inputverificationdialogdemo.java

java tutorial.sun公司官方出品。java入门书籍。最新版

/*
 * 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.
 */ 

/*
 * InputVerificationDialogDemo.java requires no other files.
 */
package misc;

import java.util.Set;
import java.util.HashSet;

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;

import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeEvent;

import java.text.*;

/**
 * InputVerificationDialogDemo.java is a 1.4 example that
 * requires no other files.
 *
 * Yet another mortgage calculator.
 * However, instead of using a formatted text field,
 * as shown in FormattedTextFieldDemo, this example
 * uses input verification to validate user input.
 * This one uses a dialog to warn people when their input is bad.
 */
public class InputVerificationDialogDemo extends JPanel {
    //Default values
    private static double DEFAULT_AMOUNT = 100000;
    private static double DEFAULT_RATE = 7.5;  //7.5 %
    private static int DEFAULT_PERIOD = 30;

    //Labels to identify the text fields
    private JLabel amountLabel;
    private JLabel rateLabel;
    private JLabel numPeriodsLabel;
    private JLabel paymentLabel;

    //Strings for the labels
    private static String amountString = "Loan Amount (10,000 - 10,000,000): ";
    private static String rateString = "APR (>= 0%): ";
    private static String numPeriodsString = "Years (1-40): ";
    private static String paymentString = "Monthly Payment: ";

    //Text fields for data entry
    private JTextField amountField;
    private JTextField rateField;
    private JTextField numPeriodsField;
    private JTextField paymentField;

    //Formats to format and parse numbers
    private NumberFormat moneyFormat;
    private NumberFormat percentFormat;
    private DecimalFormat decimalFormat;
    private DecimalFormat paymentFormat;
    private NumberFormat integerFormat;
    private MyVerifier verifier = new MyVerifier();

    public InputVerificationDialogDemo() {
        super(new BorderLayout());
        setUpFormats();
        double payment = computePayment(DEFAULT_AMOUNT,
                                        DEFAULT_RATE,
                                        DEFAULT_PERIOD);

        //Create the labels.
        amountLabel = new JLabel(amountString);
        rateLabel = new JLabel(rateString);
        numPeriodsLabel = new JLabel(numPeriodsString);
        paymentLabel = new JLabel(paymentString);

        //Create the text fields and set them up.
        amountField = new JTextField(moneyFormat.format(DEFAULT_AMOUNT), 10);
        amountField.setInputVerifier(verifier);

        rateField = new JTextField(percentFormat.format(DEFAULT_RATE), 10);
        rateField.setInputVerifier(verifier);

        numPeriodsField = new JTextField(decimalFormat.format(DEFAULT_PERIOD), 10);
        numPeriodsField.setInputVerifier(verifier);

        paymentField = new JTextField(paymentFormat.format(payment), 10);
        paymentField.setInputVerifier(verifier);
        paymentField.setEditable(false);
        //Remove this component from the focus cycle.
        paymentField.setFocusable(false); 
        paymentField.setForeground(Color.red);

        //Register an action listener to handle Return.
        amountField.addActionListener(verifier);
        rateField.addActionListener(verifier);
        numPeriodsField.addActionListener(verifier);

        //Tell accessibility tools about label/textfield pairs.
        amountLabel.setLabelFor(amountField);
        rateLabel.setLabelFor(rateField);
        numPeriodsLabel.setLabelFor(numPeriodsField);
        paymentLabel.setLabelFor(paymentField);

        //Lay out the labels in a panel.
        JPanel labelPane = new JPanel(new GridLayout(0,1));
        labelPane.add(amountLabel);
        labelPane.add(rateLabel);
        labelPane.add(numPeriodsLabel);
        labelPane.add(paymentLabel);

        //Layout the text fields in a panel.
        JPanel fieldPane = new JPanel(new GridLayout(0,1));
        fieldPane.add(amountField);
        fieldPane.add(rateField);
        fieldPane.add(numPeriodsField);
        fieldPane.add(paymentField);

        //Put the panels in this panel, labels on left,
        //text fields on right.
        setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
        add(labelPane, BorderLayout.CENTER);
        add(fieldPane, BorderLayout.LINE_END);
    }

    class MyVerifier extends InputVerifier 
                     implements ActionListener {
        double MIN_AMOUNT = 10000.0;
        double MAX_AMOUNT = 10000000.0;
        double MIN_RATE = 0.0;
        int MIN_PERIOD = 1;
        int MAX_PERIOD = 40;
        String message = null;

        public boolean shouldYieldFocus(JComponent input) {
            boolean inputOK = verify(input);
            makeItPretty(input);
            updatePayment();

            if (inputOK) {
                return true;
            }


            //Pop up the message dialog.
            message += ".\nPlease try again.";
            JOptionPane.showMessageDialog(null, //no owner frame
                                          message, //text to display
                                          "Invalid Value", //title
                                          JOptionPane.WARNING_MESSAGE);

            //Reinstall the input verifier.
            input.setInputVerifier(this);

            //Beep and then tell whoever called us that we don't
            //want to yield focus.
            Toolkit.getDefaultToolkit().beep();
            return false;
        }

        protected void updatePayment() {
            double amount = DEFAULT_AMOUNT;
            double rate = DEFAULT_RATE;
            int numPeriods = DEFAULT_PERIOD;
            double payment = 0.0;

            //Parse the values.
            try {
                amount = moneyFormat.parse(amountField.getText()).
                                 doubleValue();
            } catch (ParseException pe) {}
            try {
                rate = percentFormat.parse(rateField.getText()).
                                 doubleValue();
            } catch (ParseException pe) {}
            try {
                numPeriods = decimalFormat.parse(numPeriodsField.getText()).
                    intValue();
            } catch (ParseException pe) {}

            //Calculate the result and update the GUI.
            payment = computePayment(amount, rate, numPeriods);
            paymentField.setText(paymentFormat.format(payment));
        }

        //This method checks input, but should cause no side effects.
        public boolean verify(JComponent input) {
            return checkField(input, false);