/*

  * Licensed to the Apache Software Foundation (ASF) under one or more

  * contributor license agreements.  See the NOTICE file distributed with

  * this work for additional information regarding copyright ownership.

  * The ASF licenses this file to You under the Apache License, Version 2.0

  * (the "License"); you may not use this file except in compliance with

  * the License.  You may obtain a copy of the License at

  *

  *  http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.any23.extractor;

 import org.apache.any23.configuration.DefaultConfiguration;

 import org.apache.any23.extractor.csv.CSVExtractor;

 import org.apache.any23.extractor.html.AdrExtractor;

 import org.apache.any23.extractor.html.GeoExtractor;

 import org.apache.any23.extractor.html.HCalendarExtractor;

 import org.apache.any23.extractor.html.HCardExtractor;

 import org.apache.any23.extractor.html.HListingExtractor;

 import org.apache.any23.extractor.html.HRecipeExtractor;

 import org.apache.any23.extractor.html.HResumeExtractor;

 import org.apache.any23.extractor.html.HReviewExtractor;

 import org.apache.any23.extractor.html.HTMLMetaExtractor;

 import org.apache.any23.extractor.html.HeadLinkExtractor;

 import org.apache.any23.extractor.html.ICBMExtractor;

 import org.apache.any23.extractor.html.LicenseExtractor;

 import org.apache.any23.extractor.html.SpeciesExtractor;

 import org.apache.any23.extractor.html.TitleExtractor;

 import org.apache.any23.extractor.html.TurtleHTMLExtractor;

 import org.apache.any23.extractor.html.XFNExtractor;

 import org.apache.any23.extractor.microdata.MicrodataExtractor;

 import org.apache.any23.extractor.rdf.NQuadsExtractor;

 import org.apache.any23.extractor.rdf.NTriplesExtractor;

 import org.apache.any23.extractor.rdf.RDFXMLExtractor;

 import org.apache.any23.extractor.rdf.TriXExtractor;

 import org.apache.any23.extractor.rdf.TurtleExtractor;

 import org.apache.any23.extractor.rdfa.RDFa11Extractor;

 import org.apache.any23.extractor.rdfa.RDFaExtractor;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.HashMap;

 import java.util.List;

 import java.util.Map;

 /**

  *  Singleton class acting as a register for all the various

  *  {@link Extractor}.

  */

 public class ExtractorRegistry {

     /**

      * The instance.

      */

     private static ExtractorRegistry instance = null;

     /**

      * maps containing the related {@link ExtractorFactory} for each

      * registered {@link Extractor}.

      */

     private Map<String, ExtractorFactory<?>> factories = new HashMap<String, ExtractorFactory<?>>();

     /**

      * @return returns the {@link ExtractorRegistry} instance.

      */

     public static ExtractorRegistry getInstance() {

         // Thread-safe

         synchronized (ExtractorRegistry.class) {

             final DefaultConfiguration conf = DefaultConfiguration.singleton();

             if (instance == null) {

                 instance = new ExtractorRegistry();

                 instance.register(RDFXMLExtractor.factory);

                 instance.register(TurtleExtractor.factory);

                 instance.register(NTriplesExtractor.factory);

                 instance.register(NQuadsExtractor.factory);

                 instance.register(TriXExtractor.factory);

                 if(conf.getFlagProperty("any23.extraction.rdfa.programmatic")) {

                     instance.register(RDFa11Extractor.factory);

                 } else {

                     instance.register(RDFaExtractor.factory);

                 }

                 instance.register(HeadLinkExtractor.factory);

                 instance.register(LicenseExtractor.factory);

                 instance.register(TitleExtractor.factory);

                 instance.register(XFNExtractor.factory);

                 instance.register(ICBMExtractor.factory);

                 instance.register(AdrExtractor.factory);

                 instance.register(GeoExtractor.factory);

                 instance.register(HCalendarExtractor.factory);

                 instance.register(HCardExtractor.factory);

                 instance.register(HListingExtractor.factory);

                 instance.register(HResumeExtractor.factory);

                 instance.register(HReviewExtractor.factory);

                 instance.register(HRecipeExtractor.factory);

                 instance.register(SpeciesExtractor.factory);

                 instance.register(TurtleHTMLExtractor.factory);

                 instance.register(MicrodataExtractor.factory);

                 instance.register(CSVExtractor.factory);

                 if(conf.getFlagProperty("any23.extraction.head.meta")) {

                     instance.register(HTMLMetaExtractor.factory);

                 }

             }

         }

         return instance;

     }

     /**

      * Registers an {@link ExtractorFactory}.

      *

      * @param factory

      * @throws IllegalArgumentException if trying to register a {@link ExtractorFactory}

      *         with a that already exists in the registry.

      */

     public void register(ExtractorFactory<?> factory) {

         if (factories.containsKey(factory.getExtractorName())) {

             throw new IllegalArgumentException(String.format("Extractor name clash: %s",

                     factory.getExtractorName()));

         }

         factories.put(factory.getExtractorName(), factory);

     }

     /**

      *

      * Retrieves a {@link ExtractorFactory} given its name

      *

      * @param name of the desired factory

      * @return the {@link ExtractorFactory} associated to the provided name

      * @throws IllegalArgumentException if there is not a

      * {@link ExtractorFactory} associated to the provided name.

      */

     public ExtractorFactory<?> getFactory(String name) {

         if (!factories.containsKey(name)) {

             throw new IllegalArgumentException("Unregistered extractor name: " + name);

         }

         return factories.get(name);

     }

     /**

      * @return an {@link ExtractorGroup} with all the registered

      * {@link Extractor}.

      */

     public ExtractorGroup getExtractorGroup() {

         return getExtractorGroup(getAllNames());

     }

     /**

      * Returns an {@link ExtractorGroup} containing the

      * {@link ExtractorFactory} mathing the names provided as input.

      * @param names a {@link java.util.List} containing the names of the desired {@link ExtractorFactory}.

      * @return the extraction group.

      */

     public ExtractorGroup getExtractorGroup(List<String> names) {

         List<ExtractorFactory<?>> members = new ArrayList<ExtractorFactory<?>>(names.size());

         for (String name : names) {

             members.add(getFactory(name));

         }

         return new ExtractorGroup(members);

     }

     /**

      * 

      * @param name of the {@link ExtractorFactory}

      * @return <code>true</code> if is there a {@link ExtractorFactory}

      * associated to the provided name.

      */

     public boolean isRegisteredName(String name) {

         return factories.containsKey(name);

     }

     /**

      * Returns the names of all registered extractors, sorted alphabetically.

      */

     public List<String> getAllNames() {

         List<String> result = new ArrayList<String>(factories.keySet());

         Collections.sort(result);

         return result;

     }

 }