INTEGRATION: CWS sdk02 (1.1.2); FILE ADDED

2003/05/21 16:14:45 af 1.1.2.2: #109790# Adaption to recent UAA changes.
2003/05/09 10:31:15 jsc 1.1.2.1: #109045# insert new and remove example zip file

odk/examples/DevelopersGuide/Accessibility/MessageArea.java

+import java.awt.Font;
+import java.awt.Rectangle;
+import java.awt.Color;
+import java.awt.Graphics;
+import javax.swing.JScrollPane;
+import javax.swing.JTextArea;
+import javax.swing.JScrollBar;
+
+
+
+/** A message area displays text in a scrollable text widget.  It is a
+    singleton.  Other objects can access it directly to display messages.
+*/
+public class MessageArea
+    extends JScrollPane
+{
+    public static synchronized MessageArea Instance ()
+    {
+        if (saInstance == null)
+            saInstance = new MessageArea ();
+        return saInstance;
+    }
+
+
+
+
+    /** Create a new message area.  This method is private because the class is
+        a singleton and may therefore not be instanciated from the outside.
+    */
+    private MessageArea ()
+    {
+        maText = new JTextArea();
+        maText.setBackground (new Color (255,250,240));
+        maText.setFont (new Font ("Helvetica", Font.PLAIN, 9));
+        setViewportView (maText);
+        setVerticalScrollBarPolicy (JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
+        setHorizontalScrollBarPolicy (JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
+
+        printMessage (
+            "class path is " + System.getProperty ("java.class.path") + "\n");
+    }
+
+
+
+
+    /** Show the given string at the end of the message area and scroll to make
+        it visible.
+    */
+    public static synchronized void print (String aMessage)
+    {
+        Instance().printMessage(aMessage);
+    }
+
+
+
+
+    /** Show the given string at the end of the message area and scroll to make
+        it visible.
+    */
+    public static void println (String aMessage)
+    {
+        Instance().printMessage (aMessage+"\n");
+    }
+
+
+    public void paintComponent (Graphics g)
+    {
+        // Synchronize with the graphics object to prevent paint problems.
+        // Remember that this is not done by Swing itself.
+        synchronized (g)
+        {
+            JScrollBar sb = getVerticalScrollBar();
+            if (sb != null)
+            {
+                int nScrollBarValue = sb.getMaximum() - sb.getVisibleAmount() - 1;
+                sb.setValue (nScrollBarValue);
+            }
+            super.paintComponent (g);
+        }
+    }
+
+
+
+
+    /** Append the given string to the end of the text and scroll so that it
+        becomes visible.  This is an internal method.  Use one of the static
+        and public ones.
+    */
+    private synchronized void printMessage (String aMessage)
+    {
+        maText.append (aMessage);
+    }
+
+
+
+
+    private static MessageArea saInstance = null;
+    private JTextArea maText;
+}