Hi, this patch adds a new Demo to the Swing Activity board: It shows how to use the DocumentFilter class. Please try it out and guess where you have seen the demonstrated behavior before. :)
Although you will notice that everything works fine, our current implementation
of JTextComponent (and most likely some of the related classes that deal with
the Document class) can fail very easily with it: When text is inserted, such
code usually computes the new cursor location by using the length of the
inserted text. What this code is totally unaware of, is that a DocumentFilter
may change what is inserted into the document. In certain situations the caret
is then placed behind the document's end and an exception occurs. I will file a
PR about this later.
Anyway, here is the ChangeLog:
2006-04-18 Robert Schuster <[EMAIL PROTECTED]>
* examples/gnu/classpath/examples/swing/DocumentFilterDemo.java:
New file.
* examples/gnu/classpath/examples/swing/Demo.java:
(mkMenuBar): Added DocumenFilter demo.
cya
Robert
Index: examples/gnu/classpath/examples/swing/Demo.java
===================================================================
RCS file: /cvsroot/classpath/classpath/examples/gnu/classpath/examples/swing/Demo.java,v
retrieving revision 1.43
diff -u -r1.43 Demo.java
--- examples/gnu/classpath/examples/swing/Demo.java 13 Apr 2006 16:08:10 -0000 1.43
+++ examples/gnu/classpath/examples/swing/Demo.java 18 Apr 2006 19:34:03 -0000
@@ -151,6 +151,9 @@
examples.add(new JMenuItem(new PopupAction("Theme Editor",
MetalThemeEditor.createDemoFactory())));
+ examples.add(new JMenuItem(new PopupAction("DocumentFilter",
+ DocumentFilterDemo.createDemoFactory())));
+
final JMenuItem vmMenu;
help.add(new JMenuItem("just play with the widgets"));
Index: examples/gnu/classpath/examples/swing/DocumentFilterDemo.java
===================================================================
RCS file: examples/gnu/classpath/examples/swing/DocumentFilterDemo.java
diff -N examples/gnu/classpath/examples/swing/DocumentFilterDemo.java
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ examples/gnu/classpath/examples/swing/DocumentFilterDemo.java 18 Apr 2006 19:34:03 -0000
@@ -0,0 +1,289 @@
+/* DpocumentFilterDemo.java -- An example for the DocumentFilter class.
+ Copyright (C) 2006 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath examples.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+*/
+
+
+package gnu.classpath.examples.swing;
+
+import java.awt.BorderLayout;
+import java.awt.Color;
+import java.awt.GridLayout;
+import java.awt.Toolkit;
+import java.awt.datatransfer.Clipboard;
+import java.awt.datatransfer.StringSelection;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+import javax.swing.JButton;
+import javax.swing.JComboBox;
+import javax.swing.JComponent;
+import javax.swing.JFrame;
+import javax.swing.JLabel;
+import javax.swing.JOptionPane;
+import javax.swing.JPanel;
+import javax.swing.JTextField;
+import javax.swing.SwingUtilities;
+import javax.swing.text.AbstractDocument;
+import javax.swing.text.AttributeSet;
+import javax.swing.text.BadLocationException;
+import javax.swing.text.DocumentFilter;
+import javax.swing.text.TextAction;
+
+/**
+ * A demonstration of the <code>javax.swing.text.DocumentFilter</code> class.
+ *
+ * <p>Similar to a dialog in a popular programming IDE the user can insert
+ * a CVS URL into a textfield and the filter will split the components apart
+ * and will put them into the right textfields saving the user a lot of
+ * typing time.</p>
+ *
+ * @author Robert Schuster
+ */
+public class DocumentFilterDemo
+ extends JPanel
+ implements ActionListener
+{
+ JTextField target;
+
+ JTextField host;
+ JTextField repositoryPath;
+ JTextField user;
+ JTextField password;
+ JComboBox connectionType;
+
+ /**
+ * Creates a new demo instance.
+ */
+ public DocumentFilterDemo()
+ {
+ createContent();
+ // initFrameContent() is only called (from main) when running this app
+ // standalone
+ }
+
+ /**
+ * When the demo is run independently, the frame is displayed, so we should
+ * initialise the content panel (including the demo content and a close
+ * button). But when the demo is run as part of the Swing activity board,
+ * only the demo content panel is used, the frame itself is never displayed,
+ * so we can avoid this step.
