MouseWheelEvent


1   /*
2    *    Copyright 2004 Dusty Phillips
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
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  package com.buchuki.ensmer.input.event;
17  
18  import java.awt.event.*;
19  
20  /**
21   * Represents a MouseWheel in any direction. It can model an event that
22   * has occured or an event that can occur. If no actual event is represented,
23   * getInputEvent() will return null;
24   *
25   * @author Dusty Phillips [dusty@buchuki.com]
26   */
27  public class MouseWheelEvent extends EnsmerMouseEvent implements Measurable {
28  
29      /**
30       * Create a MouseWheelEvent. 
31       */
32      public MouseWheelEvent() {
33          super();
34      }
35  
36      /**
37       * Create a MouseWheelEvent with a reference to the actual MouseWheelEvent
38       * that occured. This constructor is used when an actual InputEvent has
39       * been generated. The button is retrieved from the event itself.
40       *
41       * @param event an InputEvent that was generated
42       */
43      public MouseWheelEvent(java.awt.event.MouseWheelEvent   event) {
44          super(event);
45      }
46      
47      /**
48       * Get the magnitude of the wheel rotation. This method call is only valid
49       * if the event was instantiated with a genuine MouseWheelEvent, otherwise
50       * an IllegalStateException is thrown
51       *
52       * @return the magnitude of the wheelmovement
53       * @throws IllegalStateException if this doesn't represent an actual 
54       * InputEvent
55       */
56      public float getMagnitude() {
57          java.awt.event.MouseWheelEvent   evt = (java.awt.event.MouseWheelEvent  ) getInputEvent();
58          if (evt == null) {
59              throw new IllegalStateException  ("No MouseWheelEvent to retrieve magnitude from");
60          }
61          return evt.getWheelRotation();
62      }
63  
64      /**
65       * Determine if this event is equal to another object. Two events are
66       * equal if they have the same class in this case. 
67       *
68       * @param obj the object to compare to
69       * @return true if the object is equal to this object
70       */
71      @Override  
72      public boolean equals(Object   obj) {
73          return getClass().equals(obj.getClass());
74      }
75  
76      /**
77       * Determine the hashcode for this event. Events will not likely be
78       * hashed, but this keeps the equals() contract.
79       *
80       * @return the hashCode for this object
81       */
82       @Override  
83      public int hashCode() {
84          return getClass().hashCode();
85      }
86  
87  }
88
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