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.util;
018
019 import java.util.HashMap;
020 import java.util.Map;
021
022 import org.apache.camel.Endpoint;
023 import org.apache.camel.Exchange;
024 import org.apache.camel.ExchangePattern;
025 import org.apache.camel.InvalidPayloadException;
026 import org.apache.camel.InvalidTypeException;
027 import org.apache.camel.Message;
028 import org.apache.camel.NoSuchBeanException;
029 import org.apache.camel.NoSuchEndpointException;
030 import org.apache.camel.NoSuchHeaderException;
031 import org.apache.camel.NoSuchPropertyException;
032 import org.apache.camel.NoTypeConversionAvailableException;
033
034 /**
035 * Some helper methods for working with {@link Exchange} objects
036 *
037 * @version $Revision: 52365 $
038 */
039 public final class ExchangeHelper {
040
041 /**
042 * Utility classes should not have a public constructor.
043 */
044 private ExchangeHelper() {
045 }
046
047 /**
048 * Extracts the exchange property of the given name and type; if it is not present then the
049 * default value will be used
050 *
051 * @param exchange the message exchange
052 * @param propertyName the name of the property on the exchange
053 * @param type the expected type of the property
054 * @param defaultValue the default value to be used if the property name does not exist or could not be
055 * converted to the given type
056 * @return the property value as the given type or the defaultValue if it could not be found or converted
057 */
058 public static <T> T getExchangeProperty(Exchange exchange, String propertyName, Class<T> type, T defaultValue) {
059 T answer = exchange.getProperty(propertyName, type);
060 if (answer == null) {
061 return defaultValue;
062 }
063 return answer;
064 }
065
066
067 /**
068 * Attempts to resolve the endpoint for the given value
069 *
070 * @param exchange the message exchange being processed
071 * @param value the value which can be an {@link Endpoint} or an object
072 * which provides a String representation of an endpoint via
073 * {@link #toString()}
074 *
075 * @return the endpoint
076 * @throws NoSuchEndpointException if the endpoint cannot be resolved
077 */
078 @SuppressWarnings({"unchecked" })
079 public static <E extends Exchange> Endpoint<E> resolveEndpoint(E exchange, Object value)
080 throws NoSuchEndpointException {
081 Endpoint<E> endpoint;
082 if (value instanceof Endpoint) {
083 endpoint = (Endpoint<E>)value;
084 } else {
085 String uri = value.toString();
086 endpoint = CamelContextHelper.getMandatoryEndpoint(exchange.getContext(), uri);
087 }
088 return endpoint;
089 }
090
091 public static <T> T getMandatoryProperty(Exchange exchange, String propertyName, Class<T> type)
092 throws NoSuchPropertyException {
093 try {
094 T result = exchange.getProperty(propertyName, type);
095 if (result != null) {
096 return result;
097 }
098 } catch (NoTypeConversionAvailableException ex) {
099 // will throw NoSuchPropertyException below
100 }
101 throw new NoSuchPropertyException(exchange, propertyName, type);
102 }
103
104 public static <T> T getMandatoryHeader(Exchange exchange, String propertyName, Class<T> type)
105 throws NoSuchHeaderException {
106 T answer = exchange.getIn().getHeader(propertyName, type);
107 if (answer == null) {
108 throw new NoSuchHeaderException(exchange, propertyName, type);
109 }
110 return answer;
111 }
112
113 /**
114 * Returns the mandatory inbound message body of the correct type or throws
115 * an exception if it is not present
116 */
117 public static Object getMandatoryInBody(Exchange exchange) throws InvalidPayloadException {
118 Object answer = exchange.getIn().getBody();
119 if (answer == null) {
120 throw new InvalidPayloadException(exchange, Object.class);
121 }
122 return answer;
123 }
124
125 /**
126 * Returns the mandatory inbound message body of the correct type or throws
127 * an exception if it is not present
128 */
129 public static <T> T getMandatoryInBody(Exchange exchange, Class<T> type) throws InvalidPayloadException {
130 T answer = exchange.getIn().getBody(type);
131 if (answer == null) {
132 throw new InvalidPayloadException(exchange, type);
133 }
134 return answer;
135 }
136
137 /**
138 * Returns the mandatory outbound message body of the correct type or throws
139 * an exception if it is not present
140 */
141 public static Object getMandatoryOutBody(Exchange exchange) throws InvalidPayloadException {
142 Message out = exchange.getOut();
143 Object answer = out.getBody();
144 if (answer == null) {
145 throw new InvalidPayloadException(exchange, Object.class, out);
146 }
147 return answer;
148 }
149
150 /**
151 * Returns the mandatory outbound message body of the correct type or throws
152 * an exception if it is not present
153 */
154 public static <T> T getMandatoryOutBody(Exchange exchange, Class<T> type) throws InvalidPayloadException {
155 Message out = exchange.getOut();
156 T answer = out.getBody(type);
157 if (answer == null) {
158 throw new InvalidPayloadException(exchange, type, out);
159 }
160 return answer;
161 }
162
163 /**
164 * Converts the value to the given expected type or throws an exception
165 */
166 public static <T> T convertToMandatoryType(Exchange exchange, Class<T> type, Object value)
