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/*******************************************************************************
* Copyright (c) 2001, 2009 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.core.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 iff elementTwo is 'greater than' elementOne. This is the
* 'ordering' method of the sort operation. Each subclass overrides this
* method with the particular implementation of the 'greater than' concept
* for the objects being sorted. If elementOne and elementTwo are
* equivalent in terms of their sorting order, this method must return
* 'false'.
*/
public abstract boolean compare(Object elementOne, Object elementTwo);
/**
* Sort the objects in the array and return the array.
*/
private Object[] quickSort(Object[] array, int left, int right) {
int originalLeft = left;
int originalRight = right;
Object mid = array[(left + right) / 2];
do {
while (compare(array[left], mid))
left++;
while (compare(mid, array[right]))
right--;
if (left <= right) {
Object tmp = array[left];
array[left] = array[right];
array[right] = tmp;
left++;
right--;
}
} while (left <= right);
if (originalLeft < right)
array = quickSort(array, originalLeft, right);
if (left < originalRight)
array = quickSort(array, left, originalRight);
return array;
}
/**
* Return a new (quick)sorted array from this unsorted array. The original
* array is not modified.
*/
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;
}
}
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