org.jfree.data.time.SimpleTimePeriod Maven / Gradle / Ivy
/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-2005, 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.]
*
* ---------------------
* SimpleTimePeriod.java
* ---------------------
* (C) Copyright 2002-2005, by Object Refinery Limited and Contributors.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* $Id: SimpleTimePeriod.java,v 1.5.2.1 2005/10/25 21:35:24 mungady Exp $
*
* Changes
* -------
* 07-Oct-2002 : Added Javadocs (DG);
* 10-Jan-2003 : Renamed TimeAllocation --> SimpleTimePeriod (DG);
* 13-Mar-2003 : Added equals() method, and Serializable interface (DG);
* 21-Oct-2003 : Added hashCode() method (DG);
* 27-Jan-2005 : Implemented Comparable, to enable this class to be used
* in the TimeTableXYDataset class (DG);
*
*/
package org.jfree.data.time;
import java.io.Serializable;
import java.util.Date;
/**
* An arbitrary period of time, measured to millisecond precision using
* java.util.Date.
*
* This class is intentionally immutable (that is, once constructed, you cannot
* alter the start and end attributes).
*/
public class SimpleTimePeriod implements TimePeriod, Comparable, Serializable {
/** For serialization. */
private static final long serialVersionUID = 8684672361131829554L;
/** The start date/time. */
private Date start;
/** The end date/time. */
private Date end;
/**
* Creates a new time allocation.
*
* @param start the start date/time in milliseconds.
* @param end the end date/time in milliseconds.
*/
public SimpleTimePeriod(long start, long end) {
this(new Date(start), new Date(end));
}
/**
* Creates a new time allocation.
*
* @param start the start date/time (null not permitted).
* @param end the end date/time (null not permitted).
*/
public SimpleTimePeriod(Date start, Date end) {
if (start.getTime() > end.getTime()) {
throw new IllegalArgumentException("Requires end >= start.");
}
this.start = start;
this.end = end;
}
/**
* Returns the start date/time.
*
* @return The start date/time (never null).
*/
public Date getStart() {
return this.start;
}
/**
* Returns the end date/time.
*
* @return The end date/time (never null).
*/
public Date getEnd() {
return this.end;
}
/**
* Tests this time period instance for equality with an arbitrary object.
* The object is considered equal if it is an instance of {@link TimePeriod}
* and it has the same start and end dates.
*
* @param obj the other object (null permitted).
*
* @return A boolean.
*/
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof TimePeriod)) {
return false;
}
TimePeriod that = (TimePeriod) obj;
if (!this.start.equals(that.getStart())) {
return false;
}
if (!this.end.equals(that.getEnd())) {
return false;
}
return true;
}
/**
* Returns an integer that indicates the relative ordering of two
* time periods.
*
* @param obj the object (null not permitted).
*
* @return An integer.
*
* @throws ClassCastException if obj is not an instance of
* {@link TimePeriod}.
*/
public int compareTo(Object obj) {
TimePeriod that = (TimePeriod) obj;
long t0 = getStart().getTime();
long t1 = getEnd().getTime();
long m0 = t0 + (t1 - t0) / 2L;
long t2 = that.getStart().getTime();
long t3 = that.getEnd().getTime();
long m1 = t2 + (t3 - t2) / 2L;
if (m0 < m1) {
return -1;
}
else if (m0 > m1) {
return 1;
}
else {
if (t0 < t2) {
return -1;
}
else if (t0 > t2) {
return 1;
}
else {
if (t1 < t3) {
return -1;
}
else if (t1 > t3) {
return 1;
}
else {
return 0;
}
}
}
}
/**
* Returns a hash code for this object instance. The approach described by
* Joshua Bloch in "Effective Java" has been used here - see:
*
* http://developer.java.sun.com/
* developer/Books/effectivejava/Chapter3.pdf
*
* @return A hash code.
*/
public int hashCode() {
int result = 17;
result = 37 * result + this.start.hashCode();
result = 37 * result + this.end.hashCode();
return result;
}
}