net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/text/DocumentCharacterIterator.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2004 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.ui.text;
  12
  13 import java.text.CharacterIterator;
  14
  15 import org.eclipse.jface.text.Assert;
  16 import org.eclipse.jface.text.BadLocationException;
  17 import org.eclipse.jface.text.IDocument;
  18
  19
  20 /**
  21  * An <code>IDocument</code> based implementation of <code>CharacterIterator</code>.
  22  *
  23  * @since 3.0
  24  */
  25 public class DocumentCharacterIterator implements CharacterIterator, CharSequence {
  26
  27         private int fIndex= -1;
  28         private final IDocument fDocument;
  29         private final int fFirst;
  30         private final int fLast;
  31
  32         private void invariant() {
  33                 Assert.isTrue(fIndex >= fFirst);
  34                 Assert.isTrue(fIndex <= fLast);
  35         }
  36
  37         /**
  38          * Creates an iterator for the entire sequence.
  39          *
  40          * @param sequence the sequence backing this iterator
  41          */
  42         public DocumentCharacterIterator(IDocument sequence) {
  43                 this(sequence, 0);
  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          * @throws IllegalArgumentException if the indices are out of bounds
  52          */
  53         public DocumentCharacterIterator(IDocument sequence, int first) throws IllegalArgumentException {
  54                 this(sequence, first, sequence.getLength());
  55         }
  56
  57         /**
  58          * Creates an iterator.
  59          *
  60          * @param sequence the sequence backing this iterator
  61          * @param first the first character to consider
  62          * @param last the last character index to consider
  63          * @throws IllegalArgumentException if the indices are out of bounds
  64          */
  65         public DocumentCharacterIterator(IDocument sequence, int first, int last) throws IllegalArgumentException {
  66                 if (sequence == null)
  67                         throw new NullPointerException();
  68                 if (first < 0 || first > last)
  69                         throw new IllegalArgumentException();
  70                 if (last > sequence.getLength())
  71                         throw new IllegalArgumentException();
  72                 fDocument= sequence;
  73                 fFirst= first;
  74                 fLast= last;
  75                 fIndex= first;
  76                 invariant();
  77         }
  78
  79         /*
  80          * @see java.text.CharacterIterator#first()
  81          */
  82         public char first() {
  83                 return setIndex(getBeginIndex());
  84         }
  85
  86         /*
  87          * @see java.text.CharacterIterator#last()
  88          */
  89         public char last() {
  90                 if (fFirst == fLast)
  91                         return setIndex(getEndIndex());
  92                 else
  93                         return setIndex(getEndIndex() - 1);
  94         }
  95
  96         /*
  97          * @see java.text.CharacterIterator#current()
  98          */
  99         public char current() {
 100                 if (fIndex >= fFirst && fIndex < fLast)
 101                         try {
 102                                 return fDocument.getChar(fIndex);
 103                         } catch (BadLocationException e) {
 104                                 // ignore
 105                         }
 106                 return DONE;
 107         }
 108
 109         /*
 110          * @see java.text.CharacterIterator#next()
 111          */
 112         public char next() {
 113                 return setIndex(Math.min(fIndex + 1, getEndIndex()));
 114         }
 115
 116         /*
 117          * @see java.text.CharacterIterator#previous()
 118          */
 119         public char previous() {
 120                 if (fIndex > getBeginIndex()) {
 121                         return setIndex(fIndex - 1);
 122                 } else {
 123                         return DONE;
 124                 }
 125         }
 126
 127         /*
 128          * @see java.text.CharacterIterator#setIndex(int)
 129          */
 130         public char setIndex(int position) {
 131                 if (position >= getBeginIndex() && position <= getEndIndex())
 132                         fIndex= position;
 133                 else
 134                         throw new IllegalArgumentException();
 135
 136                 invariant();
 137                 return current();
 138         }
 139
 140         /*
 141          * @see java.text.CharacterIterator#getBeginIndex()
 142          */
 143         public int getBeginIndex() {
 144                 return fFirst;
 145         }
 146
 147         /*
 148          * @see java.text.CharacterIterator#getEndIndex()
 149          */
 150         public int getEndIndex() {
 151                 return fLast;
 152         }
 153
 154         /*
 155          * @see java.text.CharacterIterator#getIndex()
 156          */
 157         public int getIndex() {
 158                 return fIndex;
 159         }
 160
 161         /*
 162          * @see java.text.CharacterIterator#clone()
 163          */
 164         public Object clone() {
 165                 try {
 166                         return super.clone();
 167                 } catch (CloneNotSupportedException e) {
 168                         throw new InternalError();
 169                 }
 170         }
 171
 172         /*
 173          * @see java.lang.CharSequence#length()
 174          */
 175         public int length() {
 176                 return getEndIndex() - getBeginIndex();
 177         }
 178
 179         /*
 180          * @see java.lang.CharSequence#charAt(int)
 181          */
 182         public char charAt(int index) {
 183                 if (index >= getBeginIndex() && index <= getEndIndex())
 184                         try {
 185                                 return fDocument.getChar(index);
 186                         } catch (BadLocationException e) {
 187                                 // ignore and return DONE
 188                                 return DONE;
 189                         }
 190                 else
 191                         throw new IllegalArgumentException();
 192         }
 193
 194         /*
 195          * @see java.lang.CharSequence#subSequence(int, int)
 196          */
 197         public CharSequence subSequence(int start, int end) {
 198                 return new DocumentCharacterIterator(fDocument, getBeginIndex() + start, getBeginIndex() + start + end);
 199         }
 200 }