1 /*
2 * $Id: InboundHeaders.java 20321 2010-11-24 15:21:24Z dfeist $
3 * --------------------------------------------------------------------------------------
4 * Copyright (c) MuleSoft, Inc. All rights reserved. http://www.mulesoft.com
5 *
6 * The software in this package is published under the terms of the CPAL v1.0
7 * license, a copy of which has been included with this distribution in the
8 * LICENSE.txt file.
9 */
10
11 package org.mule.api.annotations.param;
12
13 import org.mule.api.annotations.meta.Evaluator;
14
15 import java.lang.annotation.Documented;
16 import java.lang.annotation.ElementType;
17 import java.lang.annotation.Retention;
18 import java.lang.annotation.RetentionPolicy;
19 import java.lang.annotation.Target;
20
21 /**
22 * Used on component methods, this annotation marks the method parameter that will be used to pass in one or more of the headers received.
23 * This annotation value can define a single header, a comma-separated list of header names, '*' to denote all headers, or a comma-separated list
24 * of wildcard expressions such as 'MULE_*, X-*'. By default, if a named header is not present on the current message, an exception will be thrown.
25 * However, if the header name is defined with the '?' post fix, it will be marked as optional.
26 * <p/>
27 * When defining multiple header names or using wildcards, the parameter can be a {@link java.util.Map} or {@link java.util.List}. If a
28 * {@link java.util.Map} is used, the header name and value is passed in. If {@link java.util.List} is used, just the header values are used.
29 * If a single header name is defined, the header type can be used as the parameter type, though {@link java.util.List} or {@link java.util.Map}
30 * can be used too.
31 *
32 * The Inbound headers collection is immutable, so the headers Map or List passed in will be immutable too. Attempting to write to the Map or List will result in an {@link UnsupportedOperationException}.
33 */
34 @Target(ElementType.PARAMETER)
35 @Retention(RetentionPolicy.RUNTIME)
36 @Documented
37 @Evaluator("messageProperty")
38 public @interface InboundHeaders
39 {
40 /**
41 * Defines the headers that should be injected into the parameter. This can be a single header, a comma-separated
42 * list of header names,'*' to denote all headers or a comma-separated list of wildcard expressions. By default,
43 * if a named header is not present, an exception will be thrown. However, if the header name is defined with the
44 * '?' post fix, it will be marked as optional.
45 * The optional '?' post fix is not supported when using wildcard expressions
46 *
47 * @return the header expression used to query the message for headers
48 */
49 String value();
50 }