gecko-dev/grendel/view/Sorter.java
1998-09-09 00:52:38 +00:00

102 lines
3.0 KiB
Java

/* -*- Mode: java; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.0 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* The Original Code is the Grendel mail/news client.
*
* The Initial Developer of the Original Code is Netscape Communications
* Corporation. Portions created by Netscape are Copyright (C) 1997
* Netscape Communications Corporation. All Rights Reserved.
*
* Created: Jamie Zawinski <jwz@netscape.com>, 13 Jun 1995.
* Ported from C on 14 Aug 1997.
*/
package grendel.view;
import java.util.Vector;
import java.util.Enumeration;
import calypso.util.QSort;
import calypso.util.Comparer;
/**
This sorts a set of messages by some metric.
The set of messages may already be arranged into a thread hierarchy; in
that case, siblings are sorted while leaving parent/child relationships
intact. The sets of messages are accessed via the ISortable interface.
@see ISortable
@see Threader
@see Comparer
@see QSort
*/
class Sorter {
private Vector v = null;
private QSort sorter = null;
/** Creates an object for sorting messages.
Use the sortMessageChildren() method to sort them.
@param comparer The object which compares two ISortable objects
for ordering.
*/
public Sorter(Comparer comparer) {
this.sorter = new QSort(comparer);
v = new Vector(100);
}
/** Sorts the set of messages indicated by sortable_root.
The child-list of sortable_root will be modified (reordered)
upon completion (as will all grandchildren.)
@param sortable_root The root object; it should have
children, but no siblings.
*/
public void sortMessageChildren(ISortable sortable_root) {
sortMessageChildren_1(sortable_root);
sorter = null;
v.setSize(0);
v.trimToSize();
v = null;
}
private void sortMessageChildren_1(ISortable parent) {
int count = 0;
// Populate v with the kids.
for (Enumeration e = parent.children();
e != null && e.hasMoreElements();) {
v.addElement((ISortable) e.nextElement());
count++;
}
// Copy v to a, growing a if necessary.
ISortable a[] = new ISortable[count+1];
v.copyInto(a);
v.setSize(0);
// Sort a.
sorter.sort(a, 0, count);
// Flush new order of a into the ISortables.
parent.setChild(a[0]);
a[count] = null;
for (int i = 0; i < count; i++)
a[i].setNext(a[i+1]);
// Repeat on the grandchildren.
for (int i = 0; i < count; i++)
sortMessageChildren_1(a[i]);
a = null;
}
}