SimpleFunction.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.Pullable;
import ca.uqac.lif.cep.functions.ApplyFunction;
import ca.uqac.lif.cep.tmf.QueueSource;
import ca.uqac.lif.cep.util.Booleans;

/**
 * Use the {@link ca.uqac.lif.cep.functions.ApplyFunction FunctionProcessor}
 * to apply a function to each input event. Here, we apply the negation to
 * every Boolean event. This can be represented grahpically as follows:
 * <p>
 * <img src="./doc-files/basic/SimpleFunction.png" alt="Processor graph">
 * <p>
 * For an input stream with the values <tt>false</tt>, <tt>true</tt>, <tt>true</tt>,
 * <tt>false</tt>, <tt>true</tt>, the expected output should be:
 * <pre>
 * The event is: true
 * The event is: false
 * The event is: false
 * The event is: true
 * The event is: false
 * </pre>
 * @author Sylvain Hallé
 * @difficulty Easy
 */
public class SimpleFunction
{
    /*
     * In this example, we apply the Negation function to a trace of
     * Boolean values.
     */
    public static void main (String[] args)
    {
        ///
        QueueSource source = new QueueSource();
        source.setEvents(false, true, true, false, true);
        ApplyFunction not = new ApplyFunction(Booleans.not);
        Connector.connect(source, not);
        Pullable p = not.getPullableOutput();
        for (int i = 0; i < 5; i++)
        {
            boolean x = (Boolean) p.pull();
            System.out.println("The event is: " + x);
        }
        ///
    }
}