/*
 * 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.sctp;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandler;
import io.netty.channel.sctp.SctpMessage;
import io.netty.handler.codec.MessageToMessageDecoder;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

MessageToMessageDecoder which will take care of handle fragmented SctpMessages, so only complete SctpMessages will be forwarded to the next ChannelInboundHandler.
/** * {@link MessageToMessageDecoder} which will take care of handle fragmented {@link SctpMessage}s, so * only <strong>complete</strong> {@link SctpMessage}s will be forwarded to the next * {@link ChannelInboundHandler}. */
public class SctpMessageCompletionHandler extends MessageToMessageDecoder<SctpMessage> { private final Map<Integer, ByteBuf> fragments = new HashMap<Integer, ByteBuf>(); @Override protected void decode(ChannelHandlerContext ctx, SctpMessage msg, List<Object> out) throws Exception { final ByteBuf byteBuf = msg.content(); final int protocolIdentifier = msg.protocolIdentifier(); final int streamIdentifier = msg.streamIdentifier(); final boolean isComplete = msg.isComplete(); final boolean isUnordered = msg.isUnordered(); ByteBuf frag = fragments.remove(streamIdentifier); if (frag == null) { frag = Unpooled.EMPTY_BUFFER; } if (isComplete && !frag.isReadable()) { //data chunk is not fragmented out.add(msg); } else if (!isComplete && frag.isReadable()) { //more message to complete fragments.put(streamIdentifier, Unpooled.wrappedBuffer(frag, byteBuf)); } else if (isComplete && frag.isReadable()) { //last message to complete SctpMessage assembledMsg = new SctpMessage( protocolIdentifier, streamIdentifier, isUnordered, Unpooled.wrappedBuffer(frag, byteBuf)); out.add(assembledMsg); } else { //first incomplete message fragments.put(streamIdentifier, byteBuf); } byteBuf.retain(); } @Override public void handlerRemoved(ChannelHandlerContext ctx) throws Exception { for (ByteBuf buffer: fragments.values()) { buffer.release(); } fragments.clear(); super.handlerRemoved(ctx); } }