/**

  * 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;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.Collections;

 import java.util.Iterator;

 import java.util.Set;

 import java.util.TreeSet;

 import org.crosswire.common.util.Filter;

 /**

  * BookSet represents a collection of descriptions about Books which may be

  * subsetted into other BookMetaDataSets. Each set is naturally ordered.

  * 

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

  * @author DM Smith

  */

 public class BookSet extends ArrayList<Book> implements Set<Book> {

     public BookSet() {

     }

     public BookSet(Collection<Book> books) {

         this();

         addAll(books);

     }

     /**

      * Gets the sorted set of all keys which can be used for groupings. These

      * are all the property keys across the BookMetaDatas in this list.

      * 

      * @return the set of all keys which can be used for grouping.

      */

     public Set<String> getGroups() {

         Set<String> results = new TreeSet<String>();

         for (Book book : this) {

             results.addAll(book.getPropertyKeys());

         }

         return results;

     }

     /**

      * Get the sorted set of all values for a particular key. If there is a

      * BookMetaData that does not have a value for that key, then null will be

      * in the set. This can be use to categorize books that don't have that key.

      * For example, "Language" will return all the languages for this

      * BookMetaDataList and null for which the language is unknown.

      * 

      * @param key the property key

      * @return the values for a particular key.

      */

     public Set<Object> getGroup(String key) {

         Set<Object> results = new TreeSet<Object>();

         for (Book book : this) {

             Object property = book.getProperty(key);

             if (property != null) {

                 results.add(property);

             }

         }

         return results;

     }

     public BookSet filter(String key, Object value) {

         return filter(new GroupFilter(key, value));

     }

     /**

      * Get a set of books that satisfy the condition imposed by the filter.

      * 

      * @param filter the condition on which to select books

      * @return the set of matching books

      */

     public BookSet filter(Filter<Book> filter) {

         // create a copy of the list and

         // remove everything that fails the test.

         BookSet listSet = (BookSet) clone();

         Iterator<Book> iter = listSet.iterator();

         while (iter.hasNext()) {

             Book obj = iter.next();

             if (!filter.test(obj)) {

                 iter.remove();

             }

         }

         return listSet;

     }

     /* (non-Javadoc)

      * @see java.util.ArrayList#add(int, java.lang.Object)

      */

     @Override

     public void add(int index, Book element) {

         // ignore the requested index

         add(element);

     }

     /* (non-Javadoc)

      * @see java.util.ArrayList#add(java.lang.Object)

      */

     @Override

     public final boolean add(Book book) {

         // Add the item only if it is not in the list.

         // Add it into the list so that it is in sorted order.

         int pos = Collections.binarySearch(this, book);

         if (pos < 0) {

             super.add(-pos - 1, book);

             return true;

         }

         return false;

     }

     /* (non-Javadoc)

      * @see java.util.ArrayList#addAll(java.util.Collection)

      */

     @Override

     public final boolean addAll(Collection<? extends Book> c) {

         // Might be better to add the list to the end

         // and then sort the list.

         // This can be revisited if the list performs badly.

         boolean added = false;

         for (Book book : c) {

             if (add(book)) {

                 added = true;

             }

         }

         return added;

     }

     /* (non-Javadoc)

      * @see java.util.ArrayList#addAll(int, java.util.Collection)

      */

     @Override

     public final boolean addAll(int index, Collection<? extends Book> c) {

         // Ignore the index

         return addAll(c);

     }

     /* (non-Javadoc)

      * @see java.util.ArrayList#set(int, java.lang.Object)

      */

     @Override

     public Book set(int index, Book element) {

         // remove the item at the index (keep it to return it),

         // then insert the item into the sorted list.

         Book item = remove(index);

         add(element);

         return item;

     }

     /**

      * GroupFilter does the SQL traditional group by.

      */

     private static final class GroupFilter implements Filter<Book> {

         GroupFilter(String aKey, Object aValue) {

             key = aKey;

             value = aValue;

         }

         public boolean test(Book book) {

             String property = book.getProperty(key);

             return property != null && property.equals(value);

         }

         private String key;

         private Object value;

     }

     /**

      * Serialization ID

      */

     private static final long serialVersionUID = 3258688806185154867L;

 }