/*******************************************************************************
* Copyright (c) 2006 Business Objects Software Limited and others.
* All rights reserved.
* This file is made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Business Objects Software Limited - initial API and implementation based on Eclipse 3.1.2 code for
* /org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/SequenceCharacterIterator.java
* Eclipse source is available at: http://www.eclipse.org/downloads/
*******************************************************************************/
/*
* SequenceCharacterIterator.java
* Creation date: Feb 24, 2006.
* By: Edward Lam
*/
package org.openquark.cal.eclipse.ui.text;
import java.text.CharacterIterator;
import org.eclipse.core.runtime.Assert;
/**
* A <code>CharSequence</code> based implementation of <code>CharacterIterator</code>.
*/
public class SequenceCharacterIterator implements CharacterIterator {
private int fIndex = -1;
private final CharSequence fSequence;
private final int fFirst;
private final int fLast;
private void invariant() {
Assert.isTrue(fIndex >= fFirst);
Assert.isTrue(fIndex <= fLast);
}
/**
* Creates an iterator for the entire sequence.
*
* @param sequence the sequence backing this iterator
*/
public SequenceCharacterIterator(CharSequence sequence) {
this(sequence, 0);
}
/**
* Creates an iterator.
*
* @param sequence the sequence backing this iterator
* @param first the first character to consider
* @throws IllegalArgumentException if the indices are out of bounds
*/
public SequenceCharacterIterator(CharSequence sequence, int first) throws IllegalArgumentException {
this(sequence, first, sequence.length());
}
/**
* Creates an iterator.
*
* @param sequence the sequence backing this iterator
* @param first the first character to consider
* @param last the last character index to consider
* @throws IllegalArgumentException if the indices are out of bounds
*/
public SequenceCharacterIterator(CharSequence sequence, int first, int last) throws IllegalArgumentException {
if (sequence == null) {
throw new NullPointerException();
}
if (first < 0 || first > last) {
throw new IllegalArgumentException();
}
if (last > sequence.length()) {
throw new IllegalArgumentException();
}
fSequence = sequence;
fFirst = first;
fLast = last;
fIndex = first;
invariant();
}
/*
* @see java.text.CharacterIterator#first()
*/
public char first() {
return setIndex(getBeginIndex());
}
/*
* @see java.text.CharacterIterator#last()
*/
public char last() {
if (fFirst == fLast) {
return setIndex(getEndIndex());
} else {
return setIndex(getEndIndex() - 1);
}
}
/*
* @see java.text.CharacterIterator#current()
*/
public char current() {
if (fIndex >= fFirst && fIndex < fLast) {
return fSequence.charAt(fIndex);
} else {
return DONE;
}
}
/*
* @see java.text.CharacterIterator#next()
*/
public char next() {
return setIndex(Math.min(fIndex + 1, getEndIndex()));
}
/*
* @see java.text.CharacterIterator#previous()
*/
public char previous() {
if (fIndex > getBeginIndex()) {
return setIndex(fIndex - 1);
} else {
return DONE;
}
}
/*
* @see java.text.CharacterIterator#setIndex(int)
*/
public char setIndex(int position) {
if (position >= getBeginIndex() && position <= getEndIndex()) {
fIndex = position;
} else {
throw new IllegalArgumentException();
}
invariant();
return current();
}
/*
* @see java.text.CharacterIterator#getBeginIndex()
*/
public int getBeginIndex() {
return fFirst;
}
/*
* @see java.text.CharacterIterator#getEndIndex()
*/
public int getEndIndex() {
return fLast;
}
/*
* @see java.text.CharacterIterator#getIndex()
*/
public int getIndex() {
return fIndex;
}
/*
* @see java.text.CharacterIterator#clone()
*/
@Override
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException e) {
throw new InternalError();
}
}
}