001    /*
002     * Copyright 2002-2004 the original author or authors.
003     * 
004     * Licensed under the Apache License, Version 2.0 (the "License"); you may not
005     * use this file except in compliance with the License. You may obtain a copy of
006     * the License at
007     * 
008     * http://www.apache.org/licenses/LICENSE-2.0
009     * 
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
012     * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
013     * License for the specific language governing permissions and limitations under
014     * the License.
015     */
016    package org.springframework.richclient.table;
017    
018    import java.awt.Point;
019    import java.awt.Rectangle;
020    
021    import javax.swing.JTable;
022    import javax.swing.event.TableModelEvent;
023    import javax.swing.table.TableModel;
024    
025    /**
026     * VisibleTableModelEvent adds the method isVisible to test if the cell
027     * identified by the event is visible.
028     */
029    public class VisibleTableModelEvent extends TableModelEvent {
030        private Point tmpPoint;
031    
032        // This implementation caches the information for one JTable, it is
033        // certainly possible to cache it for more than one should
034        // you have this need.
035        private boolean valid;
036    
037        private int firstVisRow;
038    
039        private int lastVisRow;
040    
041        private int firstVisCol;
042    
043        private int lastVisCol;
044    
045        public VisibleTableModelEvent(TableModel source) {
046            super(source, 0, 0, 0, UPDATE);
047            tmpPoint = new Point();
048        }
049    
050        /**
051         * Resets the underlying fields of the TableModelEvent. This assumes no ONE
052         * is going to cache the TableModelEvent.
053         */
054        public void set(int row, int col) {
055            firstRow = row;
056            lastRow = row;
057            column = col;
058        }
059    
060        /**
061         * Invoked to indicate the visible rows/columns need to be recalculated
062         * again.
063         */
064        public void reset() {
065            valid = false;
066        }
067    
068        public boolean isVisible(JTable table) {
069            if (!valid) {
070                // Determine the visible region of the table.
071                Rectangle visRect = table.getVisibleRect();
072    
073                tmpPoint.x = visRect.x;
074                tmpPoint.y = visRect.y;
075                firstVisCol = table.columnAtPoint(tmpPoint);
076                firstVisRow = table.rowAtPoint(tmpPoint);
077    
078                tmpPoint.x += visRect.width;
079                tmpPoint.y += visRect.height;
080                lastVisCol = table.columnAtPoint(tmpPoint);
081                if (lastVisCol == -1) {
082                    lastVisCol = table.getColumnCount() - 1;
083                }
084                if ((lastVisRow = table.rowAtPoint(tmpPoint)) == -1) {
085                    lastVisRow = table.getRowCount();
086                }
087                valid = true;
088            }
089            return (firstRow >= firstVisRow && firstRow <= lastVisRow && column >= firstVisCol && column <= lastVisCol);
090        }
091    }