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1 /*
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2 File: AbstractIterator.d
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3
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4 Originally written by Doug Lea and released into the public domain.
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5 Thanks for the assistance and support of Sun Microsystems Labs, Agorics
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6 Inc, Loral, and everyone contributing, testing, and using this code.
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7
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8 History:
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9 Date Who What
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10 24Sep95 dl@cs.oswego.edu Create from tango.util.collection.d working file
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11 13Oct95 dl Changed protection statuses
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12 9Apr97 dl made class public
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13 */
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14
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15
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16 module tango.util.collection.impl.AbstractIterator;
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17
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18 private import tango.core.Exception;
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19
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20 private import tango.util.collection.model.View,
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21 tango.util.collection.model.GuardIterator;
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22
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23
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24
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25 /**
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26 *
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27 * A convenient base class for implementations of GuardIterator
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28 *
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29 author: Doug Lea
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30 * @version 0.93
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31 *
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32 * <P> For an introduction to this package see <A HREF="index.html"> Overview </A>.
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33 **/
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34
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35 public abstract class AbstractIterator(T) : GuardIterator!(T)
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36 {
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37 /**
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38 * The collection being enumerated
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39 **/
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40
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41 private View!(T) view;
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42
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43 /**
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44 * The version number of the collection we got upon construction
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45 **/
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46
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47 private uint mutation;
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48
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49 /**
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50 * The number of elements we think we have left.
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51 * Initialized to view.size() upon construction
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52 **/
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53
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54 private uint togo;
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55
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56
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57 protected this (View!(T) v)
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58 {
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59 view = v;
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60 togo = v.size();
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61 mutation = v.mutation();
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62 }
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63
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64 /**
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65 * Implements tango.util.collection.impl.Collection.CollectionIterator.corrupted.
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66 * Claim corruption if version numbers differ
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67 * See_Also: tango.util.collection.impl.Collection.CollectionIterator.corrupted
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68 **/
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69
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70 public final bool corrupted()
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71 {
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72 return mutation != view.mutation;
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73 }
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74
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75 /**
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76 * Implements tango.util.collection.impl.Collection.CollectionIterator.numberOfRemaingingElements.
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77 * See_Also: tango.util.collection.impl.Collection.CollectionIterator.remaining
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78 **/
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79 public final uint remaining()
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80 {
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81 return togo;
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82 }
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83
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84 /**
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85 * Implements tango.util.collection.model.Iterator.more.
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86 * Return true if remaining > 0 and not corrupted
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87 * See_Also: tango.util.collection.model.Iterator.more
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88 **/
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89 public final bool more()
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90 {
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91 return togo > 0 && mutation is view.mutation;
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92 }
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93
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94 /**
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95 * Subclass utility.
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96 * Tries to decrement togo, raising exceptions
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97 * if it is already zero or if corrupted()
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98 * Always call as the first line of get.
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99 **/
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100 protected final void decRemaining()
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101 {
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102 if (mutation != view.mutation)
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103 throw new CorruptedIteratorException ("Collection modified during iteration");
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104
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105 if (togo is 0)
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106 throw new NoSuchElementException ("exhausted enumeration");
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107
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108 --togo;
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109 }
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110 }
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111
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112
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113 public abstract class AbstractMapIterator(K, V) : AbstractIterator!(V), PairIterator!(K, V)
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114 {
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115 abstract V get (inout K key);
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116
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117 protected this (View!(V) c)
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118 {
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119 super (c);
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120 }
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121 }
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