Java example source code file (AgeCalculator.java)

This example Java source code file (AgeCalculator.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

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Java - Java tags/keywords

awt, days, event, fieldgroup, fieldset, gridbagconstraints, gui, hours, jpanel, jtextfield, minutes, months, seconds, string, swing, text, weeks, weekyears, years

The AgeCalculator.java Java example source code

/*
 *  Copyright 2001-2005 Stephen Colebourne
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.joda.example.time;

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.Timer;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.Document;

import org.joda.time.Chronology;
import org.joda.time.DateTime;
import org.joda.time.DateTimeZone;
import org.joda.time.DurationField;
import org.joda.time.chrono.ISOChronology;

/**
 * AgeCalculator is a small Swing application that computes age from a specific
 * birthdate and time zone. Age is broken down into multiple fields, which can
 * be independently disabled.
 *
 * @author Brian S O'Neill
 */
public class AgeCalculator extends JFrame {
    static final int
        YEARS = 1,
        MONTHS = 2,
        DAYS = 3,
        WEEKYEARS = 4,
        WEEKS = 5,
        HOURS = 101,
        MINUTES = 102,
        SECONDS = 103;

    public static void main(String[] args) throws Exception {
        new AgeCalculator().show();
    }

    static JComponent fixedSize(JComponent component) {
        component.setMaximumSize(component.getPreferredSize());
        return component;
    }

    static JComponent fixedHeight(JComponent component) {
        Dimension dim = component.getMaximumSize();
        dim.height = component.getPreferredSize().height;
        component.setMaximumSize(dim);
        return component;
    }

    Chronology iChronology;

    private String iBirthdateStr;
    private FieldSet[] iFieldSets;
    private Timer iTimer;

    public AgeCalculator() {
        super();

        iChronology = ISOChronology.getInstance();
        iBirthdateStr = "1970-01-01T00:00:00";

        setTitle("Age Calculator");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        addMainArea(getContentPane());
        addNotify();
        Dimension size = getPreferredSize();
        setSize(size);
        Dimension screenSize = getToolkit().getScreenSize();
        setLocation(screenSize.width / 2 - size.width / 2,
                    screenSize.height / 2 - size.height / 2);

        iTimer = new Timer(500, new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                updateResults();
            }
        });

        iTimer.setInitialDelay(0);
        iTimer.start();
    }

    private void addMainArea(Container container) {
        JPanel panel = new JPanel();
        panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));

        addTopArea(panel);
        panel.add(Box.createVerticalStrut(10));
        addBottomArea(panel);
        panel.add(Box.createVerticalGlue());

        panel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));

        container.add(panel);
    }

    private void addTopArea(Container container) {
        JPanel panel = new JPanel();
        panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS));

        panel.add(fixedHeight(new JLabel("Birthdate")));
        panel.add(Box.createHorizontalStrut(10));

        final JTextField birthdateField = new JTextField(iBirthdateStr + ' ');
        Document doc = birthdateField.getDocument();
        doc.addDocumentListener(new DocumentListener() {
            public void insertUpdate(DocumentEvent e) {
                update(e);
            }
            public void removeUpdate(DocumentEvent e) {
                update(e);
            }
            public void changedUpdate(DocumentEvent e) {
                update(e);
            }
            private void update(DocumentEvent e) {
                iBirthdateStr = birthdateField.getText();
                updateResults();
            }
        });
        panel.add(fixedHeight(birthdateField));

        panel.add(Box.createHorizontalStrut(10));

        Object[] ids = DateTimeZone.getAvailableIDs().toArray();
        final JComboBox zoneSelector = new JComboBox(ids);
        zoneSelector.setSelectedItem(DateTimeZone.getDefault().getID());
        panel.add(fixedSize(zoneSelector));

        zoneSelector.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String id = (String)zoneSelector.getSelectedItem();
                iChronology = ISOChronology.getInstance(DateTimeZone.forID(id));
                updateResults();
            }
        });

        container.add(fixedHeight(panel));
    }

    private void addBottomArea(Container container) {
        JPanel panel = new JPanel();
        panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS));

