01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * http://www.apache.org/licenses/LICENSE-2.0
10: *
11: * Unless required by applicable law or agreed to in writing, software
12: * distributed under the License is distributed on an "AS IS" BASIS,
13: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14: * See the License for the specific language governing permissions and
15: * limitations under the License.
16: *
17: * $Header:$
18: */
19: package org.apache.beehive.controls.api.events;
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: * The EventSet annotation type is used to mark an interface that defines a group of events
28: * associated with a Java Control. By convention, event interfaces are defined as inner
29: * classes on the Java Control public interface. Each method defined within a
30: * event interface indicates an event that can be delivered by the control.
31: * <p>
32: * Here is a simple example:
33: * <code><pre>
34: * public interface MyControl extends org.apache.beehive.controls.api.Control
35: * {
36: * <sp>@EventSet
37: * public interface MyEvents
38: * {
39: * public void anEvent();
40: * }
41: *
42: * ...
43: * }
44: * </pre></code>
45: * This will declare an event interface named <code>MyEvents</code> that declares a single
46: * event: <code>anEvent</code>
47: *
48: * The declaration of an EventSet for a control also means that the associated Control
49: * JavaBean will have listener registration/deregistration APIs. The name of these
50: * APIs will be <i>add/remove<EventSetName>Listener</i>, and the argument will be an
51: * listener instance that implements the EventSet interface.
52: * <p>
53: * The above example would result in the following APIs on <code>MyControlBean</code>
54: *
55: * <code><pre>
56: * public class MyControlBean implements MyControl
57: * {
58: * ...
59: * public void addMyEventsListener(MyEvents listener) { ... }
60: * public void removeMyEventsListener(MyEvents listener) { ... }
61: * </pre></code>
62: */
63: @Retention(RetentionPolicy.RUNTIME)
64: @Target({ElementType.TYPE})
65: public @interface EventSet {
66: /**
67: * Defines whether the events defined by the interface are unicast events. A unicast
68: * event set may have only a single listener registered to receive events for any
69: * given bean instance. Any attempt to register additional listeners will result in
70: * a <code>java.util.TooManyListenersException</code> being thrown by the event
71: * listener registration method.
72: * <p>
73: * If an event set provides multicast support (the default), then it may only declare
74: * event methods that have a <code>void</code> return type. Unicast event sets may
75: * support event return values, that will be provided by the (single) registered
76: * listener.
77: */
78: public boolean unicast() default false;
79: }
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