Source for org.jfree.data.ComparableObjectItem

   1: /* ===========================================================
   2:  * JFreeChart : a free chart library for the Java(tm) platform
   3:  * ===========================================================
   4:  *
   5:  * (C) Copyright 2000-2006, by Object Refinery Limited and Contributors.
   6:  *
   7:  * Project Info:  http://www.jfree.org/jfreechart/index.html
   8:  *
   9:  * This library is free software; you can redistribute it and/or modify it 
  10:  * under the terms of the GNU Lesser General Public License as published by 
  11:  * the Free Software Foundation; either version 2.1 of the License, or 
  12:  * (at your option) any later version.
  13:  *
  14:  * This library is distributed in the hope that it will be useful, but 
  15:  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
  16:  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
  17:  * License for more details.
  18:  *
  19:  * You should have received a copy of the GNU Lesser General Public
  20:  * License along with this library; if not, write to the Free Software
  21:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
  22:  * USA.  
  23:  *
  24:  * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
  25:  * in the United States and other countries.]
  26:  *
  27:  * -------------------------
  28:  * ComparableObjectItem.java
  29:  * -------------------------
  30:  * (C) Copyright 2006, by Object Refinery Limited.
  31:  *
  32:  * Original Author:  David Gilbert (for Object Refinery Limited);
  33:  * Contributor(s):   -;
  34:  *
  35:  * $Id: ComparableObjectItem.java,v 1.1.2.1 2006/10/20 15:23:22 mungady Exp $
  36:  *
  37:  * Changes
  38:  * -------
  39:  * 19-Oct-2006 : New class, based on XYDataItem (DG);
  40:  *
  41:  */
  42: 
  43: package org.jfree.data;
  44: 
  45: import java.io.Serializable;
  46: 
  47: import org.jfree.util.ObjectUtilities;
  48: 
  49: /**
  50:  * Represents one (Comparable, Object) data item for use in a 
  51:  * {@link ComparableObjectSeries}.
  52:  *
  53:  * @since 1.0.3
  54:  */
  55: public class ComparableObjectItem implements Cloneable, Comparable, 
  56:         Serializable {
  57: 
  58:     private static final long serialVersionUID = 2751513470325494890L;
  59:     
  60:     /** The x-value. */
  61:     private Comparable x;
  62: 
  63:     /** The y-value. */
  64:     private Object obj;
  65: 
  66:     /**
  67:      * Constructs a new data item.
  68:      *
  69:      * @param x  the x-value (<code>null</code> NOT permitted).
  70:      * @param y  the y-value (<code>null</code> permitted).
  71:      */
  72:     public ComparableObjectItem(Comparable x, Object y) {
  73:         if (x == null) {
  74:             throw new IllegalArgumentException("Null 'x' argument.");
  75:         }
  76:         this.x = x;
  77:         this.obj = y;
  78:     }
  79: 
  80:     /**
  81:      * Returns the x-value.
  82:      *
  83:      * @return The x-value (never <code>null</code>).
  84:      */
  85:     protected Comparable getComparable() {
  86:         return this.x;
  87:     }
  88: 
  89:     /**
  90:      * Returns the y-value.
  91:      *
  92:      * @return The y-value (possibly <code>null</code>).
  93:      */
  94:     protected Object getObject() {
  95:         return this.obj;
  96:     }
  97: 
  98:     /**
  99:      * Sets the y-value for this data item.  Note that there is no 
 100:      * corresponding method to change the x-value.
 101:      *
 102:      * @param y  the new y-value (<code>null</code> permitted).
 103:      */
 104:     protected void setObject(Object y) {
 105:         this.obj = y;
 106:     }
 107: 
 108:     /**
 109:      * Returns an integer indicating the order of this object relative to 
 110:      * another object.
 111:      * <P>
 112:      * For the order we consider only the x-value:
 113:      * negative == "less-than", zero == "equal", positive == "greater-than".
 114:      *
 115:      * @param o1  the object being compared to.
 116:      *
 117:      * @return An integer indicating the order of this data pair object
 118:      *      relative to another object.
 119:      */
 120:     public int compareTo(Object o1) {
 121: 
 122:         int result;
 123: 
 124:         // CASE 1 : Comparing to another ComparableObjectItem object
 125:         // ---------------------------------------------------------
 126:         if (o1 instanceof ComparableObjectItem) {
 127:             ComparableObjectItem that = (ComparableObjectItem) o1;
 128:             return this.x.compareTo(that.x);
 129:         }
 130: 
 131:         // CASE 2 : Comparing to a general object
 132:         // ---------------------------------------------
 133:         else {
 134:             // consider these to be ordered after general objects
 135:             result = 1;
 136:         }
 137: 
 138:         return result;
 139: 
 140:     }
 141: 
 142:     /**
 143:      * Returns a clone of this object.
 144:      *
 145:      * @return A clone.
 146:      * 
 147:      * @throws CloneNotSupportedException not thrown by this class, but 
 148:      *         subclasses may differ.
 149:      */
 150:     public Object clone() throws CloneNotSupportedException {
 151:         return super.clone();
 152:     }
 153:     
 154:     /**
 155:      * Tests if this object is equal to another.
 156:      *
 157:      * @param obj  the object to test against for equality (<code>null</code>
 158:      *             permitted).
 159:      *
 160:      * @return A boolean.
 161:      */
 162:     public boolean equals(Object obj) {
 163:         if (obj == this) {
 164:             return true;
 165:         }
 166:         if (!(obj instanceof ComparableObjectItem)) {
 167:             return false;
 168:         }
 169:         ComparableObjectItem that = (ComparableObjectItem) obj;
 170:         if (!this.x.equals(that.x)) {
 171:             return false;
 172:         }
 173:         if (!ObjectUtilities.equal(this.obj, that.obj)) {
 174:             return false;
 175:         }
 176:         return true;        
 177:     }
 178: 
 179:     /**
 180:      * Returns a hash code.
 181:      * 
 182:      * @return A hash code.
 183:      */
 184:     public int hashCode() {
 185:         int result;
 186:         result = this.x.hashCode();
 187:         result = 29 * result + (this.obj != null ? this.obj.hashCode() : 0);
 188:         return result;
 189:     }
 190:     
 191: }