Source for org.jfree.data.general.DefaultKeyedValueDataset

   1: /* ===========================================================
   2:  * JFreeChart : a free chart library for the Java(tm) platform
   3:  * ===========================================================
   4:  *
   5:  * (C) Copyright 2000-2007, 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:  * DefaultKeyedValueDataset.java
  29:  * -----------------------------
  30:  * (C) Copyright 2003-2007, by Object Refinery Limited.
  31:  *
  32:  * Original Author:  David Gilbert (for Object Refinery Limited);
  33:  * Contributor(s):   -;
  34:  *
  35:  * Changes
  36:  * -------
  37:  * 27-Mar-2003 : Version 1 (DG);
  38:  * 18-Aug-2003 : Implemented Cloneable (DG);
  39:  *
  40:  */
  41: 
  42: package org.jfree.data.general;
  43: 
  44: import java.io.Serializable;
  45: 
  46: import org.jfree.data.DefaultKeyedValue;
  47: import org.jfree.data.KeyedValue;
  48: import org.jfree.util.ObjectUtilities;
  49: 
  50: /**
  51:  * A default implementation of the {@link KeyedValueDataset} interface.
  52:  */
  53: public class DefaultKeyedValueDataset extends AbstractDataset
  54:                                       implements KeyedValueDataset, 
  55:                                                  Serializable {
  56: 
  57:     /** For serialization. */
  58:     private static final long serialVersionUID = -8149484339560406750L;
  59:     
  60:     /** Storage for the data. */
  61:     private KeyedValue data;
  62: 
  63:     /**
  64:      * Constructs a new dataset, initially empty.
  65:      */
  66:     public DefaultKeyedValueDataset() {
  67:         this(null);
  68:     }
  69: 
  70:     /**
  71:      * Creates a new dataset with the specified initial value.
  72:      *
  73:      * @param key  the key.
  74:      * @param value  the value (<code>null</code> permitted).
  75:      */
  76:     public DefaultKeyedValueDataset(Comparable key, Number value) {
  77:         this(new DefaultKeyedValue(key, value));
  78:     }
  79: 
  80:     /**
  81:      * Creates a new dataset that uses the data from a {@link KeyedValue} 
  82:      * instance.
  83:      *
  84:      * @param data  the data (<code>null</code> permitted).
  85:      */
  86:     public DefaultKeyedValueDataset(KeyedValue data) {
  87:         this.data = data;
  88:     }
  89: 
  90:     /**
  91:      * Returns the key associated with the value, or <code>null</code> if the 
  92:      * dataset has no data item.
  93:      *
  94:      * @return The key.
  95:      */
  96:     public Comparable getKey() {
  97:         Comparable result = null;
  98:         if (this.data != null) {
  99:             result = this.data.getKey();
 100:         }
 101:         return result;
 102:     }
 103: 
 104:     /**
 105:      * Returns the value.
 106:      *
 107:      * @return The value (possibly <code>null</code>).
 108:      */
 109:     public Number getValue() {
 110:         Number result = null;
 111:         if (this.data != null) {
 112:             result = this.data.getValue();
 113:         }
 114:         return result;
 115:     }
 116: 
 117:     /**
 118:      * Updates the value.
 119:      *
 120:      * @param value  the new value (<code>null</code> permitted).
 121:      */
 122:     public void updateValue(Number value) {
 123:         if (this.data == null) {
 124:             throw new RuntimeException("updateValue: can't update null.");
 125:         }
 126:         setValue(this.data.getKey(), value);
 127:     }
 128: 
 129:     /**
 130:      * Sets the value for the dataset and sends a {@link DatasetChangeEvent} to 
 131:      * all registered listeners.
 132:      *
 133:      * @param key  the key.
 134:      * @param value  the value (<code>null</code> permitted).
 135:      */
 136:     public void setValue(Comparable key, Number value) {
 137:         this.data = new DefaultKeyedValue(key, value);
 138:         notifyListeners(new DatasetChangeEvent(this, this));
 139:     }
 140: 
 141:     /**
 142:      * Tests this dataset for equality with an arbitrary object.
 143:      *
 144:      * @param obj  the object.
 145:      *
 146:      * @return A boolean.
 147:      */
 148:     public boolean equals(Object obj) {
 149: 
 150:         if (obj == this) {
 151:             return true;
 152:         }
 153:         if (!(obj instanceof KeyedValueDataset)) {
 154:             return false;
 155:         }
 156:         KeyedValueDataset that = (KeyedValueDataset) obj;
 157:         if (this.data == null) {
 158:             if (that.getKey() != null || that.getValue() != null) {
 159:                 return false;
 160:             }
 161:             return true;
 162:         }
 163:         if (!ObjectUtilities.equal(this.data.getKey(), that.getKey())) {
 164:             return false;
 165:         }
 166:         if (!ObjectUtilities.equal(this.data.getValue(), that.getValue())) {
 167:             return false;
 168:         }
 169:         return true;
 170:     }
 171: 
 172:     /**
 173:      * Returns a hash code.
 174:      * 
 175:      * @return A hash code.
 176:      */
 177:     public int hashCode() {
 178:         return (this.data != null ? this.data.hashCode() : 0);
 179:     }
 180: 
 181:     /**
 182:      * Creates a clone of the dataset.
 183:      * 
 184:      * @return A clone.
 185:      * 
 186:      * @throws CloneNotSupportedException This class will not throw this 
 187:      *         exception, but subclasses (if any) might.
 188:      */
 189:     public Object clone() throws CloneNotSupportedException {
 190:         DefaultKeyedValueDataset clone 
 191:             = (DefaultKeyedValueDataset) super.clone();
 192:         return clone;    
 193:     }
 194:     
 195: }