| /* |
| * Copyright (c) 1999, 2000, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package javax.swing; |
| |
| import java.util.*; |
| |
| /** |
| * The purpose of this class is to help clients support smooth focus |
| * navigation through GUIs with text fields. Such GUIs often need |
| * to ensure that the text entered by the user is valid (for example, |
| * that it's in |
| * the proper format) before allowing the user to navigate out of |
| * the text field. To do this, clients create a subclass of |
| * <code>InputVerifier</code> and, using <code>JComponent</code>'s |
| * <code>setInputVerifier</code> method, |
| * attach an instance of their subclass to the <code>JComponent</code> whose input they |
| * want to validate. Before focus is transfered to another Swing component |
| * that requests it, the input verifier's <code>shouldYieldFocus</code> method is |
| * called. Focus is transfered only if that method returns <code>true</code>. |
| * <p> |
| * The following example has two text fields, with the first one expecting |
| * the string "pass" to be entered by the user. If that string is entered in |
| * the first text field, then the user can advance to the second text field |
| * either by clicking in it or by pressing TAB. However, if another string |
| * is entered in the first text field, then the user will be unable to |
| * transfer focus to the second text field. |
| * <p> |
| * <pre> |
| * import java.awt.*; |
| * import java.util.*; |
| * import java.awt.event.*; |
| * import javax.swing.*; |
| * |
| * // This program demonstrates the use of the Swing InputVerifier class. |
| * // It creates two text fields; the first of the text fields expects the |
| * // string "pass" as input, and will allow focus to advance out of it |
| * // only after that string is typed in by the user. |
| * |
| * public class VerifierTest extends JFrame { |
| * public VerifierTest() { |
| * JTextField tf1 = new JTextField ("Type \"pass\" here"); |
| * getContentPane().add (tf1, BorderLayout.NORTH); |
| * tf1.setInputVerifier(new PassVerifier()); |
| * |
| * JTextField tf2 = new JTextField ("TextField2"); |
| * getContentPane().add (tf2, BorderLayout.SOUTH); |
| * |
| * WindowListener l = new WindowAdapter() { |
| * public void windowClosing(WindowEvent e) { |
| * System.exit(0); |
| * } |
| * }; |
| * addWindowListener(l); |
| * } |
| * |
| * class PassVerifier extends InputVerifier { |
| * public boolean verify(JComponent input) { |
| * JTextField tf = (JTextField) input; |
| * return "pass".equals(tf.getText()); |
| * } |
| * } |
| * |
| * public static void main(String[] args) { |
| * Frame f = new VerifierTest(); |
| * f.pack(); |
| * f.setVisible(true); |
| * } |
| * } |
| * </pre> |
| * |
| * @since 1.3 |
| */ |
| |
| |
| public abstract class InputVerifier { |
| |
| /** |
| * Checks whether the JComponent's input is valid. This method should |
| * have no side effects. It returns a boolean indicating the status |
| * of the argument's input. |
| * |
| * @param input the JComponent to verify |
| * @return <code>true</code> when valid, <code>false</code> when invalid |
| * @see JComponent#setInputVerifier |
| * @see JComponent#getInputVerifier |
| * |
| */ |
| |
| public abstract boolean verify(JComponent input); |
| |
| |
| /** |
| * Calls <code>verify(input)</code> to ensure that the input is valid. |
| * This method can have side effects. In particular, this method |
| * is called when the user attempts to advance focus out of the |
| * argument component into another Swing component in this window. |
| * If this method returns <code>true</code>, then the focus is transfered |
| * normally; if it returns <code>false</code>, then the focus remains in |
| * the argument component. |
| * |
| * @param input the JComponent to verify |
| * @return <code>true</code> when valid, <code>false</code> when invalid |
| * @see JComponent#setInputVerifier |
| * @see JComponent#getInputVerifier |
| * |
| */ |
| |
| public boolean shouldYieldFocus(JComponent input) { |
| return verify(input); |
| } |
| |
| } |