Added support for wiring up a toggle button to a boolean configuration

preference. We love the magic.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@992 6335cc39-0255-0410-8fd6-9bcaacd3b74c

projects/samskivert/src/java/com/samskivert/swing/util/ButtonUtil.java

@@ -1,12 +1,22 @@
 //
-// $Id: ButtonUtil.java,v 1.1 2002/12/04 23:58:22 ray Exp $
+// $Id: ButtonUtil.java,v 1.2 2002/12/14 02:11:24 mdb Exp $
 
 package com.samskivert.swing.util;
 
+import java.beans.PropertyChangeEvent;
+import java.beans.PropertyChangeListener;
+
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
+import java.awt.event.ItemEvent;
+import java.awt.event.ItemListener;
 
 import javax.swing.AbstractButton;
+import javax.swing.JToggleButton;
+import javax.swing.event.AncestorEvent;
+import javax.swing.event.AncestorListener;
+
+import com.samskivert.util.Config;
 
 /**
  * Utilities for buttons.
@@ -32,6 +42,80 @@ public class ButtonUtil
         b.addActionListener(_toggler);
     }
 
+    /**
+     * Binds the supplied button to the named boolean property in the
+     * supplied config repository. When the button is pressed, it will
+     * update the config property and when the config property is changed
+     * (by the button or by other means) it will update the selected state
+     * of the button. When the button is made non-visible, it will be
+     * unbound to the config's property and rebound again if it is once
+     * again visible.
+     */
+    public static void bindToProperty (
+        String property, Config config, AbstractButton button, boolean defval)
+    {
+        // create a config binding which will take care of everything
+        new ButtonConfigBinding(property, config, button, defval);
+    }
+
+    /** Used for {@link #bindToProperty}. */
+    protected static class ButtonConfigBinding
+        implements AncestorListener, PropertyChangeListener, ItemListener
+    {
+        public ButtonConfigBinding (String property, Config config,
+                                    AbstractButton button, boolean defval)
+        {
+            _property = property;
+            _config = config;
+            _button = button;
+            _defval = defval;
+
+            // wire ourselves up to the button
+            button.addAncestorListener(this);
+            button.addItemListener(this);
+
+            // if this is not already a toggle button, we'll need to make
+            // it toggle
+            if (!(button instanceof JToggleButton)) {
+                setToggling(button);
+            }
+        }
+
+        public void ancestorAdded (AncestorEvent event) {
+            // listen for config changes
+            _config.addPropertyChangeListener(_property, this);
+            // set the button up appropriately
+            _button.setSelected(_config.getValue(_property, _defval));
+        }
+
+        public void ancestorRemoved (AncestorEvent event) {
+            // stop listening for config changes
+            _config.removePropertyChangeListener(_property, this);
+        }
+
+        public void ancestorMoved (AncestorEvent event) {
+            // nothing doing
+        }
+
+        public void propertyChange (PropertyChangeEvent event) {
+            // update the button
+            if (event.getPropertyName().equals(_property)) {
+                Boolean value = (Boolean)event.getNewValue();
+                _button.setSelected(value.booleanValue());
+            }
+        }
+
+        public void itemStateChanged (ItemEvent event) {
+            boolean selected = (event.getStateChange() == ItemEvent.SELECTED);
+            _config.setValue(_property, selected);
+        }
+
+        protected String _property;
+        protected Config _config;
+        protected AbstractButton _button;
+        protected boolean _defval;
+    }
+
     /** Our lazily-initialized toggling action listener. */
     protected static ActionListener _toggler;
 }