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   /*
    * Copyright 2014 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.handler.codec.stomp;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.channel.ChannelHandler;
  import io.netty.channel.ChannelPipeline;
  import io.netty.handler.codec.MessageAggregator;
  import io.netty.handler.codec.TooLongFrameException;
  
  /**
   * A {@link ChannelHandler} that aggregates an {@link StompHeadersSubframe}
   * and its following {@link StompContentSubframe}s into a single {@link StompFrame}.
   * It is useful when you don't want to take care of STOMP frames whose content is 'chunked'.  Insert this
   * handler after {@link StompSubframeDecoder} in the {@link ChannelPipeline}:
   */
  public class StompSubframeAggregator
          extends MessageAggregator<StompSubframe, StompHeadersSubframe, StompContentSubframe, StompFrame> {
  
      /**
       * Creates a new instance.
       *
       * @param maxContentLength
       *        the maximum length of the aggregated content.
       *        If the length of the aggregated content exceeds this value,
       *        a {@link TooLongFrameException} will be raised.
       */
      public StompSubframeAggregator(int maxContentLength) {
          super(maxContentLength);
      }
  
      @Override
      protected boolean isStartMessage(StompSubframe msg) throws Exception {
          return msg instanceof StompHeadersSubframe;
      }
  
      @Override
      protected boolean isContentMessage(StompSubframe msg) throws Exception {
          return msg instanceof StompContentSubframe;
      }
  
      @Override
      protected boolean isLastContentMessage(StompContentSubframe msg) throws Exception {
          return msg instanceof LastStompContentSubframe;
      }
  
      @Override
      protected boolean isAggregated(StompSubframe msg) throws Exception {
          return msg instanceof StompFrame;
      }
  
      @Override
      protected boolean isContentLengthInvalid(StompHeadersSubframe start, int maxContentLength) {
          return (int) Math.min(Integer.MAX_VALUE, start.headers().getLong(StompHeaders.CONTENT_LENGTH, -1)) >
                       maxContentLength;
      }
  
      @Override
      protected Object newContinueResponse(StompHeadersSubframe start, int maxContentLength, ChannelPipeline pipeline) {
          return null;
      }
  
      @Override
      protected boolean closeAfterContinueResponse(Object msg) throws Exception {
          throw new UnsupportedOperationException();
      }
  
      @Override
      protected boolean ignoreContentAfterContinueResponse(Object msg) throws Exception {
          throw new UnsupportedOperationException();
      }
  
      @Override
      protected StompFrame beginAggregation(StompHeadersSubframe start, ByteBuf content) throws Exception {
          StompFrame ret = new DefaultStompFrame(start.command(), content);
          ret.headers().set(start.headers());
          return ret;
      }
  }