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.list;
017    
018    import java.beans.PropertyChangeEvent;
019    import java.beans.PropertyChangeListener;
020    
021    import org.springframework.binding.value.ValueModel;
022    import org.springframework.richclient.core.Guarded;
023    
024    public class SingleListSelectionGuard implements PropertyChangeListener {
025        private ValueModel selectionIndexHolder;
026    
027        private Guarded guarded;
028    
029        public SingleListSelectionGuard(ValueModel selectionIndexHolder, Guarded guarded) {
030            this.selectionIndexHolder = selectionIndexHolder;
031            this.selectionIndexHolder.addValueChangeListener(this);
032            this.guarded = guarded;
033            propertyChange(null);
034        }
035    
036        public void propertyChange(PropertyChangeEvent evt) {
037            Integer value = (Integer)selectionIndexHolder.getValue();
038            if (value == null || value.intValue() == -1) {
039                guarded.setEnabled(false);
040            }
041            else {
042                guarded.setEnabled(true);
043            }
044        }
045    }