001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.mina.example.imagine.step1.codec; 021 022import org.apache.mina.filter.codec.ProtocolDecoderOutput; 023import org.apache.mina.filter.codec.CumulativeProtocolDecoder; 024import org.apache.mina.core.buffer.IoBuffer; 025import org.apache.mina.core.session.IoSession; 026import org.apache.mina.example.imagine.step1.ImageResponse; 027 028import javax.imageio.ImageIO; 029import java.awt.image.BufferedImage; 030import java.io.ByteArrayInputStream; 031import java.io.IOException; 032 033/** 034 * a decoder for {@link ImageResponse} objects 035 * 036 * @author <a href="http://mina.apache.org">Apache MINA Project</a> 037 */ 038 039public class ImageResponseDecoder extends CumulativeProtocolDecoder { 040 041 private static final String DECODER_STATE_KEY = ImageResponseDecoder.class.getName() + ".STATE"; 042 043 public static final int MAX_IMAGE_SIZE = 5 * 1024 * 1024; 044 045 private static class DecoderState { 046 private BufferedImage image1; 047 } 048 049 protected boolean doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception { 050 DecoderState decoderState = (DecoderState) session.getAttribute(DECODER_STATE_KEY); 051 if (decoderState == null) { 052 decoderState = new DecoderState(); 053 session.setAttribute(DECODER_STATE_KEY, decoderState); 054 } 055 if (decoderState.image1 == null) { 056 // try to read first image 057 if (in.prefixedDataAvailable(4, MAX_IMAGE_SIZE)) { 058 decoderState.image1 = readImage(in); 059 } else { 060 // not enough data available to read first image 061 return false; 062 } 063 } 064 if (decoderState.image1 != null) { 065 // try to read second image 066 if (in.prefixedDataAvailable(4, MAX_IMAGE_SIZE)) { 067 BufferedImage image2 = readImage(in); 068 ImageResponse imageResponse = new ImageResponse(decoderState.image1, image2); 069 out.write(imageResponse); 070 decoderState.image1 = null; 071 return true; 072 } else { 073 // not enough data available to read second image 074 return false; 075 } 076 } 077 return false; 078 } 079 080 private BufferedImage readImage(IoBuffer in) throws IOException { 081 int length = in.getInt(); 082 byte[] bytes = new byte[length]; 083 in.get(bytes); 084 ByteArrayInputStream bais = new ByteArrayInputStream(bytes); 085 return ImageIO.read(bais); 086 } 087 088}