/*******************************************************************************
 * Copyright (c) 2009, 2011 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.ui.workingsets;

import java.util.Comparator;

import com.ibm.icu.text.Collator;

import org.eclipse.ui.IWorkingSet;


/**
 * Comparator class to sort working sets, optionally keeping the default working set at the top.
 * 
 * @since 3.5
 */
public class WorkingSetComparator implements Comparator<IWorkingSet> {
	
	private Collator fCollator= Collator.getInstance();

	/**
	 * Boolean value to determine whether to keep default working set on the top while sorting.
	 */
	private boolean fIsOtherWorkingSetOnTop;


	/**
	 * Creates new instance of the working set comparator.
	 */
	public WorkingSetComparator() {
		fIsOtherWorkingSetOnTop= false;
	}

	/**
	 * Creates a new instance of working set comparator and initializes the boolean field value to
	 * the given value, which determines whether or not the default working set is kept on top while
	 * sorting the working sets.
	 * 
	 * @param isOtherWorkingSetOnTop <code>true</code> if default working set is to be retained at
	 *            the top, <code>false</code> otherwise
	 */
	public WorkingSetComparator(boolean isOtherWorkingSetOnTop) {
		fIsOtherWorkingSetOnTop= isOtherWorkingSetOnTop;
	}

	/**
	 * Returns <code>-1</code> if the first argument is the default working set, <code>1</code> if
	 * the second argument is the default working set and if the boolean
	 * <code>fIsOtherWorkingSetOnTop</code> is set, to keep the default working set on top while
	 * sorting.
	 * 
	 * @see Comparator#compare(Object, Object)
	 */
	public int compare(IWorkingSet w1, IWorkingSet w2) {

		if (fIsOtherWorkingSetOnTop && IWorkingSetIDs.OTHERS.equals(w1.getId()))
			return -1;
		
		if (fIsOtherWorkingSetOnTop && IWorkingSetIDs.OTHERS.equals(w2.getId()))
			return 1;
		
		return fCollator.compare(w1.getLabel(), w2.getLabel());
	}
}