1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
/*******************************************************************************
* Copyright (c) 2000, 2004 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Common Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/cpl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.team.internal.core;
/**
* 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 is 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;
}
}
|
