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.] * * -------------------- * TimePeriodValue.java * -------------------- * (C) Copyright 2003-2013, by Object Refinery Limited. * * Original Author: David Gilbert (for Object Refinery Limited); * Contributor(s): -; * * Changes * ------- * 22-Apr-2003 : Version 1 (DG); * 03-Oct-2006 : Added null argument check to constructor (DG); * 07-Apr-2008 : Added a toString() override for debugging (DG); * 02-Jul-2013 : Use ParamChecks (DG); * */ package org.jfree.data.time; import java.io.Serializable; import org.jfree.chart.util.ParamChecks; /** * Represents a time period and an associated value. */ public class TimePeriodValue implements Cloneable, Serializable { /** For serialization. */ private static final long serialVersionUID = 3390443360845711275L; /** The time period. */ private TimePeriod period; /** The value associated with the time period. */ private Number value; /** * Constructs a new data item. * * @param period the time period (<code>null</code> not permitted). * @param value the value associated with the time period. * * @throws IllegalArgumentException if <code>period</code> is * <code>null</code>. */ public TimePeriodValue(TimePeriod period, Number value) { ParamChecks.nullNotPermitted(period, "period"); this.period = period; this.value = value; } /** * Constructs a new data item. * * @param period the time period (<code>null</code> not permitted). * @param value the value associated with the time period. * * @throws IllegalArgumentException if <code>period</code> is * <code>null</code>. */ public TimePeriodValue(TimePeriod period, double value) { this(period, new Double(value)); } /** * Returns the time period. * * @return The time period (never <code>null</code>). */ public TimePeriod getPeriod() { return this.period; } /** * Returns the value. * * @return The value (possibly <code>null</code>). * * @see #setValue(Number) */ public Number getValue() { return this.value; } /** * Sets the value for this data item. * * @param value the new value (<code>null</code> permitted). * * @see #getValue() */ public void setValue(Number value) { this.value = value; } /** * Tests this object for equality with the target object. * * @param obj the object (<code>null</code> permitted). * * @return A boolean. */ @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (!(obj instanceof TimePeriodValue)) { return false; } TimePeriodValue timePeriodValue = (TimePeriodValue) obj; if (this.period != null ? !this.period.equals(timePeriodValue.period) : timePeriodValue.period != null) { return false; } if (this.value != null ? !this.value.equals(timePeriodValue.value) : timePeriodValue.value != null) { return false; } return true; } /** * Returns a hash code value for the object. * * @return The hashcode */ @Override public int hashCode() { int result; result = (this.period != null ? this.period.hashCode() : 0); result = 29 * result + (this.value != null ? this.value.hashCode() : 0); return result; } /** * Clones the object. * <P> * Note: no need to clone the period or value since they are immutable * classes. * * @return A clone. */ @Override public Object clone() { Object clone = null; try { clone = super.clone(); } catch (CloneNotSupportedException e) { // won't get here... throw new RuntimeException(e); } return clone; } /** * Returns a string representing this instance, primarily for use in * debugging. * * @return A string. */ @Override public String toString() { return "TimePeriodValue[" + getPeriod() + "," + getValue() + "]"; } }