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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License.
18   *
19   */
20  package org.apache.mina.statemachine.annotation;
21  
22  import java.lang.annotation.ElementType;
23  import java.lang.annotation.Retention;
24  import java.lang.annotation.RetentionPolicy;
25  import java.lang.annotation.Target;
26  
27  import org.apache.mina.statemachine.StateMachine;
28  import org.apache.mina.statemachine.event.Event;
29  
30  /**
31   * Annotation used on methods to indicate that the method handles a specific
32   * kind of event when in a specific state.
33   *
34   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
35   */
36  @Retention(RetentionPolicy.RUNTIME)
37  @Target(ElementType.METHOD)
38  @TransitionAnnotation(Transitions.class)
39  public @interface Transition {
40      public static final String SELF = "__self__";
41  
42      /**
43       * Specifies the ids of one or more events handled by the annotated method. If
44       * not specified the handler method will be executed for any event.
45       * 
46       * @return the ids of the handled events
47       */
48      String[] on() default Event.WILDCARD_EVENT_ID;
49  
50      /**
51       * The id of the state or states that this handler applies to. Must be
52       * specified.
53       * 
54       * @return the ids of the handled states
55       */
56      String[] in();
57  
58      /**
59       * The id of the state the {@link StateMachine} should move to next after
60       * executing the annotated method. If not specified the {@link StateMachine}
61       * will remain in the same state.
62       * 
63       * @return the id of the next state
64       */
65      String next() default SELF;
66  
67      /**
68       * The weight used to order handler annotations which match the same event 
69       * in the same state. Transitions with lower weight will be matched first. The
70       * default weight is 0.
71       * 
72       * @return the weight used to order the handler
73       */
74      int weight() default 0;
75  }