+ */
+ void initFrameContent()
+ {
+ JPanel closePanel = new JPanel();
+ JButton closeButton = new JButton("Close");
+ closeButton.setActionCommand("CLOSE");
+ closeButton.addActionListener(this);
+ closePanel.add(closeButton);
+ add(closePanel, BorderLayout.SOUTH);
+ }
+
+ private void createContent()
+ {
+ setLayout(new BorderLayout());
+
+ JPanel panel = new JPanel(new GridLayout(7, 2));
+ panel.add(new JLabel("CVS URL:"));
+ panel.add(target = new JTextField(20));
+ target.setBackground(Color.RED);
+
+ panel.add(new JLabel("Host:"));
+ panel.add(host = new JTextField(20));
+
+ panel.add(new JLabel("Repository Path:"));
+ panel.add(repositoryPath = new JTextField(20));
+
+ panel.add(new JLabel("Username:"));
+ panel.add(user = new JTextField(20));
+
+ panel.add(new JLabel("Password:"));
+ panel.add(password = new JTextField(20));
+
+ panel.add(new JLabel("Connection Type:"));
+ panel.add(connectionType = new JComboBox());
+
+ JButton helpButton = new JButton("Help");
+ panel.add(helpButton);
+
+ helpButton.addActionListener(new ActionListener()
+ {
+ public void actionPerformed(ActionEvent ae)
+ {
+ JOptionPane.showMessageDialog(DocumentFilterDemo.this,
+ "Paste a CVS URL into the red " +
+ "textfield.\nIf you do not want to " +
+ "look up a CVS URL yourself click " +
+ "on the 'provide me an example' " +
+ "button.\nThis will paste a proper " +
+ "string into your clipboard.");
+ }
+ });
+
+ JButton exampleButton = new JButton("Provide me an example!");
+ panel.add(exampleButton);
+ exampleButton.addActionListener(new ActionListener()
+ {
+ public void actionPerformed(ActionEvent ae)
+ {
+ try
+ {
+ Toolkit tk = Toolkit.getDefaultToolkit();
+ Clipboard cb = tk.getSystemSelection();
+ StringSelection selection
+ = new StringSelection(":extssh:[EMAIL PROTECTED]:" +
+ "/cvs/example/project");
+
+ cb.setContents(selection, selection);
+
+ // Confirm success with a beep.
+ tk.beep();
+ }
+ catch (IllegalStateException ise)
+ {
+ JOptionPane.showMessageDialog(DocumentFilterDemo.this,
+ "Clipboard is currently" +
+ " unavailable.",
+ "Error",
+ JOptionPane.ERROR_MESSAGE);
+ }
+ }
+ });
+
+ connectionType.addItem("pserver");
+ connectionType.addItem("ext");
+ connectionType.addItem("extssh");
+
+ add(panel);
+
+ AbstractDocument doc = (AbstractDocument) target.getDocument();
+ doc.setDocumentFilter(new CVSFilter());
+ }
+
+ public void actionPerformed(ActionEvent e)
+ {
+ if (e.getActionCommand().equals("CLOSE"))
+ System.exit(0);
+
+ }
+
+ public static void main(String[] args)
+ {
+ SwingUtilities.invokeLater
+ (new Runnable()
+ {
+ public void run()
+ {
+ DocumentFilterDemo app = new DocumentFilterDemo();
+ app.initFrameContent();
+ JFrame frame = new JFrame("DocumentFilterDemo");
+ frame.getContentPane().add(app);
+ frame.pack();
+ frame.setVisible(true);
+ frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+ }
+ });
+ }
+
+ /**
+ * Returns a DemoFactory that creates a DocumentFilterDemo.
+ *
+ * @return a DemoFactory that creates a DocumentFilterDemo
+ */
+ public static DemoFactory createDemoFactory()
+ {
+ return new DemoFactory()
+ {
+ public JComponent createDemo()
+ {
+ return new DocumentFilterDemo();
+ }
+ };
+ }
+
+ class CVSFilter extends DocumentFilter
+ {
+ // example: pserver:[EMAIL PROTECTED]:/cvsroot/fmj
+ String cvsPattern = ":?(pserver|ext|extssh):(\\w)+(:(\\w)+)?@(\\w|\\.)+:/(\\w|/)*";
+
+ public void insertString(DocumentFilter.FilterBypass fb,
+ int offset, String string,
+ AttributeSet attr)
+ throws BadLocationException
+ {
+ filterString(fb, offset, 0, string, attr, true);
+ }
+
+ public void replace(DocumentFilter.FilterBypass fb,
+ int offset, int length,
+ String string,
+ AttributeSet attr)
+ throws BadLocationException
+ {
+ filterString(fb, offset, length, string, attr, false);
+ }
+
+ public void filterString(DocumentFilter.FilterBypass fb,
+ int offset, int length, String string,
+ AttributeSet attr, boolean insertion)
+ throws BadLocationException
+ {
+ if(string.matches(cvsPattern))
+ {
+ // Split off the connection type part.
+ String[] result = string.split(":", 2);
+
+ // If the string contained a leading colon, result[0]
+ // will be empty at that point. We simply repeat the split
+ // operation on the remaining string and continue.
+ if(result[0].equals(""))
+ result = result[1].split(":", 2);
+
+ connectionType.setSelectedItem(result[0]);
+
+ // Split off the username and password part
+ result = result[1].split("@", 2);
+
+ // Break username and password in half
+ String[] userCredentials = result[0].split(":");
+ user.setText(userCredentials[0]);
+
+ // If the result has two entries the second one will
+ // be the password.
+ if (userCredentials.length == 2)
+ password.setText(userCredentials[1]);
+
+ // Now break the host part apart.
+ result = result[1].split(":");
+
+ host.setText(result[0]);
+
+ repositoryPath.setText(result[1]);
+ }
+
+ // The unmodified string is put into the document.
+ if (insertion)
+ fb.insertString(offset, string, attr);
+ else
+ fb.replace(offset, length, string, attr);
+ }
+
+ }
+
+}
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