Java tutorial
/* =========================================================== * JFreeChart : a free chart library for the Java(tm) platform * =========================================================== * * (C) Copyright 2000-2013, 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. * * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. * Other names may be trademarks of their respective owners.] * * --------------------- * FixedMillisecond.java * --------------------- * (C) Copyright 2002-2008, by Object Refinery Limited. * * Original Author: David Gilbert (for Object Refinery Limited); * Contributor(s): -; * * Changes * ------- * 19-Mar-2002 : Version 1, based on original Millisecond implementation (DG); * 24-Jun-2002 : Removed unnecessary imports (DG); * 10-Sep-2002 : Added getSerialIndex() method (DG); * 07-Oct-2002 : Fixed errors reported by Checkstyle (DG); * 13-Mar-2003 : Moved to com.jrefinery.data.time package and implemented * Serializable (DG); * 21-Oct-2003 : Added hashCode() method (DG); * ------------- JFREECHART 1.0.x --------------------------------------------- * 06-Oct-2006 : Added peg() method (DG); * 28-May-2008 : Fixed immutability problem (DG); * */ package org.jfree.data.time; import java.io.Serializable; import java.util.Calendar; import java.util.Date; /** * Wrapper for a <code>java.util.Date</code> object that allows it to be used * as a {@link RegularTimePeriod}. This class is immutable, which is a * requirement for all {@link RegularTimePeriod} subclasses. */ public class FixedMillisecond extends RegularTimePeriod implements Serializable { /** For serialization. */ private static final long serialVersionUID = 7867521484545646931L; /** The millisecond. */ private long time; /** * Constructs a millisecond based on the current system time. */ public FixedMillisecond() { this(new Date()); } /** * Constructs a millisecond. * * @param millisecond the millisecond (same encoding as java.util.Date). */ public FixedMillisecond(long millisecond) { this(new Date(millisecond)); } /** * Constructs a millisecond. * * @param time the time. */ public FixedMillisecond(Date time) { this.time = time.getTime(); } /** * Returns the date/time. * * @return The date/time. */ public Date getTime() { return new Date(this.time); } /** * This method is overridden to do nothing. * * @param calendar ignored * * @since 1.0.3 */ @Override public void peg(Calendar calendar) { // nothing to do } /** * Returns the millisecond preceding this one. * * @return The millisecond preceding this one. */ @Override public RegularTimePeriod previous() { RegularTimePeriod result = null; long t = this.time; if (t != Long.MIN_VALUE) { result = new FixedMillisecond(t - 1); } return result; } /** * Returns the millisecond following this one. * * @return The millisecond following this one. */ @Override public RegularTimePeriod next() { RegularTimePeriod result = null; long t = this.time; if (t != Long.MAX_VALUE) { result = new FixedMillisecond(t + 1); } return result; } /** * Tests the equality of this object against an arbitrary Object. * * @param object the object to compare * * @return A boolean. */ @Override public boolean equals(Object object) { if (object instanceof FixedMillisecond) { FixedMillisecond m = (FixedMillisecond) object; return this.time == m.getFirstMillisecond(); } else { return false; } } /** * Returns a hash code for this object instance. * * @return A hash code. */ @Override public int hashCode() { return (int) this.time; } /** * Returns an integer indicating the order of this Millisecond object * relative to the specified * object: negative == before, zero == same, positive == after. * * @param o1 the object to compare. * * @return negative == before, zero == same, positive == after. */ @Override public int compareTo(Object o1) { int result; long difference; // CASE 1 : Comparing to another Second object // ------------------------------------------- if (o1 instanceof FixedMillisecond) { FixedMillisecond t1 = (FixedMillisecond) o1; difference = this.time - t1.time; if (difference > 0) { result = 1; } else { if (difference < 0) { result = -1; } else { result = 0; } } } // CASE 2 : Comparing to another TimePeriod object // ----------------------------------------------- else if (o1 instanceof RegularTimePeriod) { // more difficult case - evaluate later... result = 0; } // CASE 3 : Comparing to a non-TimePeriod object // --------------------------------------------- else { // consider time periods to be ordered after general objects result = 1; } return result; } /** * Returns the first millisecond of the time period. * * @return The first millisecond of the time period. */ @Override public long getFirstMillisecond() { return this.time; } /** * Returns the first millisecond of the time period. * * @param calendar the calendar. * * @return The first millisecond of the time period. */ @Override public long getFirstMillisecond(Calendar calendar) { return this.time; } /** * Returns the last millisecond of the time period. * * @return The last millisecond of the time period. */ @Override public long getLastMillisecond() { return this.time; } /** * Returns the last millisecond of the time period. * * @param calendar the calendar. * * @return The last millisecond of the time period. */ @Override public long getLastMillisecond(Calendar calendar) { return this.time; } /** * Returns the millisecond closest to the middle of the time period. * * @return The millisecond closest to the middle of the time period. */ @Override public long getMiddleMillisecond() { return this.time; } /** * Returns the millisecond closest to the middle of the time period. * * @param calendar the calendar. * * @return The millisecond closest to the middle of the time period. */ @Override public long getMiddleMillisecond(Calendar calendar) { return this.time; } /** * Returns a serial index number for the millisecond. * * @return The serial index number. */ @Override public long getSerialIndex() { return this.time; } }