
public class MyChannelHandler extends {@link SimpleChannelHandler} {
 *
 *     {@code @Override}
 *     public void handleUpstream({@link ChannelHandlerContext} ctx, {@link ChannelEvent} e) throws Exception {
 *
 *         // Log all channel state changes.
 *         if (e instanceof {@link ChannelStateEvent}) {
 *             logger.info("Channel state changed: " + e);
 *         }
 *
 *         super.handleUpstream(ctx, e);
 *     }
 *
 *     {@code @Override}
 *     public void handleDownstream({@link ChannelHandlerContext} ctx, {@link ChannelEvent} e) throws Exception {
 *
 *         // Log all channel state changes.
 *         if (e instanceof {@link MessageEvent}) {
 *             logger.info("Writing:: " + e);
 *         }
 *
 *         super.handleDownstream(ctx, e);
 *     }
 * }
*/ public class SimpleChannelHandler implements ChannelUpstreamHandler, ChannelDownstreamHandler { private static final InternalLogger logger = InternalLoggerFactory.getInstance(SimpleChannelHandler.class.getName()); /** * {@inheritDoc} Down-casts the received upstream event into more * meaningful sub-type event and calls an appropriate handler method with * the down-casted event. */ public void handleUpstream( ChannelHandlerContext ctx, ChannelEvent e) throws Exception { if (e instanceof MessageEvent) { messageReceived(ctx, (MessageEvent) e); } else if (e instanceof WriteCompletionEvent) { WriteCompletionEvent evt = (WriteCompletionEvent) e; writeComplete(ctx, evt); } else if (e instanceof ChildChannelStateEvent) { ChildChannelStateEvent evt = (ChildChannelStateEvent) e; if (evt.getChildChannel().isOpen()) { childChannelOpen(ctx, evt); } else { childChannelClosed(ctx, evt); } } else if (e instanceof ChannelStateEvent) { ChannelStateEvent evt = (ChannelStateEvent) e; switch (evt.getState()) { case OPEN: if (Boolean.TRUE.equals(evt.getValue())) { channelOpen(ctx, evt); } else { channelClosed(ctx, evt); } break; case BOUND: if (evt.getValue() != null) { channelBound(ctx, evt); } else { channelUnbound(ctx, evt); } break; case CONNECTED: if (evt.getValue() != null) { channelConnected(ctx, evt); } else { channelDisconnected(ctx, evt); } break; case INTEREST_OPS: channelInterestChanged(ctx, evt); break; default: ctx.sendUpstream(e); } } else if (e instanceof ExceptionEvent) { exceptionCaught(ctx, (ExceptionEvent) e); } else { ctx.sendUpstream(e); } } /** * Invoked when a message object (e.g: {@link ChannelBuffer}) was received * from a remote peer. */ public void messageReceived( ChannelHandlerContext ctx, MessageEvent e) throws Exception { ctx.sendUpstream(e); } /** * Invoked when an exception was raised by an I/O thread or a * {@link ChannelHandler}. */ public void exceptionCaught( ChannelHandlerContext ctx, ExceptionEvent e) throws Exception { if (this == ctx.getPipeline().getLast()) { logger.warn( "EXCEPTION, please implement " + getClass().getName() + ".exceptionCaught() for proper handling.", e.getCause()); } ctx.sendUpstream(e); } /** * Invoked when a {@link Channel} is open, but not bound nor connected. */ public void channelOpen( ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendUpstream(e); } /** * Invoked when a {@link Channel} is open and bound to a local address, * but not connected. */ public void channelBound( ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendUpstream(e); } /** * Invoked when a {@link Channel} is open, bound to a local address, and * connected to a remote address. */ public void channelConnected( ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendUpstream(e); } /** * Invoked when a {@link Channel}'s {@link Channel#getInterestOps() interestOps} * was changed. */ public void channelInterestChanged( ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendUpstream(e); } /** * Invoked when a {@link Channel} was disconnected from its remote peer. */ public void channelDisconnected( ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendUpstream(e); } /** * Invoked when a {@link Channel} was unbound from the current local address. */ public void channelUnbound( ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendUpstream(e); } /** * Invoked when a {@link Channel} was closed and all its related resources * were released. */ public void channelClosed( ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendUpstream(e); } /** * Invoked when something was written into a {@link Channel}. */ public void writeComplete( ChannelHandlerContext ctx, WriteCompletionEvent e) throws Exception { ctx.sendUpstream(e); } /** * Invoked when a child {@link Channel} was open. * (e.g. a server channel accepted a connection) */ public void childChannelOpen( ChannelHandlerContext ctx, ChildChannelStateEvent e) throws Exception { ctx.sendUpstream(e); } /** * Invoked when a child {@link Channel} was closed. * (e.g. the accepted connection was closed) */ public void childChannelClosed( ChannelHandlerContext ctx, ChildChannelStateEvent e) throws Exception { ctx.sendUpstream(e); } /** * {@inheritDoc} Down-casts the received downstream event into more * meaningful sub-type event and calls an appropriate handler method with * the down-casted event. */ public void handleDownstream(ChannelHandlerContext ctx, ChannelEvent e) throws Exception { if (e instanceof MessageEvent) { writeRequested(ctx, (MessageEvent) e); } else if (e instanceof ChannelStateEvent) { ChannelStateEvent evt = (ChannelStateEvent) e; switch (evt.getState()) { case OPEN: if (!Boolean.TRUE.equals(evt.getValue())) { closeRequested(ctx, evt); } break; case BOUND: if (evt.getValue() != null) { bindRequested(ctx, evt); } else { unbindRequested(ctx, evt); } break; case CONNECTED: if (evt.getValue() != null) { connectRequested(ctx, evt); } else { disconnectRequested(ctx, evt); } break; case INTEREST_OPS: setInterestOpsRequested(ctx, evt); break; default: ctx.sendDownstream(e); } } else { ctx.sendDownstream(e); } } /** * Invoked when {@link Channel#write(Object)} is called. */ public void writeRequested(ChannelHandlerContext ctx, MessageEvent e) throws Exception { ctx.sendDownstream(e); } /** * Invoked when {@link Channel#bind(SocketAddress)} was called. */ public void bindRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendDownstream(e); } /** * Invoked when {@link Channel#connect(SocketAddress)} was called. */ public void connectRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendDownstream(e); } /** * Invoked when {@link Channel#setInterestOps(int)} was called. */ public void setInterestOpsRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendDownstream(e); } /** * Invoked when {@link Channel#disconnect()} was called. */ public void disconnectRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendDownstream(e); } /** * Invoked when {@link Channel#unbind()} was called. */ public void unbindRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendDownstream(e); } /** * Invoked when {@link Channel#close()} was called. */ public void closeRequested(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { ctx.sendDownstream(e); } }




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