Java tutorial
/* * Copyright (c) 1995 - 2008 Sun Microsystems, Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of Sun Microsystems nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* * TextAreaDemo.java requires no other files. */ import java.awt.event.ActionEvent; import java.util.ArrayList; import java.util.Collections; import java.util.List; import javax.swing.AbstractAction; import javax.swing.ActionMap; import javax.swing.GroupLayout; import javax.swing.InputMap; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JScrollPane; import javax.swing.JTextArea; import javax.swing.KeyStroke; import javax.swing.LayoutStyle; import javax.swing.SwingUtilities; import javax.swing.UIManager; import javax.swing.WindowConstants; import javax.swing.GroupLayout.Alignment; import javax.swing.GroupLayout.ParallelGroup; import javax.swing.GroupLayout.SequentialGroup; import javax.swing.event.DocumentEvent; import javax.swing.event.DocumentListener; import javax.swing.text.BadLocationException; public class TextAreaDemo extends JFrame implements DocumentListener { private JLabel jLabel1; private JScrollPane jScrollPane1; private JTextArea textArea; private static final String COMMIT_ACTION = "commit"; private static enum Mode { INSERT, COMPLETION }; private final List<String> words; private Mode mode = Mode.INSERT; public TextAreaDemo() { super("TextAreaDemo"); initComponents(); textArea.getDocument().addDocumentListener(this); InputMap im = textArea.getInputMap(); ActionMap am = textArea.getActionMap(); im.put(KeyStroke.getKeyStroke("ENTER"), COMMIT_ACTION); am.put(COMMIT_ACTION, new CommitAction()); words = new ArrayList<String>(5); words.add("spark"); words.add("special"); words.add("spectacles"); words.add("spectacular"); words.add("swing"); } private void initComponents() { jLabel1 = new JLabel("Try typing 'spectacular' or 'Swing'..."); textArea = new JTextArea(); setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); textArea.setColumns(20); textArea.setLineWrap(true); textArea.setRows(5); textArea.setWrapStyleWord(true); jScrollPane1 = new JScrollPane(textArea); GroupLayout layout = new GroupLayout(getContentPane()); getContentPane().setLayout(layout); // Create a parallel group for the horizontal axis ParallelGroup hGroup = layout.createParallelGroup(GroupLayout.Alignment.LEADING); // Create a sequential and a parallel groups SequentialGroup h1 = layout.createSequentialGroup(); ParallelGroup h2 = layout.createParallelGroup(GroupLayout.Alignment.TRAILING); // Add a scroll panel and a label to the parallel group h2 h2.addComponent(jScrollPane1, GroupLayout.Alignment.LEADING, GroupLayout.DEFAULT_SIZE, 212, Short.MAX_VALUE); h2.addComponent(jLabel1, GroupLayout.Alignment.LEADING, GroupLayout.DEFAULT_SIZE, 212, Short.MAX_VALUE); // Add a container gap to the sequential group h1 h1.addContainerGap(); // Add the group h2 to the group h1 h1.addGroup(h2); h1.addContainerGap(); // Add the group h1 to hGroup hGroup.addGroup(Alignment.TRAILING, h1); // Create the horizontal group layout.setHorizontalGroup(hGroup); // Create a parallel group for the vertical axis ParallelGroup vGroup = layout.createParallelGroup(GroupLayout.Alignment.LEADING); // Create a sequential group SequentialGroup v1 = layout.createSequentialGroup(); // Add a container gap to the sequential group v1 v1.addContainerGap(); // Add a label to the sequential group v1 v1.addComponent(jLabel1); v1.addPreferredGap(LayoutStyle.ComponentPlacement.RELATED); // Add scroll panel to the sequential group v1 v1.addComponent(jScrollPane1, GroupLayout.DEFAULT_SIZE, 100, Short.MAX_VALUE); v1.addContainerGap(); // Add the group v1 to vGroup vGroup.addGroup(v1); // Create the vertical group layout.setVerticalGroup(vGroup); pack(); } // Listener methods public void changedUpdate(DocumentEvent ev) { } public void removeUpdate(DocumentEvent ev) { } public void insertUpdate(DocumentEvent ev) { if (ev.getLength() != 1) { return; } int pos = ev.getOffset(); String content = null; try { content = textArea.getText(0, pos + 1); } catch (BadLocationException e) { e.printStackTrace(); } // Find where the word starts int w; for (w = pos; w >= 0; w--) { if (!Character.isLetter(content.charAt(w))) { break; } } if (pos - w < 2) { // Too few chars return; } String prefix = content.substring(w + 1).toLowerCase(); int n = Collections.binarySearch(words, prefix); if (n < 0 && -n <= words.size()) { String match = words.get(-n - 1); if (match.startsWith(prefix)) { // A completion is found String completion = match.substring(pos - w); // We cannot modify Document from within notification, // so we submit a task that does the change later SwingUtilities.invokeLater(new CompletionTask(completion, pos + 1)); } } else { // Nothing found mode = Mode.INSERT; } } private class CompletionTask implements Runnable { String completion; int position; CompletionTask(String completion, int position) { this.completion = completion; this.position = position; } public void run() { textArea.insert(completion, position); textArea.setCaretPosition(position + completion.length()); textArea.moveCaretPosition(position); mode = Mode.COMPLETION; } } private class CommitAction extends AbstractAction { public void actionPerformed(ActionEvent ev) { if (mode == Mode.COMPLETION) { int pos = textArea.getSelectionEnd(); textArea.insert(" ", pos); textArea.setCaretPosition(pos + 1); mode = Mode.INSERT; } else { textArea.replaceSelection("\n"); } } } public static void main(String args[]) { SwingUtilities.invokeLater(new Runnable() { public void run() { // Turn off metal's use of bold fonts UIManager.put("swing.boldMetal", Boolean.FALSE); new TextAreaDemo().setVisible(true); } }); } }