Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
Transformer |
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| 0.0;0 |
1 | /* | |
2 | * Copyright (c) MuleSoft, Inc. All rights reserved. http://www.mulesoft.com | |
3 | * The software in this package is published under the terms of the CPAL v1.0 | |
4 | * license, a copy of which has been included with this distribution in the | |
5 | * LICENSE.txt file. | |
6 | */ | |
7 | package org.mule.api.annotations; | |
8 | ||
9 | import java.lang.annotation.Documented; | |
10 | import java.lang.annotation.ElementType; | |
11 | import java.lang.annotation.Retention; | |
12 | import java.lang.annotation.RetentionPolicy; | |
13 | import java.lang.annotation.Target; | |
14 | ||
15 | /** | |
16 | * Used to mark a that a class contains methods which are Mule Transformer, which means it will be made available in the Mule container. | |
17 | * Transformers are used to convert one object type to another. Mule uses them to provide automatic conversion of Java types | |
18 | * and now support Mime type conversion too. | |
19 | * | |
20 | * The parameters passed into the method define the source object(s) to transform, the return type of the method defines the return object type. | |
21 | * Transformers can define additional source types, that when received will be automatically converted to the parameter type accepted by | |
22 | * the annotated method. | |
23 | * | |
24 | * There are some rules to follow when writing a transformer method - | |
25 | * <ol> | |
26 | * <li>The method's declaring class must be annotated with ContainsTransformerMethods</li> | |
27 | * <li>The annotation must appear on a concrete method, not on an abstract or interface method</li> | |
28 | * <li>The method must be public</li> | |
29 | * <li>The method must have a non-void return type</li> | |
30 | * <li>The method must have at least one parameter argument</li> | |
31 | * </ol> | |
32 | * | |
33 | * It is good practice to define any custom transformers in their own class (a class can have more than one transformer method). | |
34 | * A transformer class should be thread-safe and not have any transitive state, meaning that it should not maintain state as | |
35 | * a result of a transformation. It is fine for transformers to have configuration state, such as in an XSLT or XQuery template file | |
36 | * (note that Mule already provides transformers for XSLT and XQuery). | |
37 | */ | |
38 | @Target(ElementType.METHOD) | |
39 | @Retention(RetentionPolicy.RUNTIME) | |
40 | @Documented | |
41 | public @interface Transformer | |
42 | { | |
43 | /** | |
44 | * The 'priorityWeighting property is used to resolve conflicts where there is more than one transformers that match | |
45 | * the selection criteria. 10 is the highest priority and 1 is the lowest. | |
46 | * | |
47 | * @return the priority weighting for this transformer. If the class defines more than one transform method, every transform | |
48 | * method will have the same weighting. | |
49 | */ | |
50 | int priorityWeighting() default 5; | |
51 | ||
52 | //TODO BL-140 add when we get support for Transformer mime types | |
53 | // String sourceMimeType() default MimeTypes.ANY; | |
54 | // | |
55 | // String resultMimeType() default MimeTypes.ANY; | |
56 | ||
57 | /** | |
58 | * SourceTypes define additional types that this transformer will accepts as a sourceType (beyond the method parameter). | |
59 | * At run time if the current message matches one of these source types, Mule will attempt to transform from | |
60 | * the source type to the method parameter type. This means that transformations can be chained. The user can create | |
61 | * other transformers to be a part of this chain. | |
62 | * | |
63 | * @return an array of class types which allow the transformer to be matched on | |
64 | */ | |
65 | Class[] sourceTypes() default {}; | |
66 | } |