// BSD License (http://www.galagosearch.org/license)

 package org.galagosearch.tupleflow.execution;

 import java.util.ArrayList;

 import org.galagosearch.tupleflow.IncompatibleProcessorException;

 import org.galagosearch.tupleflow.Linkage;

 import org.galagosearch.tupleflow.Processor;

 import org.galagosearch.tupleflow.Source;

 import org.galagosearch.tupleflow.Step;

 /**

  *

  * @author trevor

  */

 public class Chain {

     ArrayList<Step> items = new ArrayList();

     public void add(Step stage) throws IncompatibleProcessorException {

         if (items.size() > 0) {

             // is this a ShreddedProcessor?

             Object previousSource = items.get(items.size() - 1);

             ((Source) previousSource).setProcessor(stage);

         }

         items.add(stage);

     }

     public Step getStage() {

         if (items.size() > 0) {

             Step first = items.get(0);

             return first;

         }

         return null;

     }

 }