relativedateformat.java

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/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * -----------------------
 * RelativeDateFormat.java
 * -----------------------
 * (C) Copyright 2006-2008, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   Michael Siemer;
 *
 * Changes:
 * --------
 * 01-Nov-2006 : Version 1 (DG);
 * 23-Nov-2006 : Added argument checks, updated equals(), added clone() and
 *               hashCode() (DG);
 * 15-Feb-2008 : Applied patch 1873328 by Michael Siemer, with minor
 *               modifications (DG);
 * 01-Sep-2008 : Added new fields for hour and minute formatting, based on
 *               patch 2033092 (DG);
 *
 */

package org.jfree.chart.util;

import java.text.DateFormat;
import java.text.DecimalFormat;
import java.text.FieldPosition;
import java.text.NumberFormat;
import java.text.ParsePosition;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

/**
 * A formatter that formats dates to show the elapsed time relative to some
 * base date.
 *
 * @since 1.0.3
 */
public class RelativeDateFormat extends DateFormat {

    /** The base milliseconds for the elapsed time calculation. */
    private long baseMillis;

    /**
     * A flag that controls whether or not a zero day count is displayed.
     */
    private boolean showZeroDays;

    /**
     * A flag that controls whether or not a zero hour count is displayed.
     *
     * @since 1.0.10
     */
    private boolean showZeroHours;

    /**
     * A formatter for the day count (most likely not critical until the
     * day count exceeds 999).
     */
    private NumberFormat dayFormatter;

    /**
     * A prefix prepended to the start of the format if the relative date is
     * positive.
     *
     * @since 1.0.10
     */
    private String positivePrefix;

    /**
     * A string appended after the day count.
     */
    private String daySuffix;

    /**
     * A formatter for the hours.
     *
     * @since 1.0.11
     */
    private NumberFormat hourFormatter;

    /**
     * A string appended after the hours.
     */
    private String hourSuffix;

    /**
     * A formatter for the minutes.
     *
     * @since 1.0.11
     */
    private NumberFormat minuteFormatter;

    /**
     * A string appended after the minutes.
     */
    private String minuteSuffix;

    /**
     * A formatter for the seconds (and milliseconds).
     */
    private NumberFormat secondFormatter;

    /**
     * A string appended after the seconds.
     */
    private String secondSuffix;

    /**
     * A constant for the number of milliseconds in one hour.
     */
    private static long MILLISECONDS_IN_ONE_HOUR = 60 * 60 * 1000L;

    /**
     * A constant for the number of milliseconds in one day.
     */
    private static long MILLISECONDS_IN_ONE_DAY = 24 * MILLISECONDS_IN_ONE_HOUR;

    /**
     * Creates a new instance with base milliseconds set to zero.
     */
    public RelativeDateFormat() {
        this(0L);
    }

    /**
     * Creates a new instance.
     *
     * @param time  the date/time (<code>null</code> not permitted).
     */
    public RelativeDateFormat(Date time) {
        this(time.getTime());
    }

    /**
     * Creates a new instance.
     *
     * @param baseMillis  the time zone (<code>null</code> not permitted).
     */
    public RelativeDateFormat(long baseMillis) {
        super();
        this.baseMillis = baseMillis;
        this.showZeroDays = false;
        this.showZeroHours = true;
        this.positivePrefix = "";
        this.dayFormatter = NumberFormat.getNumberInstance();
        this.daySuffix = "d";
        this.hourFormatter = NumberFormat.getNumberInstance();
        this.hourSuffix = "h";
        this.minuteFormatter = NumberFormat.getNumberInstance();
        this.minuteSuffix = "m";
        this.secondFormatter = NumberFormat.getNumberInstance();
        this.secondFormatter.setMaximumFractionDigits(3);
        this.secondFormatter.setMinimumFractionDigits(3);
        this.secondSuffix = "s";

        // we don't use the calendar or numberFormat fields, but equals(Object)
        // is failing without them being non-null
        this.calendar = new GregorianCalendar();
        this.numberFormat = new DecimalFormat("0");
    }

    /**
     * Returns the base date/time used to calculate the elapsed time for
     * display.
     *
     * @return The base date/time in milliseconds since 1-Jan-1970.
     *
     * @see #setBaseMillis(long)
     */
    public long getBaseMillis() {
        return this.baseMillis;
    }

    /**
     * Sets the base date/time used to calculate the elapsed time for display.
     * This should be specified in milliseconds using the same encoding as
     * <code>java.util.Date</code>.
     *
     * @param baseMillis  the base date/time in milliseconds.
     *
     * @see #getBaseMillis()
     */
    public void setBaseMillis(long baseMillis) {
        this.baseMillis = baseMillis;
    }

    /**
     * Returns the flag that controls whether or not zero day counts are
     * shown in the formatted output.
     *
     * @return The flag.
     *
     * @see #setShowZeroDays(boolean)
     */
    public boolean getShowZeroDays() {
        return this.showZeroDays;
    }

    /**
     * Sets the flag that controls whether or not zero day counts are shown
     * in the formatted output.
     *
     * @param show  the flag.
     *
     * @see #getShowZeroDays()
     */
    public void setShowZeroDays(boolean show) {
        this.showZeroDays = show;
    }

    /**
     * Returns the flag that controls whether or not zero hour counts are
     * shown in the formatted output.
     *
     * @return The flag.
     *
     * @see #setShowZeroHours(boolean)
     *
     * @since 1.0.10
     */
    public boolean getShowZeroHours() {
        return this.showZeroHours;
    }

    /**
     * Sets the flag that controls whether or not zero hour counts are shown
     * in the formatted output.
     *
     * @param show  the flag.
     *
     * @see #getShowZeroHours()
     *
     * @since 1.0.10
     */
    public void setShowZeroHours(boolean show) {
        this.showZeroHours = show;
    }

    /**
     * Returns the string that is prepended to the format if the relative time
     * is positive.
     *
     * @return The string (never <code>null</code>).
     *
     * @see #setPositivePrefix(String)
     *
     * @since 1.0.10
     */
    public String getPositivePrefix() {
        return this.positivePrefix;
    }

    /**
     * Sets the string that is prepended to the format if the relative time is
     * positive.
     *
     * @param prefix  the prefix (<code>null</code> not permitted).
     *
     * @see #getPositivePrefix()
     *
     * @since 1.0.10
     */
    public void setPositivePrefix(String prefix) {
        if (prefix == null) {
            throw new IllegalArgumentException("Null 'prefix' argument.");
        }
        this.positivePrefix = prefix;
    }

    /**
     * Sets the formatter for the days.
     *
     * @param formatter  the formatter (<code>null</code> not permitted).
     *
     * @since 1.0.11
     */
    public void setDayFormatter(NumberFormat formatter) {
        if (formatter == null) {
            throw new IllegalArgumentException("Null 'formatter' argument.");
        }
        this.dayFormatter = formatter;
    }

    /**
     * Returns the string that is appended to the day count.
     *
     * @return The string.
     *
     * @see #setDaySuffix(String)