1/*
2******************************************************************************
3* Copyright (C) 1996-2010, International Business Machines Corporation and   *
4* others. All Rights Reserved.                                               *
5******************************************************************************
6*/
7
8package com.ibm.icu.util;
9
10/**
11 * <p>Interface for enabling iteration over sets of &lt;int index, int value>,
12 * where index is the sorted integer index in ascending order and value, its
13 * associated integer value.</p>
14 * <p>The result for each iteration is the consecutive range of
15 * &lt;int index, int value> with the same value. Result is represented by
16 * &lt;start, limit, value> where</p>
17 * <ul>
18 * <li> start is the starting integer of the result range
19 * <li> limit is 1 after the maximum integer that follows start, such that
20 *      all integers between start and (limit - 1), inclusive, have the same
21 *      associated integer value.
22 * <li> value is the integer value that all integers from start to (limit - 1)
23 *      share in common.
24 * </ul>
25 * <p>
26 * Hence value(start) = value(start + 1) = .... = value(start + n) = .... =
27 * value(limit - 1). However value(start -1) != value(start) and
28 * value(limit) != value(start).
29 * </p>
30 * <p>Most implementations will be created by factory methods, such as the
31 * character type iterator in UCharacter.getTypeIterator. See example below.
32 * </p>
33 * Example of use:<br>
34 * <pre>
35 * RangeValueIterator iterator = UCharacter.getTypeIterator();
36 * RangeValueIterator.Element result = new RangeValueIterator.Element();
37 * while (iterator.next(result)) {
38 *     System.out.println("Codepoint \\u" +
39 *                        Integer.toHexString(result.start) +
40 *                        " to codepoint \\u" +
41 *                        Integer.toHexString(result.limit - 1) +
42 *                        " has the character type " + result.value);
43 * }
44 * </pre>
45 * @author synwee
46 * @stable ICU 2.6
47 */
48public interface RangeValueIterator
49{
50    // public inner class ---------------------------------------------
51
52    /**
53    * Return result wrapper for com.ibm.icu.util.RangeValueIterator.
54    * Stores the start and limit of the continous result range and the
55    * common value all integers between [start, limit - 1] has.
56    * @stable ICU 2.6
57    */
58    public class Element
59    {
60        // public data member ---------------------------------------------
61
62        /**
63        * Starting integer of the continuous result range that has the same
64        * value
65        * @stable ICU 2.6
66        */
67        public int start;
68        /**
69        * (End + 1) integer of continuous result range that has the same
70        * value
71        * @stable ICU 2.6
72        */
73        public int limit;
74        /**
75        * Gets the common value of the continous result range
76        * @stable ICU 2.6
77        */
78        public int value;
79
80        // public constructor --------------------------------------------
81
82        /**
83         * Empty default constructor to make javadoc happy
84         * @stable ICU 2.4
85         */
86        public Element()
87        {
88        }
89    }
90
91    // public methods -------------------------------------------------
92
93    /**
94    * <p>Returns the next maximal result range with a common value and returns
95    * true if we are not at the end of the iteration, false otherwise.</p>
96    * <p>If this returns a false, the contents of elements will not
97    * be updated.</p>
98    * @param element for storing the result range and value
99    * @return true if we are not at the end of the iteration, false otherwise.
100    * @see Element
101    * @stable ICU 2.6
102    */
103    public boolean next(Element element);
104
105    /**
106    * Resets the iterator to the beginning of the iteration.
107    * @stable ICU 2.6
108    */
109    public void reset();
110}
111