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.CamelContext; 020 import org.apache.camel.Exchange; 021 import org.apache.camel.Message; 022 import org.apache.camel.NoTypeConversionAvailableException; 023 import org.apache.camel.TypeConverter; 024 import org.apache.camel.util.UuidGenerator; 025 026 /** 027 * A base class for implementation inheritence providing the core 028 * {@link Message} body handling features but letting the derived class deal 029 * with headers. 030 * 031 * Unless a specific provider wishes to do something particularly clever with 032 * headers you probably want to just derive from {@link DefaultMessage} 033 * 034 * @version $Revision: 52200 $ 035 */ 036 public abstract class MessageSupport implements Message { 037 private static final UuidGenerator DEFALT_ID_GENERATOR = new UuidGenerator(); 038 private Exchange exchange; 039 private Object body; 040 private String messageId; 041 042 public Object getBody() { 043 if (body == null) { 044 body = createBody(); 045 } 046 return body; 047 } 048 049 @SuppressWarnings({"unchecked" }) 050 public <T> T getBody(Class<T> type) { 051 return getBody(type, getBody()); 052 } 053 054 protected <T> T getBody(Class<T> type, Object body) { 055 Exchange e = getExchange(); 056 if (e != null) { 057 CamelContext camelContext = e.getContext(); 058 if (camelContext != null) { 059 TypeConverter converter = camelContext.getTypeConverter(); 060 try { 061 // lets first try converting the message itself first 062 // as for some types like InputStream v Reader its more efficient to do the transformation 063 // from the Message itself as its got efficient implementations of them, before trying the 064 // payload 065 return converter.convertTo(type, e, body); 066 } catch (NoTypeConversionAvailableException ex) { 067 // ignore 068 } 069 return converter.convertTo(type, this); 070 } 071 } 072 return (T)getBody(); 073 } 074 075 public void setBody(Object body) { 076 this.body = body; 077 } 078 079 public <T> void setBody(Object value, Class<T> type) { 080 Exchange e = getExchange(); 081 if (e != null) { 082 T v = e.getContext().getTypeConverter().convertTo(type, e, value); 083 if (v != null) { 084 value = v; 085 } 086 } 087 setBody(value); 088 } 089 090 public Message copy() { 091 Message answer = newInstance(); 092 answer.copyFrom(this); 093 return answer; 094 } 095 096 public void copyFrom(Message that) { 097 setMessageId(that.getMessageId()); 098 setBody(that.getBody()); 099 getHeaders().putAll(that.getHeaders()); 100 getAttachments().putAll(that.getAttachments()); 101 } 102 103 public Exchange getExchange() { 104 return exchange; 105 } 106 107 public void setExchange(Exchange exchange) { 108 this.exchange = exchange; 109 } 110 111 /** 112 * Returns a new instance 113 */ 114 public abstract Message newInstance(); 115 116 /** 117 * A factory method to allow a provider to lazily create the message body 118 * for inbound messages from other sources 119 * 120 * @return the value of the message body or null if there is no value 121 * available 122 */ 123 protected Object createBody() { 124 return null; 125 } 126 127 public String getMessageId() { 128 if (messageId == null) { 129 messageId = createMessageId(); 130 } 131 return this.messageId; 132 } 133 134 public void setMessageId(String messageId) { 135 this.messageId = messageId; 136 } 137 138 /** 139 * Lets allow implementations to auto-create a messageId 140 */ 141 protected String createMessageId() { 142 return DEFALT_ID_GENERATOR.generateId(); 143 } 144 }