FileReader.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 java.io.InputStream;

import ca.uqac.lif.cep.Pullable;
import ca.uqac.lif.cep.UtilityMethods;
import ca.uqac.lif.cep.io.ReadLines;

/**
 * Read an input stream from a text file line by line and show the output.
 * 
 * @author Sylvain Hallé
 * @difficulty Easy
 */
public class FileReader
{
    public static void main(String[] args)
    {
        /* Get an input stream on some resource. Here we read a file
         * that resides with the source code by using the getResourceAsStream()
         * method. (This is standard Java and not specific to BeepBeep.) */
        InputStream stream = FileReader.class.getResourceAsStream("numbers.txt");
        
        /* Give this stream to a LineReader processor. The LineReader
         * reads the lines of a file one by one, and outputs each line
         * as an event (a String object). */
        ReadLines reader = new ReadLines(stream);
        
        /* The addCrlf() method tells the line reader *not* to append a
         * carriage return at the end of each event. There exist situations where
         * this might be useful, but not here. */
        reader.addCrlf(false);
        
        /* Get a reference to the output pullable of the LineReader. */
        Pullable p = reader.getPullableOutput();
        
        /* We exploit the fact that p can be used like an iterator to
         * write the loop as follows: */
        for (Object o : p)
        {
            /* Note that the events produced by the LineReader are *strings*;
             * here, they just happen to be strings that contain numbers. */
            System.out.printf("The event is %s\n", o);
            // Sleep a little so you have time to read!
            UtilityMethods.pause(1000);
        }
    }
}