Copyright (c) 2000, 2011 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2011 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.ui.text;

import java.text.CharacterIterator;

import com.ibm.icu.text.BreakIterator;

import org.eclipse.core.runtime.Assert;



Breaks java text into word starts, also stops at line start and end. No
direction dependency.
Since:
3.0/**
 * Breaks java text into word starts, also stops at line start and end. No
 * direction dependency.
 *
 * @since 3.0
 */
public class JavaWordIterator extends BreakIterator {

	
The underlying java break iterator. It returns all breaks, including
before and after every whitespace.
/**
	 * The underlying java break iterator. It returns all breaks, including
	 * before and after every whitespace.
	 */
	private JavaBreakIterator fIterator;
	
The current index for the stateful operations. /** The current index for the stateful operations. */
	private int fIndex;

	
Creates a new word iterator.
/**
	 * Creates a new word iterator.
	 */
	public JavaWordIterator() {
		fIterator= new JavaBreakIterator();
		first();
	}

	/*
	 * @see java.text.BreakIterator#first()
	 */
	@Override
	public int first() {
		fIndex= fIterator.first();
		return fIndex;
	}

	/*
	 * @see java.text.BreakIterator#last()
	 */
	@Override
	public int last() {
		fIndex= fIterator.last();
		return fIndex;
	}

	/*
	 * @see java.text.BreakIterator#next(int)
	 */
	@Override
	public int next(int n) {
		int next= 0;
		while (--n > 0 && next != DONE) {
			next= next();
		}
		return next;
	}

	/*
	 * @see java.text.BreakIterator#next()
	 */
	@Override
	public int next() {
		fIndex= following(fIndex);
		return fIndex;
	}

	/*
	 * @see java.text.BreakIterator#previous()
	 */
	@Override
	public int previous() {
		fIndex= preceding(fIndex);
		return fIndex;
	}


	/*
	 * @see java.text.BreakIterator#preceding(int)
	 */
	@Override
	public int preceding(int offset) {
		int first= fIterator.preceding(offset);
		if (isWhitespace(first, offset)) {
			int second= fIterator.preceding(first);
			if (second != DONE && !isDelimiter(second, first))
				return second;
		}
		return first;
	}

	/*
	 * @see java.text.BreakIterator#following(int)
	 */
	@Override
	public int following(int offset) {
		int first= fIterator.following(offset);
		if (eatFollowingWhitespace(offset, first)) {
			int second= fIterator.following(first);
			if (isWhitespace(first, second))
				return second;
		}
		return first;
	}

	private boolean eatFollowingWhitespace(int offset, int exclusiveEnd) {
		if (exclusiveEnd == DONE || offset == DONE)
			return false;

		if (isWhitespace(offset, exclusiveEnd))
			return false;
		if (isDelimiter(offset, exclusiveEnd))
			return false;

		return true;
	}

	
Returns true if the given sequence into the underlying text
represents a delimiter, false otherwise.
Params:
offset – the offset
exclusiveEnd – the end offset
Returns:
true if the given range is a delimiter/**
	 * Returns <code>true</code> if the given sequence into the underlying text
	 * represents a delimiter, <code>false</code> otherwise.
	 *
	 * @param offset the offset
	 * @param exclusiveEnd the end offset
	 * @return <code>true</code> if the given range is a delimiter
	 */
	private boolean isDelimiter(int offset, int exclusiveEnd) {
		if (exclusiveEnd == DONE || offset == DONE)
			return false;

		Assert.isTrue(offset >= 0);
		Assert.isTrue(exclusiveEnd <= getText().getEndIndex());
		Assert.isTrue(exclusiveEnd > offset);

		CharSequence seq= fIterator.fText;

		while (offset < exclusiveEnd) {
			char ch= seq.charAt(offset);
			if (ch != '\n' && ch != '\r')
				return false;
			offset++;
		}

		return true;
	}

	
Returns true if the given sequence into the underlying text
represents whitespace, but not a delimiter, false otherwise.
Params:
offset – the offset
exclusiveEnd – the end offset
Returns:
true if the given range is whitespace/**
	 * Returns <code>true</code> if the given sequence into the underlying text
	 * represents whitespace, but not a delimiter, <code>false</code> otherwise.
	 *
	 * @param offset the offset
	 * @param exclusiveEnd the end offset
	 * @return <code>true</code> if the given range is whitespace
	 */
	private boolean isWhitespace(int offset, int exclusiveEnd) {
		if (exclusiveEnd == DONE || offset == DONE)
			return false;

		Assert.isTrue(offset >= 0);
		Assert.isTrue(exclusiveEnd <= getText().getEndIndex());
		Assert.isTrue(exclusiveEnd > offset);

		CharSequence seq= fIterator.fText;

		while (offset < exclusiveEnd) {
			char ch= seq.charAt(offset);
			if (!Character.isWhitespace(ch))
				return false;
			if (ch == '\n' || ch == '\r')
				return false;
			offset++;
		}

		return true;
	}

	/*
	 * @see java.text.BreakIterator#current()
	 */
	@Override
	public int current() {
		return fIndex;
	}

	/*
	 * @see java.text.BreakIterator#getText()
	 */
	@Override
	public CharacterIterator getText() {
		return fIterator.getText();
	}

	
Sets the text as CharSequence.
Params:
newText – the new text/**
	 * Sets the text as <code>CharSequence</code>.
	 * @param newText the new text
	 */
	public void setText(CharSequence newText) {
		fIterator.setText(newText);
		first();
	}

	/*
	 * @see java.text.BreakIterator#setText(java.text.CharacterIterator)
	 */
	@Override
	public void setText(CharacterIterator newText) {
		fIterator.setText(newText);
		first();
	}

	/*
	 * @see java.text.BreakIterator#setText(java.lang.String)
	 */
	@Override
	public void setText(String newText) {
		setText((CharSequence) newText);
	}

}