WindowSimple.java

/*
    BeepBeep, an event stream processor
    Copyright (C) 2008-2018 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 basic;

import ca.uqac.lif.cep.Connector;
import ca.uqac.lif.cep.Pullable;
import ca.uqac.lif.cep.functions.Cumulate;
import ca.uqac.lif.cep.functions.CumulativeFunction;
import ca.uqac.lif.cep.tmf.QueueSource;
import ca.uqac.lif.cep.tmf.Window;
import ca.uqac.lif.cep.util.Numbers;

/**
 * Use a {@link ca.uqac.lif.cep.tmf.Window Window} processor to perform a
 * computation over a sliding window of events.
 * The chain of processors in this example can be
 * represented graphically as:
 * <p>
 * <img src="./doc-files/basic/WindowSimple.png" alt="Processor graph">
 * @author Sylvain Hallé
 * @difficulty Easy
 */
public class WindowSimple
{
    public static void main(String[] args)
    {
        /// Create a source of arbitrary numbers
        QueueSource source = new QueueSource().setEvents(1, 2, 3, 4, 5, 6);
        
        // Create a cumulate processor
        Cumulate sum = new Cumulate(
                new CumulativeFunction<Number>(Numbers.addition));
        
        // Create a window processor of width 3, using sum as the
        // processor to be used on each window. Connect it to the source.
        Window win = new Window(sum, 3);
        Connector.connect(source, win);
        
        // Pull events from the window
        Pullable p = win.getPullableOutput();
        System.out.println("First window: " + p.pull());
        System.out.println("Second window: " + p.pull());
        System.out.println("Third window: " + p.pull());
        ///
    }
}