167 throws InvalidTypeException {
168 T answer = convertToType(exchange, type, value);
169 if (answer == null) {
170 throw new InvalidTypeException(exchange, value, type);
171 }
172 return answer;
173 }
174
175 /**
176 * Converts the value to the given expected type returning null if it could
177 * not be converted
178 */
179 public static <T> T convertToType(Exchange exchange, Class<T> type, Object value) {
180 return exchange.getContext().getTypeConverter().convertTo(type, exchange, value);
181 }
182
183 /**
184 * Copies the results of a message exchange from the source exchange to the result exchange
185 * which will copy the out and fault message contents and the exception
186 *
187 * @param result the result exchange which will have the output and error state added
188 * @param source the source exchange which is not modified
189 */
190 public static void copyResults(Exchange result, Exchange source) {
191 if (result != source) {
192 result.setException(source.getException());
193 Message fault = source.getFault(false);
194 if (fault != null) {
195 result.getFault(true).copyFrom(fault);
196 }
197
198 Message out = source.getOut(false);
199 if (out != null) {
200 result.getOut(true).copyFrom(out);
201 } else {
202 // no results so lets copy the last input
203 // as the final processor on a pipeline might not
204 // have created any OUT; such as a mock:endpoint
205 // so lets assume the last IN is the OUT
206 result.getOut(true).copyFrom(source.getIn());
207 }
208 result.getProperties().clear();
209 result.getProperties().putAll(source.getProperties());
210 }
211 }
212
213 /**
214 * Returns true if the given exchange pattern (if defined) can support IN messagea
215 *
216 * @param exchange the exchange to interrogate
217 * @return true if the exchange is defined as an {@link ExchangePattern} which supports
218 * IN messages
219 */
220 public static boolean isInCapable(Exchange exchange) {
221 ExchangePattern pattern = exchange.getPattern();
222 return pattern != null && pattern.isInCapable();
223 }
224
225 /**
226 * Returns true if the given exchange pattern (if defined) can support OUT messagea
227 *
228 * @param exchange the exchange to interrogate
229 * @return true if the exchange is defined as an {@link ExchangePattern} which supports
230 * OUT messages
231 */
232 public static boolean isOutCapable(Exchange exchange) {
233 ExchangePattern pattern = exchange.getPattern();
234 return pattern != null && pattern.isOutCapable();
235 }
236
237 /**
238 * Creates a new instance of the given type from the injector
239 */
240 public static <T> T newInstance(Exchange exchange, Class<T> type) {
241 return exchange.getContext().getInjector().newInstance(type);
242 }
243
244 /**
245 * Creates a Map of the variables which are made available to a script or template
246 *
247 * @param exchange the exchange to make available
248 * @return a Map populated with the require dvariables
249 */
250 public static Map createVariableMap(Exchange exchange) {
251 Map answer = new HashMap();
252 populateVariableMap(exchange, answer);
253 return answer;
254 }
255
256 /**
257 * Populates the Map with the variables which are made available to a script or template
258 *
259 * @param exchange the exchange to make available
260 * @param map the map to populate
261 */
262 public static void populateVariableMap(Exchange exchange, Map map) {
263 map.put("exchange", exchange);
264 Message in = exchange.getIn();
265 map.put("in", in);
266 map.put("request", in);
267 map.put("headers", in.getHeaders());
268 map.put("body", in.getBody());
269 if (isOutCapable(exchange)) {
270 Message out = exchange.getOut(true);
271 map.put("out", out);
272 map.put("response", out);
273 }
274 map.put("camelContext", exchange.getContext());
275 }
276
277 /**
278 * Returns the MIME content type on the input message or null if one is not defined
279 */
280 public static String getContentType(Exchange exchange) {
281 return exchange.getIn().getHeader("Content-Type", String.class);
282 }
283
284 /**
285 * Performs a lookup in the registry of the mandatory bean name and throws an exception if it could not be found
286 */
287 public static Object lookupMandatoryBean(Exchange exchange, String name) {
288 Object value = lookupBean(exchange, name);
289 if (value == null) {
290 throw new NoSuchBeanException(name);
291 }
292 return value;
293 }
294
295 /**
296 * Performs a lookup in the registry of the mandatory bean name and throws an exception if it could not be found
297 */
298 public static <T> T lookupMandatoryBean(Exchange exchange, String name, Class<T> type) {
299 T value = lookupBean(exchange, name, type);
300 if (value == null) {
301 throw new NoSuchBeanException(name);
302 }
303 return value;
304 }
305
306 /**
307 * Performs a lookup in the registry of the bean name
308 */
309 public static Object lookupBean(Exchange exchange, String name) {
310 return exchange.getContext().getRegistry().lookup(name);
311 }
312
313 /**
314 * Performs a lookup in the registry of the bean name and type
315 */
316 public static <T> T lookupBean(Exchange exchange, String name, Class<T> type) {
317 return exchange.getContext().getRegistry().lookup(name, type);
318 }
319 }