SimpleChannelInboundHandler.java — netty Source File

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/*
 * Copyright 2013 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:
 *
 *   https://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 io.netty.channel;

import io.netty.util.ReferenceCountUtil;
import io.netty.util.internal.TypeParameterMatcher;

/**
 * {@link ChannelInboundHandlerAdapter} which allows to explicit only handle a specific type of messages.
 *
 * For example here is an implementation which only handle {@link String} messages.
 *
 * <pre>
 *     public class StringHandler extends
 *             {@link SimpleChannelInboundHandler}&lt;{@link String}&gt; {
 *
 *         {@code @Override}
 *         protected void channelRead0({@link ChannelHandlerContext} ctx, {@link String} message)
 *                 throws {@link Exception} {
 *             System.out.println(message);
 *         }
 *     }
 * </pre>
 *
 * Be aware that depending of the constructor parameters it will release all handled messages by passing them to
 * {@link ReferenceCountUtil#release(Object)}. In this case you may need to use
 * {@link ReferenceCountUtil#retain(Object)} if you pass the object to the next handler in the {@link ChannelPipeline}.
 */
public abstract class SimpleChannelInboundHandler<I> extends ChannelInboundHandlerAdapter {

    private final TypeParameterMatcher matcher;
    private final boolean autoRelease;

    /**
     * see {@link #SimpleChannelInboundHandler(boolean)} with {@code true} as boolean parameter.
     */
    protected SimpleChannelInboundHandler() {
        this(true);
    }

    /**
     * Create a new instance which will try to detect the types to match out of the type parameter of the class.
     *
     * @param autoRelease   {@code true} if handled messages should be released automatically by passing them to
     *                      {@link ReferenceCountUtil#release(Object)}.
     */
    protected SimpleChannelInboundHandler(boolean autoRelease) {
// ... (61 more lines)