In.java

package jass.engine;
import java.util.*;

/**
   Input unit which contains Sources and does something with them in
   run().  Maintains Vector of Sources. Needs only implementation of run(). 
   @author Kees van den Doel (kvdoel@cs.ubc.ca)
*/

public abstract class In extends Thread implements Sink {
    protected Vector<Source> sourceContainer;

    public In() {
        sourceContainer = new Vector<Source>();
    }
    
    /** add source to Sink.
        @param s Source to add.
        @return object representing Source in Sink (may be null).
    */
    public synchronized Object addSource(Source s) throws SinkIsFullException {
        sourceContainer.addElement(s);
        return null;
    }

    /** Remove Source.
        @param s Source to remove.
    */
    public synchronized void removeSource(Source s) {
        sourceContainer.removeElement(s);
    }

    /** Get array of sources.
        @return array of the Sources, null if there are none.
    */
    public Source [] getSources() {
        return sourceContainer.toArray(new Source[0]);
    }
}