www.pudn.com > jfreechart-0.9.12.zip > DateTickUnit.java
/* ======================================
* JFreeChart : a free Java chart library
* ======================================
*
* Project Info: http://www.jfree.org/jfreechart/index.html
* Project Lead: David Gilbert (david.gilbert@object-refinery.com);
*
* (C) Copyright 2000-2003, by Object Refinery Limited and Contributors.
*
* 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.
*
* -----------------
* DateTickUnit.java
* -----------------
* (C) Copyright 2000-2003, by Object Refinery Limited.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* $Id: DateTickUnit.java,v 1.4 2003/08/15 11:47:06 mungady Exp $
*
* Changes (from 8-Nov-2002)
* --------------------------
* 08-Nov-2002 : Moved to new package com.jrefinery.chart.axis (DG);
* 27-Nov-2002 : Added IllegalArgumentException to getMillisecondCount(...) method (DG);
* 26-Mar-2003 : Implemented Serializable (DG);
*
*/
package org.jfree.chart.axis;
import java.io.Serializable;
import java.text.DateFormat;
import java.util.Calendar;
import java.util.Date;
/**
* A tick unit for use by subclasses of {@link DateAxis}.
*
* Instances of this class are immutable.
*
* @author David Gilbert
*/
public class DateTickUnit extends TickUnit implements Serializable {
/** A constant for years. */
public static final int YEAR = 0;
/** A constant for months. */
public static final int MONTH = 1;
/** A constant for days. */
public static final int DAY = 2;
/** A constant for hours. */
public static final int HOUR = 3;
/** A constant for minutes. */
public static final int MINUTE = 4;
/** A constant for seconds. */
public static final int SECOND = 5;
/** A constant for milliseconds. */
public static final int MILLISECOND = 6;
/** The unit. */
private int unit;
/** The unit count. */
private int count;
/** The date formatter. */
private DateFormat formatter;
/**
* Creates a new date tick unit. The dates will be formatted using a SHORT format for the
* default locale.
*
* @param unit the unit.
* @param count the unit count.
*/
public DateTickUnit(int unit, int count) {
this(unit, count, DateFormat.getDateInstance(DateFormat.SHORT));
}
/**
* Creates a new date tick unit.
*
* You can specify the units using one of the constants YEAR, MONTH, DAY, HOUR, MINUTE,
* SECOND or MILLISECOND. In addition, you can specify a unit count, and a date format.
*
* @param unit the unit.
* @param count the unit count.
* @param formatter the date formatter.
*/
public DateTickUnit(int unit, int count, DateFormat formatter) {
super(DateTickUnit.getMillisecondCount(unit, count));
this.unit = unit;
this.count = count;
this.formatter = formatter;
}
/**
* Returns the date unit. This will be one of the constants YEAR,
* MONTH, DAY, HOUR, MINUTE,
* SECOND or MILLISECOND, defined by this class. Note that these
* constants do NOT correspond to those defined in Java's Calendar class.
*
* @return the date unit.
*/
public int getUnit() {
return this.unit;
}
/**
* Returns the unit count.
*
* @return the unit count.
*/
public int getCount() {
return this.count;
}
/**
* Formats a value.
*
* @param milliseconds date in milliseconds since 01-01-1970.
*
* @return the formatted date.
*/
public String valueToString(double milliseconds) {
return formatter.format(new Date((long) milliseconds));
}
/**
* Formats a date using the tick unit's formatter.
*
* @param date the date.
*
* @return the formatted date.
*/
public String dateToString(Date date) {
return formatter.format(date);
}
/**
* Calculates a new date by adding this unit to the base date.
*
* @param base the base date.
*
* @return a new date one unit after the base date.
*/
public Date addToDate(Date base) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(base);
calendar.add(getCalendarField(this.unit), this.count);
return calendar.getTime();
}
/**
* Returns a field code that can be used with the Calendar class.
*
* @return the field code.
*/
public int getCalendarField() {
return getCalendarField(this.unit);
}
/**
* Returns a field code (that can be used with the Calendar class) for a given 'unit' code.
* The 'unit' is one of: YEAR, MONTH, DAY, HOUR, MINUTE, SECOND and MILLISECOND.
*
* @param unit the unit.
*
* @return the field code.
*/
private int getCalendarField(int unit) {
switch (unit) {
case (YEAR) : return Calendar.YEAR;
case (MONTH) : return Calendar.MONTH;
case (DAY) : return Calendar.DATE;
case (HOUR) : return Calendar.HOUR_OF_DAY;
case (MINUTE) : return Calendar.MINUTE;
case (SECOND) : return Calendar.SECOND;
case (MILLISECOND) : return Calendar.MILLISECOND;
default: return Calendar.MILLISECOND;
}
}
/**
* Returns the (approximate) number of milliseconds for the given unit and unit count.
*
* This value is an approximation some of the time (e.g. months are assumed to have 31 days)
* but this shouldn't matter.
*
* @param unit the unit.
* @param count the unit count.
*
* @return the number of milliseconds.
*/
private static long getMillisecondCount(int unit, int count) {
switch (unit) {
case (YEAR) : return (365L * 24L * 60L * 60L * 1000L) * count;
case (MONTH) : return (31L * 24L * 60L * 60L * 1000L) * count;
case (DAY) : return (24L * 60L * 60L * 1000L) * count;
case (HOUR) : return (60L * 60L * 1000L) * count;
case (MINUTE) : return (60L * 1000L) * count;
case (SECOND) : return 1000L * count;
case (MILLISECOND) : return (long) count;
default: throw new IllegalArgumentException("DateTickUnit.getMillisecondCount(...) : "
+ "unit must be one of the constants YEAR, MONTH, DAY, HOUR, "
+ "MINUTE, SECOND or MILLISECOND defined in the DateTickUnit class. "
+ "Do *not* use the constants defined in java.util.Calendar.");
}
}
/**
* Tests this unit for equality with another object.
*
* @param obj the object.
*
* @return true or false.
*/
public boolean equals(Object obj) {
if (obj == null) {
return false;
}
if (obj == this) {
return true;
}
if (obj instanceof DateTickUnit) {
DateTickUnit dtu = (DateTickUnit) obj;
if (super.equals(obj)) {
boolean b0 = (this.unit == dtu.unit) && (this.count == dtu.count);
boolean b1 = this.formatter.equals(dtu.formatter);
return b0 && b1;
}
else {
return false;
}
}
return false;
}
}