/*
* @(#)LayoutComparator.java 1.8 05/11/17
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.swing;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.ListIterator;
import java.awt.Component;
import java.awt.ComponentOrientation;
import java.awt.Window;
/**
* Comparator which attempts to sort Components based on their size and
* position. Code adapted from original javax.swing.DefaultFocusManager
* implementation.
*
* @version 1.8, 11/17/05
* @author David Mendenhall
*/
final class LayoutComparator implements Comparator, java.io.Serializable {
private static final int ROW_TOLERANCE = 10;
private boolean horizontal = true;
private boolean leftToRight = true;
void setComponentOrientation(ComponentOrientation orientation) {
horizontal = orientation.isHorizontal();
leftToRight = orientation.isLeftToRight();
}
public int compare(Object o1, Object o2) {
Component a = (Component)o1;
Component b = (Component)o2;
if (a == b) {
return 0;
}
// Row/Column algorithm only applies to siblings. If 'a' and 'b'
// aren't siblings, then we need to find their most inferior
// ancestors which share a parent. Compute the ancestory lists for
// each Component and then search from the Window down until the
// hierarchy branches.
if (a.getParent() != b.getParent()) {
LinkedList aAncestory, bAncestory;
for(aAncestory = new LinkedList(); a != null; a = a.getParent()) {
aAncestory.add(a);
if (a instanceof Window) {
break;
}
}
if (a == null) {
// 'a' is not part of a Window hierarchy. Can't cope.
throw new ClassCastException();
}
for(bAncestory = new LinkedList(); b != null; b = b.getParent()) {
bAncestory.add(b);
if (b instanceof Window) {
break;
}
}
if (b == null) {
// 'b' is not part of a Window hierarchy. Can't cope.
throw new ClassCastException();
}
for (ListIterator
aIter = aAncestory.listIterator(aAncestory.size()),
bIter = bAncestory.listIterator(bAncestory.size()); ;) {
if (aIter.hasPrevious()) {
a = (Component)aIter.previous();
} else {
// a is an ancestor of b
return -1;
}
if (bIter.hasPrevious()) {
b = (Component)bIter.previous();
} else {
// b is an ancestor of a
return 1;
}
if (a != b) {
break;
}
}
}
int ax = a.getX(), ay = a.getY(), bx = b.getX(), by = b.getY();
int zOrder = a.getParent().getComponentZOrder(a) - b.getParent().getComponentZOrder(b);
if (horizontal) {
if (leftToRight) {
// LT - Western Europe (optional for Japanese, Chinese, Korean)
if (Math.abs(ay - by) < ROW_TOLERANCE) {
return (ax < bx) ? -1 : ((ax > bx) ? 1 : zOrder);
} else {
return (ay < by) ? -1 : 1;
}
} else { // !leftToRight
// RT - Middle East (Arabic, Hebrew)
if (Math.abs(ay - by) < ROW_TOLERANCE) {
return (ax > bx) ? -1 : ((ax < bx) ? 1 : zOrder);
} else {
return (ay < by) ? -1 : 1;
}
}
} else { // !horizontal
if (leftToRight) {
// TL - Mongolian
if (Math.abs(ax - bx) < ROW_TOLERANCE) {
return (ay < by) ? -1 : ((ay > by) ? 1 : zOrder);
} else {
return (ax < bx) ? -1 : 1;
}
} else { // !leftToRight
// TR - Japanese, Chinese, Korean
if (Math.abs(ax - bx) < ROW_TOLERANCE) {
return (ay < by) ? -1 : ((ay > by) ? 1 : zOrder);
} else {
return (ax > bx) ? -1 : 1;
}
}
}
}
}