Source for org.jfree.data.general.DefaultKeyedValueDataset

   1: /* ===========================================================
   2:  * JFreeChart : a free chart library for the Java(tm) platform
   3:  * ===========================================================
   4:  *
   5:  * (C) Copyright 2000-2005, 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 2003-2005, by Object Refinery Limited.
  31:  *
  32:  * Original Author:  David Gilbert (for Object Refinery Limited);
  33:  * Contributor(s):   -;
  34:  *
  35:  * $Id $
  36:  *
  37:  * Changes
  38:  * -------
  39:  * 27-Mar-2003 : Version 1 (DG);
  40:  * 18-Aug-2003 : Implemented Cloneable (DG);
  41:  *
  42:  */
  43: 
  44: package org.jfree.data.general;
  45: 
  46: import java.io.Serializable;
  47: 
  48: import org.jfree.data.DefaultKeyedValue;
  49: import org.jfree.data.KeyedValue;
  50: import org.jfree.util.ObjectUtilities;
  51: 
  52: /**
  53:  * A default implementation of the {@link KeyedValueDataset} interface.
  54:  */
  55: public class DefaultKeyedValueDataset extends AbstractDataset
  56:                                       implements KeyedValueDataset, 
  57:                                                  Serializable {
  58: 
  59:     /** For serialization. */
  60:     private static final long serialVersionUID = -8149484339560406750L;
  61:     
  62:     /** Storage for the data. */
  63:     private KeyedValue data;
  64: 
  65:     /**
  66:      * Constructs a new dataset, initially empty.
  67:      */
  68:     public DefaultKeyedValueDataset() {
  69:         this(null);
  70:     }
  71: 
  72:     /**
  73:      * Creates a new dataset with the specified initial value.
  74:      *
  75:      * @param key  the key.
  76:      * @param value  the value (<code>null</code> permitted).
  77:      */
  78:     public DefaultKeyedValueDataset(Comparable key, Number value) {
  79:         this(new DefaultKeyedValue(key, value));
  80:     }
  81: 
  82:     /**
  83:      * Creates a new dataset that uses the data from a {@link KeyedValue} 
  84:      * instance.
  85:      *
  86:      * @param data  the data (<code>null</code> permitted).
  87:      */
  88:     public DefaultKeyedValueDataset(KeyedValue data) {
  89:         this.data = data;
  90:     }
  91: 
  92:     /**
  93:      * Returns the key associated with the value, or <code>null</code> if the 
  94:      * dataset has no data item.
  95:      *
  96:      * @return The key.
  97:      */
  98:     public Comparable getKey() {
  99:         Comparable result = null;
 100:         if (this.data != null) {
 101:             result = this.data.getKey();
 102:         }
 103:         return result;
 104:     }
 105: 
 106:     /**
 107:      * Returns the value.
 108:      *
 109:      * @return The value (possibly <code>null</code>).
 110:      */
 111:     public Number getValue() {
 112:         Number result = null;
 113:         if (this.data != null) {
 114:             result = this.data.getValue();
 115:         }
 116:         return result;
 117:     }
 118: 
 119:     /**
 120:      * Updates the value.
 121:      *
 122:      * @param value  the new value (<code>null</code> permitted).
 123:      */
 124:     public void updateValue(Number value) {
 125:         if (this.data == null) {
 126:             throw new RuntimeException("updateValue: can't update null.");
 127:         }
 128:         setValue(this.data.getKey(), value);
 129:     }
 130: 
 131:     /**
 132:      * Sets the value for the dataset and sends a {@link DatasetChangeEvent} to 
 133:      * all registered listeners.
 134:      *
 135:      * @param key  the key.
 136:      * @param value  the value (<code>null</code> permitted).
 137:      */
 138:     public void setValue(Comparable key, Number value) {
 139:         this.data = new DefaultKeyedValue(key, value);
 140:         notifyListeners(new DatasetChangeEvent(this, this));
 141:     }
 142: 
 143:     /**
 144:      * Tests this dataset for equality with an arbitrary object.
 145:      *
 146:      * @param obj  the object.
 147:      *
 148:      * @return A boolean.
 149:      */
 150:     public boolean equals(Object obj) {
 151: 
 152:         if (obj == this) {
 153:             return true;
 154:         }
 155:         if (!(obj instanceof KeyedValueDataset)) {
 156:             return false;
 157:         }
 158:         KeyedValueDataset that = (KeyedValueDataset) obj;
 159:         if (this.data == null) {
 160:             if (that.getKey() != null || that.getValue() != null) {
 161:                 return false;
 162:             }
 163:             return true;
 164:         }
 165:         if (!ObjectUtilities.equal(this.data.getKey(), that.getKey())) {
 166:             return false;
 167:         }
 168:         if (!ObjectUtilities.equal(this.data.getValue(), that.getValue())) {
 169:             return false;
 170:         }
 171:         return true;
 172:     }
 173: 
 174:     /**
 175:      * Returns a hash code.
 176:      * 
 177:      * @return A hash code.
 178:      */
 179:     public int hashCode() {
 180:         return (this.data != null ? this.data.hashCode() : 0);
 181:     }
 182: 
 183:     /**
 184:      * Creates a clone of the dataset.
 185:      * 
 186:      * @return A clone.
 187:      * 
 188:      * @throws CloneNotSupportedException This class will not throw this 
 189:      *         exception, but subclasses (if any) might.
 190:      */
 191:     public Object clone() throws CloneNotSupportedException {
 192:         DefaultKeyedValueDataset clone 
 193:             = (DefaultKeyedValueDataset) super.clone();
 194:         return clone;    
 195:     }
 196:     
 197: }