001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2020, by Object Refinery Limited and Contributors.
006 *
007 * Project Info:  http://www.jfree.org/jfreechart/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
022 * USA.
023 *
024 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
025 * Other names may be trademarks of their respective owners.]
026 *
027 * -------------------
028 * HeatMapDataset.java
029 * -------------------
030 * (C) Copyright 2009-2016, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 */
036
037package org.jfree.data.general;
038
039/**
040 * A dataset that represents a rectangular grid of (x, y, z) values.  The x
041 * and y values appear at regular intervals in the dataset, while the z-values
042 * can take any value (including {@code null} for unknown values).
043 *
044 * @since 1.0.13
045 */
046public interface HeatMapDataset {
047
048    /**
049     * Returns the number of x values across the width of the dataset.  The
050     * values are evenly spaced between {@link #getMinimumXValue()} and
051     * {@link #getMaximumXValue()}.
052     * 
053     * @return The number of x-values (always > 0).
054     */
055    public int getXSampleCount();
056
057    /**
058     * Returns the number of y values (or samples) for the dataset.  The
059     * values are evenly spaced between {@link #getMinimumYValue()} and
060     * {@link #getMaximumYValue()}.
061     *
062     * @return The number of y-values (always > 0).
063     */
064    public int getYSampleCount();
065
066    /**
067     * Returns the lowest x-value represented in this dataset.  A requirement
068     * of this interface is that this method must never return infinite or
069     * Double.NAN values.
070     *
071     * @return The lowest x-value represented in this dataset.
072     */
073    public double getMinimumXValue();
074
075    /**
076     * Returns the highest x-value represented in this dataset.  A requirement
077     * of this interface is that this method must never return infinite or
078     * Double.NAN values.
079     *
080     * @return The highest x-value represented in this dataset.
081     */
082    public double getMaximumXValue();
083
084    /**
085     * Returns the lowest y-value represented in this dataset.  A requirement
086     * of this interface is that this method must never return infinite or
087     * Double.NAN values.
088     *
089     * @return The lowest y-value represented in this dataset.
090     */
091    public double getMinimumYValue();
092
093    /**
094     * Returns the highest y-value represented in this dataset.  A requirement
095     * of this interface is that this method must never return infinite or
096     * Double.NAN values.
097     *
098     * @return The highest y-value represented in this dataset.
099     */
100    public double getMaximumYValue();
101
102    /**
103     * A convenience method that returns the x-value for the given index.
104     * 
105     * @param xIndex  the xIndex.
106     * 
107     * @return The x-value.
108     */
109    public double getXValue(int xIndex);
110
111    /**
112     * A convenience method that returns the y-value for the given index.
113     * 
114     * @param yIndex  the yIndex.
115     * 
116     * @return The y-value.
117     */
118    public double getYValue(int yIndex);
119
120    /**
121     * Returns the z-value at the specified sample position in the dataset.
122     * For a missing or unknown value, this method should return Double.NAN.
123     *
124     * @param xIndex  the position of the x sample in the dataset.
125     * @param yIndex  the position of the y sample in the dataset.
126     *
127     * @return The z-value.
128     */
129    public double getZValue(int xIndex, int yIndex);
130
131    /**
132     * Returns the z-value at the specified sample position in the dataset.
133     * This method can return {@code null} to indicate a missing/unknown
134     * value.
135     * <br><br>
136     * Bear in mind that the class implementing this interface may
137     * store its data using primitives rather than objects, so calling this
138     * method may require a new {@code Number} object to be allocated...
139     * for this reason, it is generally preferable to use the
140     * {@link #getZValue(int, int)} method unless you *know* that the dataset
141     * implementation stores the z-values using objects.
142     *
143     * @param xIndex  the position of the x sample in the dataset.
144     * @param yIndex  the position of the y sample in the dataset.
145     *
146     * @return The z-value (possibly {@code null}).
147     */
148    public Number getZ(int xIndex, int yIndex);
149
150}