1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, 13 * software distributed under the License is distributed on an 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 15 * KIND, either express or implied. See the License for the 16 * specific language governing permissions and limitations 17 * under the License. 18 * 19 */ 20 package org.apache.mina.codec; 21 22 import java.nio.ByteBuffer; 23 24 /** 25 * Decodes binary or protocol-specific data into higher-level message objects. 26 * 27 * Must be immutable, a CONTEXT will be provided per session. 28 * 29 * @param <INPUT> the incoming message to decode (the low level message, usually a {@link ByteBuffer}) 30 * @param <OUTPUT> the decoded message (your high level protocol Pojo/DTO) 31 * @param <DECODING_STATE> the context where to save the current decoding state (e.g. accumulated bytes, encoding 32 * context switching..) 33 * 34 * @author <a href="http://mina.apache.org">Apache MINA Project</a> 35 * 36 */ 37 public interface ProtocolDecoder<INPUT, OUTPUT, DECODING_STATE> { 38 39 /** 40 * Create a new session context for this decoder 41 * 42 * @return the newly created context 43 */ 44 DECODING_STATE createDecoderState(); 45 46 /** 47 * Decode binary or protocol-specific content of type <code>INPUT</code> into higher-level protocol message objects, 48 * of type OUTPUT 49 * 50 * @param input the received message to decode 51 * @param context the decoding context (will be stored in the session for the next decode call) 52 * @return the decoded message or <code>null</code> if nothing was decoded 53 */ 54 OUTPUT decode(INPUT input, DECODING_STATE context); 55 56 /** 57 * Finish decoding, for example if the decoder accumulated some unused input, it should discard it, or throw an 58 * Exception 59 */ 60 void finishDecode(DECODING_STATE context); 61 }