/* ***************************************************************************
    * Copyright (c) 2008 Brabenetz Harald, Austria.
    *
    * Licensed 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.settings4j.connector;
  
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.settings4j.Connector;
  import org.settings4j.ContentResolver;
  import org.settings4j.ObjectResolver;
  
  /**
   * Wrap a Connector and caches all Values.
   * <p>
   * This wrapper will be used if you add in your settings4j.xml the cached="true" Attribute to the Connector TAG.
   * 
   * @author Harald.Brabenetz
   *
   */
  public class CachedConnectorWrapper implements Connector {
  
      private final Connector targetConnector;
  
      private final Map<String, String> cachedStrings = Collections.synchronizedMap(new HashMap<String, String>());
      private final Map<String, byte[]> cachedContents = Collections.synchronizedMap(new HashMap<String, byte[]>());
      private final Map<String, Object> cachedObjects = Collections.synchronizedMap(new HashMap<String, Object>());
  
  
      /**
       * @param targetConnector The connector to wrap.
       */
      public CachedConnectorWrapper(final Connector targetConnector) {
          super();
          this.targetConnector = targetConnector;
      }
  
      /** {@inheritDoc} */
      public byte[] getContent(final String key) {
          byte[] result = this.cachedContents.get(key);
          if (result != null) {
              return result;
          }
  
          result = this.targetConnector.getContent(key);
  
          if (result != null) {
              this.cachedContents.put(key, result);
          }
          return result;
      }
  
      /** {@inheritDoc} */
      public Object getObject(final String key) {
          Object result = this.cachedObjects.get(key);
          if (result != null) {
              return result;
          }
  
          result = this.targetConnector.getObject(key);
  
          if (result != null) {
              this.cachedObjects.put(key, result);
          }
          return result;
      }
  
      /** {@inheritDoc} */
      public String getString(final String key) {
          String result = this.cachedStrings.get(key);
          if (result != null) {
              return result;
          }
  
          result = this.targetConnector.getString(key);
  
          if (result != null) {
              this.cachedStrings.put(key, result);
          }
          return result;
      }
  
      /**
       * @param key the key to clear from all caches.
      */
     public void clearCachedValue(final String key) {
         this.cachedStrings.remove(key);
         this.cachedContents.remove(key);
         this.cachedObjects.remove(key);
     }
 
     /*
      * Delegating Methodes: 
      */
 
     /** {@inheritDoc} */
     public void addConnector(final Connector connector) {
         this.targetConnector.addConnector(connector);
     }
 
     /** {@inheritDoc} */
     public void setContentResolver(final ContentResolver contentResolver) {
         this.targetConnector.setContentResolver(contentResolver);
     }
 
     /** {@inheritDoc} */
     public void setObjectResolver(final ObjectResolver objectResolver) {
         this.targetConnector.setObjectResolver(objectResolver);
     }
 
     /** {@inheritDoc} */
     public void init() {
         this.targetConnector.init();
     }
 
     /** {@inheritDoc} */
     public String getName() {
         return this.targetConnector.getName();
     }
 
     /** {@inheritDoc} */
     public void setName(final String name) {
         this.targetConnector.setName(name);
     }
 
 }