/**

  * Distribution License:

  * JSword is free software; you can redistribute it and/or modify it under

  * the terms of the GNU Lesser General Public License, version 2.1 or later

  * as published by the Free Software Foundation. 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.

  *

  * The License is available on the internet at:

  *      http://www.gnu.org/copyleft/lgpl.html

  * or by writing to:

  *      Free Software Foundation, Inc.

  *      59 Temple Place - Suite 330

  *      Boston, MA 02111-1307, USA

  *

  * © CrossWire Bible Society, 2005 - 2016

  *

  */

 package org.crosswire.jsword.book.filter;

 import java.util.HashMap;

 import java.util.Locale;

 import java.util.Map;

 import org.crosswire.common.util.PluginUtil;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 /**

  * A simple container for all the known SourceFilters.

  * 

  * @see gnu.lgpl.License The GNU Lesser General Public License for details.

  * @author Joe Walker

  */

 public final class SourceFilterFactory {

     /**

      * Prevent instantiation

      */

     private SourceFilterFactory() {

     }

     /**

      * Find a filter given a lookup string. If lookup is null or the filter is

      * not found then the default filter will be used.

      * 

      * @param lookup the lookup string for the filter

      * @return the matching filter

      */

     public static SourceFilter getFilter(String lookup) {

         SourceFilter reply = filters.get(lookup.toLowerCase(Locale.ENGLISH));

         if (reply == null) {

             reply = deft;

         }

         return reply.clone();

     }

     /**

      * Find a filter given a lookup string

      * 

      * @return the default filter

      */

     public static SourceFilter getDefaultFilter() {

         return deft.clone();

     }

     /**

      * Add to our list of known filters

      * 

      * @param name 

      * @param instance 

      */

     public static void addFilter(String name, SourceFilter instance) {

         filters.put(name.toLowerCase(Locale.ENGLISH), instance);

     }

     /**

      * The lookup table of filters

      */

     private static Map<String, SourceFilter> filters = new HashMap<String, SourceFilter>();

     /**

      * The log stream

      */

     private static final Logger log = LoggerFactory.getLogger(SourceFilterFactory.class);

     /**

      * The lookup table of filters

      */

     private static volatile SourceFilter deft;

     /**

      * Populate the lookup table of filters and the default from the properties

      * file.

      */

     static {

         Map<String, Class<SourceFilter>> map = PluginUtil.getImplementorsMap(SourceFilter.class);

         // the default value

         try {

             Class<SourceFilter> cdeft = map.remove("default");

             deft = cdeft.newInstance();

         } catch (InstantiationException e) {

             log.error("Failed to get default filter, will attempt to use first", e);

         } catch (IllegalAccessException e) {

             log.error("Failed to get default filter, will attempt to use first", e);

         }

         // the lookup table

         SourceFilter instance = null;

         for (Map.Entry<String, Class<SourceFilter>> entry : map.entrySet()) {

             try {

                 Class<SourceFilter> clazz = entry.getValue();

                 instance = clazz.newInstance();

                 addFilter(entry.getKey(), instance);

             } catch (InstantiationException ex) {

                 log.error("Failed to add filter", ex);

             } catch (IllegalAccessException ex) {

                 log.error("Failed to add filter", ex);

             }

         }

         // if the default didn't work then make a stab at an answer

         if (deft == null) {

             deft = instance;

         }

     }

 }