001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.camel.impl; 018 019 import org.apache.camel.Exchange; 020 import org.apache.camel.Message; 021 import org.apache.camel.TypeConverter; 022 import org.apache.camel.util.UuidGenerator; 023 024 /** 025 * A base class for implementation inheritence providing the core 026 * {@link Message} body handling features but letting the derived class deal 027 * with headers. 028 * 029 * Unless a specific provider wishes to do something particularly clever with 030 * headers you probably want to just derive from {@link DefaultMessage} 031 * 032 * @version $Revision: 37863 $ 033 */ 034 public abstract class MessageSupport implements Message { 035 private static final UuidGenerator DEFALT_ID_GENERATOR = new UuidGenerator(); 036 private Exchange exchange; 037 private Object body; 038 private String messageId; 039 040 public Object getBody() { 041 if (body == null) { 042 body = createBody(); 043 } 044 return body; 045 } 046 047 @SuppressWarnings({"unchecked" }) 048 public <T> T getBody(Class<T> type) { 049 Exchange e = getExchange(); 050 if (e != null) { 051 TypeConverter converter = e.getContext().getTypeConverter(); 052 T answer = converter.convertTo(type, getBody()); 053 if (answer == null) { 054 // lets first try converting the message itself first 055 // as for some types like InputStream v Reader its more efficient to do the transformation 056 // from the Message itself as its got efficient implementations of them, before trying the 057 // payload 058 answer = converter.convertTo(type, this); 059 } 060 return answer; 061 } 062 return (T)getBody(); 063 } 064 065 public void setBody(Object body) { 066 this.body = body; 067 } 068 069 public <T> void setBody(Object value, Class<T> type) { 070 Exchange e = getExchange(); 071 if (e != null) { 072 T v = e.getContext().getTypeConverter().convertTo(type, value); 073 if (v != null) { 074 value = v; 075 } 076 } 077 setBody(value); 078 } 079 080 public Message copy() { 081 Message answer = newInstance(); 082 answer.copyFrom(this); 083 return answer; 084 } 085 086 public void copyFrom(Message that) { 087 setMessageId(that.getMessageId()); 088 setBody(that.getBody()); 089 getHeaders().putAll(that.getHeaders()); 090 getAttachments().putAll(that.getAttachments()); 091 } 092 093 public Exchange getExchange() { 094 return exchange; 095 } 096 097 public void setExchange(Exchange exchange) { 098 this.exchange = exchange; 099 } 100 101 /** 102 * Returns a new instance 103 */ 104 public abstract Message newInstance(); 105 106 /** 107 * A factory method to allow a provider to lazily create the message body 108 * for inbound messages from other sources 109 * 110 * @return the value of the message body or null if there is no value 111 * available 112 */ 113 protected Object createBody() { 114 return null; 115 } 116 117 /** 118 * @return the messageId 119 */ 120 public String getMessageId() { 121 if (messageId == null) { 122 messageId = createMessageId(); 123 } 124 return this.messageId; 125 } 126 127 /** 128 * @param messageId the messageId to set 129 */ 130 public void setMessageId(String messageId) { 131 this.messageId = messageId; 132 } 133 134 /** 135 * Lets allow implementations to auto-create a messageId 136 */ 137 protected String createMessageId() { 138 return DEFALT_ID_GENERATOR.generateId(); 139 } 140 }