/*******************************************************************************
* Copyright (c) 2001, 2005 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
* Jens Lukowski/Innoopract - initial renaming/restructuring
*
*******************************************************************************/
package org.eclipse.wst.sse.ui.internal.util;
/**
* The SortOperation takes a collection of objects and returns a sorted
* collection of these objects. Concrete instances of this class provide the
* criteria for the sorting of the objects based on the type of the objects.
*/
public abstract class Sorter {
/**
* Returns true if elementTwo is 'greater than' elementOne This is the
* 'ordering' method of the sort operation. Each subclass overides this
* method with the particular implementation of the 'greater than' concept
* for the objects being sorted.
*/
public abstract boolean compare(Object elementOne, Object elementTwo);
/**
* Sort the objects in sorted collection and return that collection.
*/
private Object[] quickSort(Object[] sortedCollection, int left, int right) {
int originalLeft = left;
int originalRight = right;
Object mid = sortedCollection[(left + right) / 2];
do {
while (compare(sortedCollection[left], mid))
left++;
while (compare(mid, sortedCollection[right]))
right--;
if (left <= right) {
Object tmp = sortedCollection[left];
sortedCollection[left] = sortedCollection[right];
sortedCollection[right] = tmp;
left++;
right--;
}
} while (left <= right);
if (originalLeft < right)
sortedCollection = quickSort(sortedCollection, originalLeft, right);
if (left < originalRight)
sortedCollection = quickSort(sortedCollection, left, originalRight);
return sortedCollection;
}
/**
* Return a new sorted collection from this unsorted collection. Sort
* using quick sort.
*/
public Object[] sort(Object[] unSortedCollection) {
int size = unSortedCollection.length;
Object[] sortedCollection = new Object[size];
//copy the array so can return a new sorted collection
System.arraycopy(unSortedCollection, 0, sortedCollection, 0, size);
if (size > 1)
quickSort(sortedCollection, 0, size - 1);
return sortedCollection;
}
}