package org.jtheque.core.managers.persistence;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.Map;

 /*

  * This file is part of JTheque.

  *

  * JTheque is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, either version 3 of the License.

  *

  * JTheque 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 General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with JTheque.  If not, see <http://www.gnu.org/licenses/>.

  */

 /**

  * Simple HashMap who doesn't support null value.

  *

  * @author Baptiste Wicht

  * @param <K> The type of the key.

  * @param <V> The type of the value.

  */

 final class CacheHashMap<K, V> extends HashMap<K, V> {

     /**

      * Create a new CacheHashMap.

      *

      * @param initialCapacity The initial capacity of the map.

      */

     CacheHashMap(int initialCapacity) {

         super(initialCapacity);

     }

     @Override

     public V put(K key, V value) {

         if (value == null) {

             return null;

         }

         return super.put(key, value);

     }

     @Override

     public void putAll(Map<? extends K, ? extends V> m) {

         super.putAll(m);

         if (containsValue(null)) {

             clearNullValues();

         }

     }

     /**

      * Clear all entries who contains null values.

      */

     private void clearNullValues() {

         Iterator<Map.Entry<K, V>> iterator = entrySet().iterator();

         while (iterator.hasNext()) {

             Map.Entry<K, V> entry = iterator.next();

             if (entry.getValue() == null) {

                 iterator.remove();

             }

         }

     }

 }