button utilities

git-svn-id: https://samskivert.googlecode.com/svn/trunk@960 6335cc39-0255-0410-8fd6-9bcaacd3b74c

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

@@ -0,0 +1,37 @@
+//
+// $Id: ButtonUtil.java,v 1.1 2002/12/04 23:58:22 ray Exp $
+
+package com.samskivert.swing.util;
+
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+import javax.swing.AbstractButton;
+
+/**
+ * Utilities for buttons.
+ */
+public class ButtonUtil
+{
+    /**
+     * Set the specified button such that it alternates between being
+     * selected and not whenever it is pushed.
+     */
+    public static synchronized void setToggling (AbstractButton b)
+    {
+        if (_toggler == null) {
+            _toggler = new ActionListener () {
+                public void actionPerformed (ActionEvent event)
+                {
+                    AbstractButton but = (AbstractButton) event.getSource();
+                    but.setSelected(!but.isSelected());
+                }
+            };
+        }
+
+        b.addActionListener(_toggler);
+    }
+
+    /** Our lazily-initialized toggling action listener. */
+    protected static ActionListener _toggler;
+}