ListComparator.java

/*******************************************************************************
 * Copyright (c) 2007, 2010 Intel 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:
 * Intel Corporation - Initial API and implementation
 *******************************************************************************/
package org.eclipse.cdt.core.settings.model.util;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

@SuppressWarnings("rawtypes")
public class ListComparator {
	private static Comparator fDefaultComparator; 
	
	public static Comparator getDefaultComparator(){
		if(fDefaultComparator == null)
			fDefaultComparator = new Comparator();
		return fDefaultComparator;
		
	}
	public static List[] compare(Object a1[], Object a2[]){
		return compare(a1, a2, getDefaultComparator());
	}

	public static List[] compare(Object a1[], Object a2[], Comparator c){
		List added = getAdded(a1, a2, c);
		List removed = getAdded(a2, a1, c);
		
		if(added == null && removed == null)
			return null;

		return new List[]{added, removed};
	}

	public static List getAdded(Object a1[], Object a2[]){
		return getAdded(a1, a2, getDefaultComparator());
	}

	public static List getAdded(Object a1[], Object a2[], Comparator c){
		if(a1 == null || a1.length == 0)
			return null;
		if(a2 == null || a2.length == 0){
			List<Object> list = new ArrayList<Object>(a1.length);
			for(int i = 0; i < a1.length; i++){
				list.add(a1[i]);
			}
			return list;
		}
		
		List<Object> list = new ArrayList<Object>(a1.length);
		Object o1;
		for(int i = 0; i < a1.length; i++){
			o1 = a1[i];
			for(int j = 0; j < a2.length; j++){
				if(!c.equal(o1, a2[j]))
					list.add(o1);
			}
		}
		
		return list.size() != 0 ? list : null;
	}
	
	@SuppressWarnings("unchecked")
	public static boolean match(Object a1[], Object a2[], Comparator c){
		if(a1 == null)
			return a2 == null;

		if(a2 == null)
			return false;
		
		if(a1.length != a2.length)
			return false;
		
		int size = a1.length;
		List list = new ArrayList(Arrays.asList(a1));
		List otherList = new ArrayList(Arrays.asList(a2));
		for(int i = size - 1; i >= 0; i--){
			Object o1 = list.remove(i);
			int j = i;
			for(; j >= 0; j--){
				if(c.equal(o1, otherList.get(j))){
					otherList.remove(j);
					break;
				}
			}
			
			if(j < 0)
				return false;
		}

		return true;
	}
	
	public static int indexOf(Object o, Object[] a){
		return indexOf(o, a, getDefaultComparator());
	}

	public static int indexOf(Object o, Object[] a, Comparator c){
		for(int i = 0; i < a.length; i++){
			if(c.equal(a[i], o))
				return i;
		}
		return -1;
	}

	public static boolean haveMatches(Object[] a1 , Object[] a2){
		return haveMatches(a1, a2, getDefaultComparator());
	}

	public static boolean haveMatches(Object[] a1 , Object[] a2, Comparator c){
		for(int i = 0; i < a1.length; i++){
			if(indexOf(a1[i], a2, c) != -1)
				return true;
		}
		return false;
	}

}