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Java > Open Source Codes > org > eclipse > jdt > internal > core > util > ToStringSorter


1 /*******************************************************************************
2  * Copyright (c) 2000, 2007 IBM Corporation and others.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Eclipse Public License v1.0
5  * which accompanies this distribution, and is available at
6  * http://www.eclipse.org/legal/epl-v10.html
7  *
8  * Contributors:
9  * IBM Corporation - initial API and implementation
10  *******************************************************************************/
11 package org.eclipse.jdt.internal.core.util;
12
13 /**
14  * The SortOperation takes a collection of objects and returns
15  * a sorted collection of these objects. The sorting of these
16  * objects is based on their toString(). They are sorted in
17  * alphabetical order.
18  */
19 public class ToStringSorter {
20     Object JavaDoc[] sortedObjects;
21     String JavaDoc[] sortedStrings;
22 /**
23  * Returns true if stringTwo is 'greater than' stringOne
24  * This is the 'ordering' method of the sort operation.
25  */
26 public boolean compare(String JavaDoc stringOne, String JavaDoc stringTwo) {
27     return stringOne.compareTo(stringTwo) < 0;
28 }
29 /**
30  * Sort the objects in sorted collection and return that collection.
31  */
32 private void quickSort(int left, int right) {
33     int originalLeft = left;
34     int originalRight = right;
35     int midIndex = left + (right - left) / 2;
36     String JavaDoc midToString = this.sortedStrings[midIndex];
37     
38     do {
39         while (compare(this.sortedStrings[left], midToString))
40             left++;
41         while (compare(midToString, this.sortedStrings[right]))
42             right--;
43         if (left <= right) {
44             Object JavaDoc tmp = this.sortedObjects[left];
45             this.sortedObjects[left] = this.sortedObjects[right];
46             this.sortedObjects[right] = tmp;
47             String JavaDoc tmpToString = this.sortedStrings[left];
48             this.sortedStrings[left] = this.sortedStrings[right];
49             this.sortedStrings[right] = tmpToString;
50             left++;
51             right--;
52         }
53     } while (left <= right);
54     
55     if (originalLeft < right)
56         quickSort(originalLeft, right);
57     if (left < originalRight)
58         quickSort(left, originalRight);
59 }
60 /**
61  * Return a new sorted collection from this unsorted collection.
62  * Sort using quick sort.
63  */
64 public void sort(Object JavaDoc[] unSortedObjects, String JavaDoc[] unsortedStrings) {
65     int size = unSortedObjects.length;
66     this.sortedObjects = new Object JavaDoc[size];
67     this.sortedStrings = new String JavaDoc[size];
68     
69     //copy the array so can return a new sorted collection
70 System.arraycopy(unSortedObjects, 0, this.sortedObjects, 0, size);
71     System.arraycopy(unsortedStrings, 0, this.sortedStrings, 0, size);
72     if (size > 1)
73         quickSort(0, size - 1);
74 }
75 }
76
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