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;
018
019 import java.util.Map;
020 import java.util.Set;
021
022 import javax.activation.DataHandler;
023
024 /**
025 * Implements the <a
026 * href="http://camel.apache.org/message.html">Message</a> pattern and
027 * represents an inbound or outbound message as part of an {@link Exchange}.
028 * <p/>
029 * See {@link org.apache.camel.impl.DefaultMessage DefaultMessage} for how headers
030 * is represented in Camel using a {@link org.apache.camel.util.CaseInsensitiveMap CaseInsensitiveMap}.
031 *
032 * @version $Revision: 946635 $
033 */
034 public interface Message {
035
036 /**
037 * Returns the id of the message
038 *
039 * @return the message id
040 */
041 String getMessageId();
042
043 /**
044 * Sets the id of the message
045 *
046 * @param messageId id of the message
047 */
048 void setMessageId(String messageId);
049
050 /**
051 * Returns the exchange this message is related to
052 *
053 * @return the exchange
054 */
055 Exchange getExchange();
056
057 /**
058 * Returns true if this message represents a fault
059 *
060 * @return <tt>true</tt> if this is a fault message, <tt>false</tt> for regular messages.
061 */
062 boolean isFault();
063
064 /**
065 * Sets the fault flag on this message
066 *
067 * @param fault the fault flag
068 */
069 void setFault(boolean fault);
070
071 /**
072 * Accesses a specific header
073 *
074 * @param name name of header
075 * @return the value of the given header or <tt>null</tt> if there is no
076 * header for the given name
077 */
078 Object getHeader(String name);
079
080 /**
081 * Accesses a specific header
082 *
083 * @param name name of header
084 * @param defaultValue the default value to return if header was absent
085 * @return the value of the given header or <tt>defaultValue</tt> if there is no
086 * header for the given name
087 */
088 Object getHeader(String name, Object defaultValue);
089
090 /**
091 * Returns a header associated with this message by name and specifying the
092 * type required
093 *
094 * @param name the name of the header
095 * @param type the type of the header
096 * @return the value of the given header or <tt>null</tt> if there is no header for
097 * the given name or <tt>null</tt> if it cannot be converted to the given type
098 */
099 <T> T getHeader(String name, Class<T> type);
100
101 /**
102 * Returns a header associated with this message by name and specifying the
103 * type required
104 *
105 * @param name the name of the header
106 * @param defaultValue the default value to return if header was absent
107 * @param type the type of the header
108 * @return the value of the given header or <tt>defaultValue</tt> if there is no header for
109 * the given name or <tt>null</tt> if it cannot be converted to the given type
110 */
111 <T> T getHeader(String name, Object defaultValue, Class<T> type);
112
113 /**
114 * Sets a header on the message
115 *
116 * @param name of the header
117 * @param value to associate with the name
118 */
119 void setHeader(String name, Object value);
120
121 /**
122 * Removes the named header from this message
123 *
124 * @param name name of the header
125 * @return the old value of the header
126 */
127 Object removeHeader(String name);
128
129 /**
130 * Removes the headers from this message
131 *
132 * @param pattern pattern of names
133 * @return boolean whether any headers matched
134 */
135 boolean removeHeaders(String pattern);
136
137 /**
138 * Returns all of the headers associated with the message.
139 * <p/>
140 * See {@link org.apache.camel.impl.DefaultMessage DefaultMessage} for how headers
141 * is represented in Camel using a {@link org.apache.camel.util.CaseInsensitiveMap CaseInsensitiveMap}.
142 * <p/>
143 * <b>Important:</b> If you want to walk the returned {@link Map} and fetch all the keys and values, you should use
144 * the {@link java.util.Map#entrySet()} method, which ensure you get the keys in the original case.
145 *
146 * @return all the headers in a Map
147 */
148 Map<String, Object> getHeaders();
149
150 /**
151 * Set all the headers associated with this message
152 *
153 * @param headers headers to set
154 */
155 void setHeaders(Map<String, Object> headers);
156
157 /**
158 * Returns whether has any headers has been set.
159 *
160 * @return <tt>true</tt> if any headers has been set
161 */
162 boolean hasHeaders();
163
164 /**
165 * Returns the body of the message as a POJO
166 * <p/>
167 * The body can be <tt>null</tt> if no body is set
168 *
169 * @return the body, can be <tt>null</tt>
170 */
171 Object getBody();
172
173 /**
174 * Returns the body of the message as a POJO
175 *
176 * @return the body, is never <tt>null</tt>
177 * @throws InvalidPayloadException Is thrown if the body being <tt>null</tt> or wrong class type
178 */
179 Object getMandatoryBody() throws InvalidPayloadException;
180
181 /**
182 * Returns the body as the specified type
183 *
184 * @param type the type that the body
185 * @return the body of the message as the specified type, or <tt>null</tt> if not possible to convert
186 */
187 <T> T getBody(Class<T> type);
188
189 /**
190 * Returns the mandatory body as the specified type
191 *
192 * @param type the type that the body
193 * @return the body of the message as the specified type, is never <tt>null</tt>.
194 * @throws InvalidPayloadException Is thrown if the body being <tt>null</tt> or wrong class type
195 */
196 <T> T getMandatoryBody(Class<T> type) throws InvalidPayloadException;
197
198 /**
199 * Sets the body of the message
200 *
201 * @param body the body
202 */
203 void setBody(Object body);
204
205 /**
206 * Sets the body of the message as a specific type
207 *
208 * @param body the body
209 * @param type the type of the body
210 */
211 <T> void setBody(Object body, Class<T> type);
212
213 /**
214 * Creates a copy of this message so that it can be used and possibly
215 * modified further in another exchange
216 *
217 * @return a new message instance copied from this message
218 */
219 Message copy();
220
221 /**
222 * Copies the contents of the other message into this message
223 *
224 * @param message the other message
225 */
226 void copyFrom(Message message);
227
228 /**
229 * Returns the attachment specified by the id
230 *
231 * @param id the id under which the attachment is stored
232 * @return the data handler for this attachment or <tt>null</tt>
233 */
234 DataHandler getAttachment(String id);
235
236 /**
237 * Returns a set of attachment names of the message
238 *
239 * @return a set of attachment names
240 */
241 Set<String> getAttachmentNames();
242
243 /**
244 * Removes the attachment specified by the id
245 *
246 * @param id the id of the attachment to remove
247 */
248 void removeAttachment(String id);
249
250 /**
251 * Adds an attachment to the message using the id
252 *
253 * @param id the id to store the attachment under
254 * @param content the data handler for the attachment
255 */
256 void addAttachment(String id, DataHandler content);
257
258 /**
259 * Returns all attachments of the message
260 *
261 * @return the attachments in a map or <tt>null</tt>
262 */
263 Map<String, DataHandler> getAttachments();
264
265 /**
266 * Set all the attachments associated with this message
267 *
268 * @param attachments the attachments
269 */
270 void setAttachments(Map<String, DataHandler> attachments);
271
272 /**
273 * Returns whether this message has attachments.
274 *
275 * @return <tt>true</tt> if this message has any attachments.
276 */
277 boolean hasAttachments();
278
279 /**
280 * Returns the unique ID for a message exchange if this message is capable
281 * of creating one or <tt>null</tt> if not
282 *
283 * @return the created exchange id, or <tt>null</tt> if not capable of creating
284 */
285 String createExchangeId();
286 }