bundles/org.simantics.scl.ui/src/org/simantics/scl/ui/editor2/iterator/SequenceCharacterIterator.java

   1 package org.simantics.scl.ui.editor2.iterator;
   2
   3 import java.text.CharacterIterator;
   4
   5 import org.eclipse.core.runtime.Assert;
   6
   7
   8
   9 /**
  10  * A <code>CharSequence</code> based implementation of <code>CharacterIterator</code>.
  11  *
  12  * @since 3.0
  13  */
  14 public class SequenceCharacterIterator implements CharacterIterator {
  15
  16         private int fIndex= -1;
  17         private final CharSequence fSequence;
  18         private final int fFirst;
  19         private final int fLast;
  20
  21         private void invariant() {
  22                 Assert.isTrue(fIndex >= fFirst);
  23                 Assert.isTrue(fIndex <= fLast);
  24         }
  25
  26         /**
  27          * Creates an iterator for the entire sequence.
  28          *
  29          * @param sequence the sequence backing this iterator
  30          */
  31         public SequenceCharacterIterator(CharSequence sequence) {
  32                 this(sequence, 0);
  33         }
  34
  35         /**
  36          * Creates an iterator.
  37          *
  38          * @param sequence the sequence backing this iterator
  39          * @param first the first character to consider
  40          * @throws IllegalArgumentException if the indices are out of bounds
  41          */
  42         public SequenceCharacterIterator(CharSequence sequence, int first) throws IllegalArgumentException {
  43                 this(sequence, first, sequence.length());
  44         }
  45
  46         /**
  47          * Creates an iterator.
  48          *
  49          * @param sequence the sequence backing this iterator
  50          * @param first the first character to consider
  51          * @param last the last character index to consider
  52          * @throws IllegalArgumentException if the indices are out of bounds
  53          */
  54         public SequenceCharacterIterator(CharSequence sequence, int first, int last) throws IllegalArgumentException {
  55                 if (sequence == null)
  56                         throw new NullPointerException();
  57                 if (first < 0 || first > last)
  58                         throw new IllegalArgumentException();
  59                 if (last > sequence.length())
  60                         throw new IllegalArgumentException();
  61                 fSequence= sequence;
  62                 fFirst= first;
  63                 fLast= last;
  64                 fIndex= first;
  65                 invariant();
  66         }
  67
  68         /*
  69          * @see java.text.CharacterIterator#first()
  70          */
  71         public char first() {
  72                 return setIndex(getBeginIndex());
  73         }
  74
  75         /*
  76          * @see java.text.CharacterIterator#last()
  77          */
  78         public char last() {
  79                 if (fFirst == fLast)
  80                         return setIndex(getEndIndex());
  81                 else
  82                         return setIndex(getEndIndex() - 1);
  83         }
  84
  85         /*
  86          * @see java.text.CharacterIterator#current()
  87          */
  88         public char current() {
  89                 if (fIndex >= fFirst && fIndex < fLast)
  90                         return fSequence.charAt(fIndex);
  91                 else
  92                         return DONE;
  93         }
  94
  95         /*
  96          * @see java.text.CharacterIterator#next()
  97          */
  98         public char next() {
  99                 return setIndex(Math.min(fIndex + 1, getEndIndex()));
 100         }
 101
 102         /*
 103          * @see java.text.CharacterIterator#previous()
 104          */
 105         public char previous() {
 106                 if (fIndex > getBeginIndex()) {
 107                         return setIndex(fIndex - 1);
 108                 } else {
 109                         return DONE;
 110                 }
 111         }
 112
 113         /*
 114          * @see java.text.CharacterIterator#setIndex(int)
 115          */
 116         public char setIndex(int position) {
 117                 if (position >= getBeginIndex() && position <= getEndIndex())
 118                         fIndex= position;
 119                 else
 120                         throw new IllegalArgumentException();
 121
 122                 invariant();
 123                 return current();
 124         }
 125
 126         /*
 127          * @see java.text.CharacterIterator#getBeginIndex()
 128          */
 129         public int getBeginIndex() {
 130                 return fFirst;
 131         }
 132
 133         /*
 134          * @see java.text.CharacterIterator#getEndIndex()
 135          */
 136         public int getEndIndex() {
 137                 return fLast;
 138         }
 139
 140         /*
 141          * @see java.text.CharacterIterator#getIndex()
 142          */
 143         public int getIndex() {
 144                 return fIndex;
 145         }
 146
 147         /*
 148          * @see java.text.CharacterIterator#clone()
 149          */
 150         @Override
 151         public Object clone() {
 152                 try {
 153                         return super.clone();
 154                 } catch (CloneNotSupportedException e) {
 155                         throw new InternalError();
 156                 }
 157         }
 158 }