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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.event;
21  
22  import org.apache.commons.lang.builder.ToStringBuilder;
23  import org.apache.mina.statemachine.context.StateContext;
24  
25  /**
26   * Represents an event which typically corresponds to a method call on a proxy.
27   * An event has an id and zero or more arguments typically corresponding to
28   * the method arguments. 
29   *
30   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
31   */
32  public class Event {
33      public static final String WILDCARD_EVENT_ID = "*";
34      
35      private final Object id;
36      private final StateContext context;
37      private final Object[] arguments;
38      
39      /**
40       * Creates a new {@link Event} with the specified id and no arguments.
41       * 
42       * @param id the event id.
43       * @param context the {@link StateContext} the event was triggered for.
44       */
45      public Event(Object id, StateContext context) {
46          this(id, context, new Object[0]);
47      }
48  
49      /**
50       * Creates a new {@link Event} with the specified id and arguments.
51       * 
52       * @param id the event id.
53       * @param context the {@link StateContext} the event was triggered for.
54       * @param arguments the event arguments.
55       */
56      public Event(Object id, StateContext context, Object[] arguments) {
57          if (id == null) {
58              throw new NullPointerException("id");
59          }
60          if (context == null) {
61              throw new NullPointerException("context");
62          }
63          if (arguments == null) {
64              throw new NullPointerException("arguments");
65          }
66          this.id = id;
67          this.context = context;
68          this.arguments = arguments;
69      }
70  
71      /**
72       * Returns the {@link StateContext} this {@link Event} was triggered for.
73       * 
74       * @return the {@link StateContext}.
75       */
76      public StateContext getContext() {
77          return context;
78      }
79  
80      /**
81       * Returns the id of this {@link Event}.
82       * 
83       * @return the id.
84       */
85      public Object getId() {
86          return id;
87      }
88  
89      /**
90       * Returns the arguments of this {@link Event}.
91       * 
92       * @return the arguments. Returns an empty array if this {@link Event} has 
93       *         no arguments.
94       */
95      public Object[] getArguments() {
96          return arguments;
97      }
98      
99      public String toString() {
100         return new ToStringBuilder(this)
101             .append("id", id)
102             .append("context", context)
103             .append("arguments", arguments)
104             .toString();
105     }
106 }