01 /*
02 * Copyright 2010-2012 the original author or authors.
03 *
04 * Licensed under the Apache License, Version 2.0 (the "License")
05 * you may not use this file except in compliance with the License.
06 * You may obtain a copy of the License at
07 *
08 * http://www.apache.org/licenses/LICENSE-2.0
09 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package griffon.transform;
18
19 import org.codehaus.groovy.transform.GroovyASTTransformationClass;
20
21 import java.lang.annotation.ElementType;
22 import java.lang.annotation.Retention;
23 import java.lang.annotation.RetentionPolicy;
24 import java.lang.annotation.Target;
25
26 /**
27 * <p>Annotates a class.</p>
28 * <p>This transformation provides a convenient way to register PropertyChangeListeners
29 * on an observable bean by leveraging Groovy's closures and the Groovy cast operator.</p>
30 *
31 * <p>The following code exemplifies what must be written by hand in order to register a pair
32 * of PropertyChangeListeners. One of them is a catch-all handler while the second is property specific.
33 * <pre>
34 * import groovy.beans.Bindable
35 * import java.beans.PropertyChangeListener
36 *
37 * class MyModel {
38 * @Bindable String name
39 * @Bindable String lastname
40 *
41 * def snoopAll = { evt -> ... }
42 *
43 * MyModel() {
44 * addPropertyChangeListener(snoopAll as PropertyChangeListener)
45 * addPropertyChangeListener('lastname', {
46 * controller.someAction(it)
47 * } as PropertyChangeListener)
48 * }
49 * }
50 * </pre>
51 *
52 * <p>Applying @PropertyListener to the previous snippet results in the following code</p>
53 * <pre>
54 * import griffon.transform.PropertyListener
55 * import groovy.beans.Bindable
56 *
57 * @PropertyListener(snoopAll)
58 * class MyModel {
59 * @Bindable String name
60 *
61 * @Bindable
62 * @PropertyListener({controller.someAction(it)})
63 * String lastname
64 *
65 * def snoopAll = { evt -> ... }
66 * }
67 * </pre>
68 *
69 * Any closures found as the annotation's value will be either transformed
70 * into inner classes that implement PropertyChangeListener (when the value
71 * is a closure defined in place) or be casted as a proxy of PropertyChangeListener
72 * (when the value is a property reference found in the same class).<p>
73 * List of closures are also supported.
74 *
75 * @author Andres Almiray
76 * @see org.codehaus.griffon.ast.PropertyListenerASTTransformation
77 */
78 @Retention(RetentionPolicy.SOURCE)
79 @Target({ElementType.FIELD, ElementType.TYPE})
80 @GroovyASTTransformationClass("org.codehaus.griffon.ast.PropertyListenerASTTransformation")
81 public @interface PropertyListener {
82 String value();
83 }
|