src/java.desktop/share/classes/javax/swing/text/DateFormatter.java

/*
 * Copyright (c) 2000, 2020, 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.text;

import java.awt.event.*;
import java.text.*;
import java.util.*;
import javax.swing.*;
import javax.swing.text.*;

/**
 * DateFormatter is an <code>InternationalFormatter</code> that does its
 * formatting by way of an instance of <code>java.text.DateFormat</code>.
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases. The current serialization support is
 * appropriate for short term storage or RMI between applications running
 * the same version of Swing.  As of 1.4, support for long term storage
 * of all JavaBeans
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @see java.text.DateFormat
 *
 * @since 1.4
 */
@SuppressWarnings("serial") // Same-version serialization only
public class DateFormatter extends InternationalFormatter {
    /**
     * This is shorthand for
     * <code>new DateFormatter(DateFormat.getDateInstance())</code>.
     */
    public DateFormatter() {
        this(DateFormat.getDateInstance());
    }

    /**
     * Returns a DateFormatter configured with the specified
     * <code>Format</code> instance.
     *
     * @param format Format used to dictate legal values
     */
    public DateFormatter(DateFormat format) {
        super(format);
        setFormat(format);
    }

    /**
     * Sets the format that dictates the legal values that can be edited
     * and displayed.
     * <p>
     * If you have used the nullary constructor the value of this property
     * will be determined for the current locale by way of the
     * <code>Dateformat.getDateInstance()</code> method.
     *
     * @param format DateFormat instance used for converting from/to Strings
     */
    public void setFormat(DateFormat format) {
        super.setFormat(format);
    }

    /**
     * Returns the Calendar that <code>DateFormat</code> is associated with,
     * or if the <code>Format</code> is not a <code>DateFormat</code>
     * <code>Calendar.getInstance</code> is returned.
     */
    private Calendar getCalendar() {
        Format f = getFormat();

        if (f instanceof DateFormat) {
            return ((DateFormat)f).getCalendar();
        }
        return Calendar.getInstance();
    }


    /**
     * Returns true, as DateFormatterFilter will support
     * incrementing/decrementing of the value.
     */
    boolean getSupportsIncrement() {
        return true;
    }

    /**
     * Returns the field that will be adjusted by adjustValue.
     */
    Object getAdjustField(int start, Map<?, ?> attributes) {
        for (Object key : attributes.keySet()) {
            if ((key instanceof DateFormat.Field) &&
                (key == DateFormat.Field.HOUR1 ||
                 ((DateFormat.Field)key).getCalendarField() != -1)) {
                return key;
            }
        }
        return null;
    }

    /**
     * Adjusts the Date if FieldPosition identifies a known calendar
     * field.
     */
    Object adjustValue(Object value, Map<?, ?> attributes, Object key,
                           int direction) throws
                      BadLocationException, ParseException {
        if (key != null) {
            int field;

            // HOUR1 has no corresponding calendar field, thus, map
            // it to HOUR0 which will give the correct behavior.
            if (key == DateFormat.Field.HOUR1) {
                key = DateFormat.Field.HOUR0;
            }
            field = ((DateFormat.Field)key).getCalendarField();

            Calendar calendar = getCalendar();

            if (calendar != null) {
                calendar.setTime((Date)value);

                int fieldValue = calendar.get(field);

                try {
                    calendar.add(field, direction);
                    value = calendar.getTime();
                } catch (Throwable th) {
                    value = null;
                }
                return value;
            }
        }
        return null;
    }
}