Home » openjdk-7 » javax » swing » [javadoc | source]

    1   /*
    2    * Copyright (c) 2000, 2008, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   16    *
   17    * You should have received a copy of the GNU General Public License version
   18    * 2 along with this work; if not, write to the Free Software Foundation,
   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
   21    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22    * or visit www.oracle.com if you need additional information or have any
   23    * questions.
   24    */
   25   package javax.swing;
   26   
   27   import java.util.Comparator;
   28   import java.util.LinkedList;
   29   import java.util.ListIterator;
   30   import java.awt.Component;
   31   import java.awt.ComponentOrientation;
   32   import java.awt.Window;
   33   
   34   
   35   /**
   36    * Comparator which attempts to sort Components based on their size and
   37    * position. Code adapted from original javax.swing.DefaultFocusManager
   38    * implementation.
   39    *
   40    * @author David Mendenhall
   41    */
   42   final class LayoutComparator implements Comparator<Component>, java.io.Serializable {
   43   
   44       private static final int ROW_TOLERANCE = 10;
   45   
   46       private boolean horizontal = true;
   47       private boolean leftToRight = true;
   48   
   49       void setComponentOrientation(ComponentOrientation orientation) {
   50           horizontal = orientation.isHorizontal();
   51           leftToRight = orientation.isLeftToRight();
   52       }
   53   
   54       public int compare(Component a, Component b) {
   55           if (a == b) {
   56               return 0;
   57           }
   58   
   59           // Row/Column algorithm only applies to siblings. If 'a' and 'b'
   60           // aren't siblings, then we need to find their most inferior
   61           // ancestors which share a parent. Compute the ancestory lists for
   62           // each Component and then search from the Window down until the
   63           // hierarchy branches.
   64           if (a.getParent() != b.getParent()) {
   65               LinkedList<Component> aAncestory = new LinkedList<Component>();
   66   
   67               for(; a != null; a = a.getParent()) {
   68                   aAncestory.add(a);
   69                   if (a instanceof Window) {
   70                       break;
   71                   }
   72               }
   73               if (a == null) {
   74                   // 'a' is not part of a Window hierarchy. Can't cope.
   75                   throw new ClassCastException();
   76               }
   77   
   78               LinkedList<Component> bAncestory = new LinkedList<Component>();
   79   
   80               for(; b != null; b = b.getParent()) {
   81                   bAncestory.add(b);
   82                   if (b instanceof Window) {
   83                       break;
   84                   }
   85               }
   86               if (b == null) {
   87                   // 'b' is not part of a Window hierarchy. Can't cope.
   88                   throw new ClassCastException();
   89               }
   90   
   91               for (ListIterator<Component>
   92                        aIter = aAncestory.listIterator(aAncestory.size()),
   93                        bIter = bAncestory.listIterator(bAncestory.size()); ;) {
   94                   if (aIter.hasPrevious()) {
   95                       a = aIter.previous();
   96                   } else {
   97                       // a is an ancestor of b
   98                       return -1;
   99                   }
  100   
  101                   if (bIter.hasPrevious()) {
  102                       b = bIter.previous();
  103                   } else {
  104                       // b is an ancestor of a
  105                       return 1;
  106                   }
  107   
  108                   if (a != b) {
  109                       break;
  110                   }
  111               }
  112           }
  113   
  114           int ax = a.getX(), ay = a.getY(), bx = b.getX(), by = b.getY();
  115   
  116           int zOrder = a.getParent().getComponentZOrder(a) - b.getParent().getComponentZOrder(b);
  117           if (horizontal) {
  118               if (leftToRight) {
  119   
  120                   // LT - Western Europe (optional for Japanese, Chinese, Korean)
  121   
  122                   if (Math.abs(ay - by) < ROW_TOLERANCE) {
  123                       return (ax < bx) ? -1 : ((ax > bx) ? 1 : zOrder);
  124                   } else {
  125                       return (ay < by) ? -1 : 1;
  126                   }
  127               } else { // !leftToRight
  128   
  129                   // RT - Middle East (Arabic, Hebrew)
  130   
  131                   if (Math.abs(ay - by) < ROW_TOLERANCE) {
  132                       return (ax > bx) ? -1 : ((ax < bx) ? 1 : zOrder);
  133                   } else {
  134                       return (ay < by) ? -1 : 1;
  135                   }
  136               }
  137           } else { // !horizontal
  138               if (leftToRight) {
  139   
  140                   // TL - Mongolian
  141   
  142                   if (Math.abs(ax - bx) < ROW_TOLERANCE) {
  143                       return (ay < by) ? -1 : ((ay > by) ? 1 : zOrder);
  144                   } else {
  145                       return (ax < bx) ? -1 : 1;
  146                   }
  147               } else { // !leftToRight
  148   
  149                   // TR - Japanese, Chinese, Korean
  150   
  151                   if (Math.abs(ax - bx) < ROW_TOLERANCE) {
  152                       return (ay < by) ? -1 : ((ay > by) ? 1 : zOrder);
  153                   } else {
  154                       return (ax > bx) ? -1 : 1;
  155                   }
  156               }
  157           }
  158       }
  159   }

Home » openjdk-7 » javax » swing » [javadoc | source]