Java tutorial
/* * 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 io.netty.handler.codec.spdy; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.MessageToMessageCodec; import io.netty.handler.codec.http.HttpMessage; import io.netty.handler.codec.spdy.SpdyHttpHeaders.Names; import io.netty.util.ReferenceCountUtil; import java.util.ArrayDeque; import java.util.List; import java.util.Queue; /** * {@link MessageToMessageCodec} that takes care of adding the right {@link SpdyHttpHeaders.Names#STREAM_ID} to the * {@link HttpMessage} if one is not present. This makes it possible to just re-use plan handlers current used * for HTTP. */ public class SpdyHttpResponseStreamIdHandler extends MessageToMessageCodec<Object, HttpMessage> { private static final Integer NO_ID = -1; private final Queue<Integer> ids = new ArrayDeque<Integer>(); @Override public boolean acceptInboundMessage(Object msg) throws Exception { return msg instanceof HttpMessage || msg instanceof SpdyRstStreamFrame; } @Override protected void encode(ChannelHandlerContext ctx, HttpMessage msg, List<Object> out) throws Exception { Integer id = ids.poll(); if (id != null && id.intValue() != NO_ID && !msg.headers().contains(SpdyHttpHeaders.Names.STREAM_ID)) { msg.headers().setInt(Names.STREAM_ID, id); } out.add(ReferenceCountUtil.retain(msg)); } @Override protected void decode(ChannelHandlerContext ctx, Object msg, List<Object> out) throws Exception { if (msg instanceof HttpMessage) { boolean contains = ((HttpMessage) msg).headers().contains(SpdyHttpHeaders.Names.STREAM_ID); if (!contains) { ids.add(NO_ID); } else { ids.add(((HttpMessage) msg).headers().getInt(Names.STREAM_ID)); } } else if (msg instanceof SpdyRstStreamFrame) { ids.remove(((SpdyRstStreamFrame) msg).streamId()); } out.add(ReferenceCountUtil.retain(msg)); } }