Java tutorial
/* class DateEntryField * * Copyright (C) 2001 R M Pitman * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package charva.awt.util; import charva.awt.*; import charvax.swing.*; import charva.awt.event.*; import java.util.TimeZone; import java.util.Calendar; import java.util.GregorianCalendar; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * This class displays a date entry field in the format CCYY/MM/DD * and allows the user to edit the contents of the three subfields. * It intercepts each keystroke and causes a beep if a non-numeric key * is typed. */ public class DateEntryField extends JPanel implements KeyListener, FocusListener { private static final Log LOG = LogFactory.getLog(DateEntryField.class); public DateEntryField(Frame owner_) { this(owner_, TimeZone.getDefault()); } public DateEntryField(Frame owner_, TimeZone zone_) { _owner = owner_; init(zone_); } public DateEntryField(Dialog owner_) { this(owner_, TimeZone.getDefault()); } public DateEntryField(Dialog owner_, TimeZone zone_) { _owner = owner_; init(zone_); } private void init(TimeZone zone_) { setLayout(new FlowLayout(FlowLayout.LEFT, 0, 0)); _cal = new GregorianCalendar(zone_); add(_yearField); _yearField.addKeyListener(this); _yearField.addFocusListener(this); add(new JLabel("/")); add(_monthField); _monthField.addKeyListener(this); _monthField.addFocusListener(this); add(new JLabel("/")); add(_dayField); _dayField.addKeyListener(this); _dayField.addFocusListener(this); } public void keyPressed(KeyEvent e_) { /* Allow non-printing keys to be processed by the superclass. */ return; // pass the event on to its destination. } /** * This is never called. */ public void keyReleased(KeyEvent e_) { } public void keyTyped(KeyEvent e_) { int key = e_.getKeyCode(); /* If the key is non-numeric, ring the bell and "consume" the * keystroke so that it doesn't get echoed. */ if (key < '0' || key > '9') { Toolkit.getDefaultToolkit().beep(); e_.consume(); } Component source = (Component) e_.getSource(); if (source == _yearField && _yearField.getText().length() < 4) return; if (source == _monthField && _monthField.getText().length() < 2) return; if (source == _dayField && _dayField.getText().length() < 2) return; Toolkit.getDefaultToolkit().beep(); e_.consume(); } public void focusGained(FocusEvent fe_) { } public void focusLost(FocusEvent e_) { Component source = (Component) e_.getSource(); /* Get the absolute origin of this component. */ Point origin = getLocationOnScreen(); try { if (source == _yearField) { if (_yearField.getText().equals("")) { String[] msgs = { "A valid year must be ", "entered in this field " }; JOptionPane.showMessageDialog(_yearField, msgs, "Error", JOptionPane.ERROR_MESSAGE); _yearField.requestFocus(); } else { int year = Integer.parseInt(_yearField.getText()); _cal.set(Calendar.YEAR, year); } } else if (source == _monthField) { if (_monthField.getText().equals("") == false) { int month = Integer.parseInt(_monthField.getText()); if (month >= 1 && month <= 12) { _cal.clear(Calendar.DAY_OF_MONTH); _cal.set(Calendar.MONTH, month - 1); return; } } String[] msgs = { "The month must be", "between 1 and 12" }; JOptionPane.showMessageDialog(_monthField, msgs, "Error", JOptionPane.ERROR_MESSAGE); _monthField.requestFocus(); } else if (source == _dayField) { int maxday = _cal.getActualMaximum(Calendar.DAY_OF_MONTH); if (_dayField.getText().equals("") == false) { int day = Integer.parseInt(_dayField.getText()); /* By the time we get here, the year and month fields have * been filled in already, so we can check whether the * day is valid. */ if (day >= 1 && day <= maxday) { _cal.set(Calendar.DAY_OF_MONTH, day); return; } } String[] msgs = { "The day must be", "between 1 and " + maxday }; JOptionPane.showMessageDialog(_dayField, msgs, "Error", JOptionPane.ERROR_MESSAGE); _dayField.requestFocus(); } } catch (NumberFormatException e) { // should never happen because we are trapping non-numeric // keystrokes. LOG.warn("Number format exception"); } } /** * Set the fields to the current time. */ public void set() { int year = _cal.get(Calendar.YEAR); _yearField.setText(Integer.toString(year)); int month = _cal.get(Calendar.MONTH) + 1; _monthField.setText(Integer.toString(month)); int day = _cal.get(Calendar.DAY_OF_MONTH); _dayField.setText(Integer.toString(day)); } /** * Set the year field */ public void setYear(int year_) { _yearField.setText(Integer.toString(year_)); _cal.set(Calendar.YEAR, year_); } /** * Set the month field */ public void setMonth(int month_) { _monthField.setText(Integer.toString(month_)); _cal.set(Calendar.MONTH, month_ - 1); } /** */ public void setDay(int day_) { _dayField.setText(Integer.toString(day_)); _cal.set(Calendar.DAY_OF_MONTH, day_); } /** * Get the year value. */ public int getYear() { return Integer.parseInt(_yearField.getText()); } /** * Get the month value (between 1 and 12) */ public int getMonth() { return Integer.parseInt(_monthField.getText()); } /** * Get the day-of-month value. */ public int getDay() { return Integer.parseInt(_dayField.getText()); } private JTextField _yearField = new JTextField(4); private JTextField _monthField = new JTextField(2); private JTextField _dayField = new JTextField(2); private GregorianCalendar _cal; private Window _owner; }