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

 package org.galagosearch.core.index;

 import java.util.ArrayList;

 import org.galagosearch.tupleflow.Parameters;

 import org.galagosearch.tupleflow.Processor;

 import org.galagosearch.core.parse.Document;

 import org.galagosearch.core.parse.Porter2Stemmer;

 import org.galagosearch.core.parse.WordFilter;

 import java.util.HashSet;

 /**

  *

  * @author trevor

  */

 public class DocumentTransformationFactory {

     public static Processor<Document> instance(Parameters parameters, String key) {

         Processor<Document> processor = null;

         if (key.equals("stopper") && parameters.containsKey("stopper")) {

             HashSet<String> stopwords = new HashSet<String>(parameters.stringList("stopper/word"));

             processor = new WordFilter(stopwords);

         }

         if (key.equals("stemmer") && parameters.get("stemmer", "none").equals("porter2")) {

             processor = new Porter2Stemmer();

         }

         return processor;

     }

     public static ArrayList<Processor<Document>> instance(Parameters parameters) {

         ArrayList<Processor<Document>> transformations = new ArrayList<Processor<Document>>();

         String[] transformationNames = {"stopper", "stemmer"};

         for (String name : transformationNames) {

             Processor<Document> transformation = instance(parameters, name);

             if (transformation != null) {

                 transformations.add(transformation);

             }

         }

         return transformations;

     }

 }