Source for org.jfree.chart.plot.AbstractPieLabelDistributor

   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:  * AbstractPieLabelDistributor.java
  29:  * --------------------------------
  30:  * (C) Copyright 2007, by Object Refinery Limited and Contributors.
  31:  *
  32:  * Original Author:  David Gilbert (for Object Refinery Limited);
  33:  * Contributor(s):   -;
  34:  *
  35:  * Changes
  36:  * -------
  37:  * 14-Jun-2007 : Version 1 (DG);
  38:  *
  39:  */
  40: 
  41: package org.jfree.chart.plot;
  42: 
  43: import java.io.Serializable;
  44: import java.util.List;
  45: 
  46: /**
  47:  * A base class for handling the distribution of pie section labels.  Create
  48:  * your own subclass and set it using the 
  49:  * {@link PiePlot#setLabelDistributor(AbstractPieLabelDistributor)} method
  50:  * if you want to customise the label distribution.
  51:  */
  52: public abstract class AbstractPieLabelDistributor implements Serializable {
  53: 
  54:     /** The label records. */
  55:     protected List labels;
  56: 
  57:     /**
  58:      * Creates a new instance.
  59:      */
  60:     public AbstractPieLabelDistributor() {
  61:         this.labels = new java.util.ArrayList();
  62:     }
  63: 
  64:     /**
  65:      * Returns a label record from the list.
  66:      * 
  67:      * @param index  the index.
  68:      * 
  69:      * @return The label record.
  70:      */
  71:     public PieLabelRecord getPieLabelRecord(int index) {
  72:         return (PieLabelRecord) this.labels.get(index);   
  73:     }
  74:     
  75:     /**
  76:      * Adds a label record.
  77:      * 
  78:      * @param record  the label record (<code>null</code> not permitted).
  79:      */
  80:     public void addPieLabelRecord(PieLabelRecord record) {
  81:         if (record == null) {
  82:             throw new IllegalArgumentException("Null 'record' argument.");
  83:         }
  84:         this.labels.add(record);
  85:     }
  86:     
  87:     /**
  88:      * Returns the number of items in the list.
  89:      * 
  90:      * @return The item count.
  91:      */
  92:     public int getItemCount() {
  93:         return this.labels.size();   
  94:     }
  95:     
  96:     /**
  97:      * Clears the list of labels.
  98:      */
  99:     public void clear() {
 100:         this.labels.clear();
 101:     }
 102:     
 103:     /**
 104:      * Called by the {@link PiePlot} class.  Implementations should distribute
 105:      * the labels in this.labels then return.
 106:      * 
 107:      * @param minY  the y-coordinate for the top of the label area.
 108:      * @param height  the height of the label area.
 109:      */
 110:     public abstract void distributeLabels(double minY, double height);
 111:     
 112: }