        ItemListener listener = new ItemListener() {
            public void itemStateChanged(ItemEvent e) {
                updateResults();
            }
        };

        iFieldSets = new FieldSet[] {
            new FieldSet("Month Based", new FieldGroup[] {
                new FieldGroup(listener, "Years", YEARS),
                new FieldGroup(listener, "Months", MONTHS),
                new FieldGroup(listener, "Days", DAYS),
                new FieldGroup(listener, "Hours", HOURS),
                new FieldGroup(listener, "Minutes", MINUTES),
                new FieldGroup(listener, "Seconds", SECONDS)
            })
            ,
            new FieldSet("Week Based", new FieldGroup[] {
                new FieldGroup(listener, "Weekyears", WEEKYEARS),
                new FieldGroup(listener, "Weeks", WEEKS),
                new FieldGroup(listener, "Days", DAYS),
                new FieldGroup(listener, "Hours", HOURS),
                new FieldGroup(listener, "Minutes", MINUTES),
                new FieldGroup(listener, "Seconds", SECONDS)
            })
        };

        for (int i=0; i<iFieldSets.length; i++) {
            if (i > 0) {
                panel.add(Box.createHorizontalStrut(10));
            }
            iFieldSets[i].addTo(panel);
        }
        panel.add(Box.createVerticalGlue());

        container.add(fixedHeight(panel));
    }

    private void updateResults() {
        try {
            DateTime dt = new DateTime(iBirthdateStr.trim(), iChronology);

            long minuend = System.currentTimeMillis();
            long subtrahend = dt.getMillis();

            for (int i=0; i<iFieldSets.length; i++) {
                iFieldSets[i].updateResults(minuend, subtrahend);
            }
        }
        catch (IllegalArgumentException e) {
            for (int i=0; i<iFieldSets.length; i++) {
                iFieldSets[i].setResultsText("");
            }
        }
    }

    private class FieldGroup {
        public final JCheckBox iCheckbox;
        public final JTextField iResult;
        public final int iFieldType;

        FieldGroup(ItemListener listener, String checkboxText, int fieldType) {
            iCheckbox = new JCheckBox(checkboxText, true);
            iCheckbox.addItemListener(listener);
            iResult = new JTextField();
            iResult.setEditable(false);
            iFieldType = fieldType;
        }

        public long updateResult(long minuend, long subtrahend) {
            // Because time zone can be dynamically changed, field must be
            // dynamically acquired.

            DurationField field;
            switch (iFieldType) {
            case YEARS:
                field = iChronology.years();
                break;
            case MONTHS:
                field = iChronology.months();
                break;
            case DAYS:
                field = iChronology.days();
                break;
            case WEEKYEARS:
                field = iChronology.weekyears();
                break;
            case WEEKS:
                field = iChronology.weeks();
                break;
            case HOURS:
                field = iChronology.hours();
                break;
            case MINUTES:
                field = iChronology.minutes();
                break;
            case SECONDS: default:
                field = iChronology.seconds();
                break;
            }

            String textToSet = "";

            if (iCheckbox.isSelected()) {
                long difference = field.getDifferenceAsLong(minuend, subtrahend);
                textToSet = Long.toString(difference);
                subtrahend = field.add(subtrahend, difference);
            }

            if (!iResult.getText().equals(textToSet)) {
                iResult.setText(textToSet);
            }

            return subtrahend;
        }

        public void setResultText(String text) {
            iResult.setText(text);
        }
    }

    private static class FieldSet {
        private final String iTitle;
        private final FieldGroup[] iGroups;

        FieldSet(String title, FieldGroup[] groups) {
            iTitle = title;
            iGroups = groups;
        }

        private long updateResults(long minuend, long subtrahend) {
            for (int i=0; i<iGroups.length; i++) {
                subtrahend = iGroups[i].updateResult(minuend, subtrahend);
            }
            return subtrahend;
        }

        public void setResultsText(String text) {
            for (int i=0; i<iGroups.length; i++) {
                iGroups[i].setResultText(text);
            }
        }

        private void addTo(Container container) {
            JPanel panel = new JPanel();
            GridBagLayout layout = new GridBagLayout();
            panel.setLayout(layout);

            panel.setBorder(BorderFactory.createTitledBorder(iTitle));

            for (int i=0; i<iGroups.length; i++) {
                FieldGroup fg = iGroups[i];
                panel.add(fg.iCheckbox);
                setCheckboxConstraints(layout, fg.iCheckbox, 0, i);
                panel.add(fg.iResult);
                setResultConstraints(layout, fg.iResult, 1, i);
            }

            container.add(fixedHeight(panel));
        }

        private void setCheckboxConstraints(GridBagLayout layout, Component c,
                                            int x, int y)
        {
            GridBagConstraints cons = new GridBagConstraints();
            cons.gridx = x;
            cons.gridy = y;
            cons.weightx = 0.1;
            cons.anchor = GridBagConstraints.WEST;
            layout.setConstraints(c, cons);
        }

        private void setResultConstraints(GridBagLayout layout, Component c,
                                          int x, int y)
        {
            GridBagConstraints cons = new GridBagConstraints();
            cons.gridx = x;
            cons.gridy = y;
            cons.weightx = 1.0;
            cons.anchor = GridBagConstraints.WEST;
            cons.fill = GridBagConstraints.HORIZONTAL;
            layout.setConstraints(c, cons);
        }
    }
}