PipingUnaryIncorrect.java

/*
    BeepBeep, an event stream processor
    Copyright (C) 2008-2016 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.Doubler;
import ca.uqac.lif.cep.Pullable;
import ca.uqac.lif.cep.tmf.QueueSource;

/**
 * Pipe processors together using the {@link ca.uqac.lif.cep.Connector Connector}
 * object. The chain of processors in this example can be represented
 * graphically as:
 * <p>
 * <img src="./doc-files/basic/PipingUnary.png" alt="Processor graph">
 * <p>
 * This example differs from {@link PipingUnary} in that we call {@code pull}
 * on the source, which interferes with the proper sequencing of events.
 * @see PipingUnary
 * @author Sylvain Hallé
 * @difficulty Easy
 */
public class PipingUnaryIncorrect
{
    public static void main (String[] args)
    {
        // Create a source of arbitrary numbers
        QueueSource source = new QueueSource();
        source.setEvents(1, 2, 3, 4, 5, 6);
        
        /* Create an instance of the Doubler processor (which is defined just
         * below in this file. */
        Doubler doubler = new Doubler();
        
        /* We now want to connect the output of source to the input of doubler.
         * This connection is done by using static method connect() of the
         * Connector object. Here, source has only one output stream, and
         * doubler has only one input stream. Therefore, we can simply call
         * connect() by giving the "upstream" processor first, and the
         * "downstream" processor second. The Connector will know that it needs
         * to connect the (only) output of source to the (only) input of
         * doubler. */
        Connector.connect(source, doubler);
        
        /* Let us now print what we receive by pulling on the output of
         * doubler. */
        ///
        Pullable p = doubler.getPullableOutput();
        System.out.println("The event is: " + p.pull());
        System.out.println("The event is: " + p.pull());
        Pullable p2 = source.getPullableOutput();
        System.out.println("The event is: " + p2.pull());
        System.out.println("The event is: " + p.pull());
        ///
    }
}