CumulativeScatterplot.java

/*
    BeepBeep, an event stream processor
    Copyright (C) 2008-2017 Sylvain Hallé

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published
    by the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package plots;

import ca.uqac.lif.cep.Connector;
import static ca.uqac.lif.cep.Connector.TOP;
import static ca.uqac.lif.cep.Connector.BOTTOM;
import ca.uqac.lif.cep.mtnp.DrawPlot;
import ca.uqac.lif.cep.mtnp.UpdateTable;
import ca.uqac.lif.cep.mtnp.UpdateTableStream;
import ca.uqac.lif.cep.tmf.Pump;
import ca.uqac.lif.cep.tmf.QueueSource;
import ca.uqac.lif.mtnp.plot.gral.Scatterplot;

/**
 * Update a 2D scatterplot in realtime from two streams of numbers.
 * This example generates dummy (x,y) pairs of numbers, accumulates them
 * into a table, and shows a scatterplot of those numbers in a window
 * such as this one:
 * <p>
 * <img src="./doc-files/plots/window-plot.png" alt="Processor graph" width="400">  
 * <p> 
 * Graphically, this chain of processor can be described as follows:
 * <p>
 * <img src="./doc-files/plots/CumulativeScatterplot.png" alt="Processor graph">
 * @author Sylvain Hallé
 * @difficulty Easy
 */
public class CumulativeScatterplot
{

    public static void main(String[] args) throws InterruptedException
    {
        /* A stream of (x,y) pairs is first created,
         * with x an incrementing integer, and y a randomly selected number
         * (see {@link RandomTwoD}).
        */
        ///
        QueueSource one = new QueueSource().setEvents(1);
        Pump pump = new Pump(1000);
        RandomTwoD random = new RandomTwoD();
        Connector.connect(one, pump, random);

        /* The resulting x-stream and y-streams are then pushed into an
         * {@link UpdateTableStream} processor. We instantiate this processor,
         * telling it to create an empty {@link Table} object with two
         * columns, called "x" and "y". */
        UpdateTable table = new UpdateTableStream("x", "y");
        
        /* This creates a processor with two input streams, one for the "x"
         * values, and the other for the "y" values. Each pair of values from
         * the x and y streams is used to append a new line to the (initially
         * empty) table. We connect the two
         * outputs of the random processor to these two inputs. */
        Connector.connect(random, TOP, table, TOP);
        Connector.connect(random, BOTTOM, table, BOTTOM);

        /* The next step is to create a plot out of the table's content.
         * The {@link DrawPlot} processor receives a Table and passes it to
         * a {@link ca.uqac.lif.mtnp.Plot Plot} object from the MTNP
         * library. In our case, we want to create a scatterplot from the
         * table's contents. */
        DrawPlot draw = new DrawPlot(new Scatterplot());
        Connector.connect(table, draw);

        /* Each event that comes out of the DrawPlot processor is an array
         * of bytes corresponding to a bitmap image. To display that image,
         * we use the BitmapJFrame processor, which opens a window and
         * displays the image inside. */
        BitmapJFrame window = new BitmapJFrame();
        Connector.connect(draw, window);
        
        /* We need to call the start() method so that the window becomes
         * visible. */
        window.start();

        /* All set! We'll now repeatedly tell the source to push events
         * out. You should see the window being updated every second with
         * more and more data points.
         */
        System.out.println("Displaying plot. Press Ctrl+C "
            + "or close the window to end.");
        Thread th = new Thread(pump);
        th.start();
        ///
    }
}