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1   /*
2    * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
3    * The software in this package is published under the terms of the CPAL v1.0
4    * license, a copy of which has been included with this distribution in the
5    * LICENSE.txt file.
6    */
7   package org.mule.util.counters;
8   
9   /**
10   * This interface is the interface implemented for all counter types. A Counter can
11   * represent a real counter or a virtual counter that will be computed using one or
12   * more other counters.<br/>
13   * <h3>Real counters</h3>
14   * are counters which represent real values. The user will call methods of such
15   * counters to modify the associated value of the counter.
16   * <h3>Computed counters</h3>
17   * are computed using one or more associated counters. Such counters represent
18   * operations computed on associated counters. Usually, these counters will never be
19   * used directly, but will only used to retrieve the computed values.
20   */
21  public interface Counter
22  {
23  
24      /**
25       * Accessor for the counter type.
26       * 
27       * @return the type of the counter
28       */
29      CounterFactory.Type getType();
30  
31      /**
32       * Accessor for the counter's name.
33       * 
34       * @return the name of the counter
35       */
36      String getName();
37  
38      /**
39       * Increment the counter's value by 1.0.
40       * 
41       * @return the new value of the counter
42       */
43      double increment();
44  
45      /**
46       * Increment the counter's value by the specified amount.
47       * 
48       * @param value the amount to increment the counter by
49       * @return the new value of the counter
50       */
51      double incrementBy(double value);
52  
53      /**
54       * Decrement the counter's value by 1.0.
55       * 
56       * @return the new value of the counter
57       */
58      double decrement();
59  
60      /**
61       * Set the counter's value to a new value.
62       * 
63       * @param value the new value of the counter
64       */
65      void setRawValue(double value);
66  
67      /**
68       * Compute and return the value of the counter.
69       * 
70       * @return the value of the counter
71       */
72      double nextValue();
73  
74  }