/*

  * 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.commons.configuration;

 import java.util.ArrayList;

 import java.util.Iterator;

 import java.util.List;

 import java.util.Map;

 import org.apache.commons.collections.map.LinkedMap;

 /**

  * Basic configuration classe. Stores the configuration data but does not

  * provide any load or save functions. If you want to load your Configuration

  * from a file use PropertiesConfiguration or XmlConfiguration.

  *

  * This class extends normal Java properties by adding the possibility

  * to use the same key many times concatenating the value strings

  * instead of overwriting them.

  *

  * @author <a href="mailto:stefano@apache.org">Stefano Mazzocchi</a>

  * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>

  * @author <a href="mailto:daveb@miceda-data">Dave Bryson</a>

  * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>

  * @author <a href="mailto:leon@opticode.co.za">Leon Messerschmidt</a>

  * @author <a href="mailto:kjohnson@transparent.com">Kent Johnson</a>

  * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>

  * @author <a href="mailto:ipriha@surfeu.fi">Ilkka Priha</a>

  * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>

  * @author <a href="mailto:mpoeschl@marmot.at">Martin Poeschl</a>

  * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>

  * @author <a href="mailto:ksh@scand.com">Konstantin Shaposhnikov</a>

  * @author <a href="mailto:oliver.heger@t-online.de">Oliver Heger</a>

  * @version $Id: BaseConfiguration.java 439648 2006-09-02 20:42:10Z oheger $

  */

 public class BaseConfiguration extends AbstractConfiguration implements Cloneable

 {

     /** stores the configuration key-value pairs */

     private Map store = new LinkedMap();

     /**

      * Adds a key/value pair to the map.  This routine does no magic morphing.

      * It ensures the keylist is maintained

      *

      * @param key key to use for mapping

      * @param value object to store

      */

     protected void addPropertyDirect(String key, Object value)

     {

         Object previousValue = getProperty(key);

         if (previousValue == null)

         {

             store.put(key, value);

         }

         else if (previousValue instanceof List)

         {

             // the value is added to the existing list

             ((List) previousValue).add(value);

         }

         else

         {

             // the previous value is replaced by a list containing the previous value and the new value

             List list = new ArrayList();

             list.add(previousValue);

             list.add(value);

             store.put(key, list);

         }

     }

     /**

      * Read property from underlying map.

      *

      * @param key key to use for mapping

      *

      * @return object associated with the given configuration key.

      */

     public Object getProperty(String key)

     {

         return store.get(key);

     }

     /**

      * Check if the configuration is empty

      *

      * @return <code>true</code> if Configuration is empty,

      * <code>false</code> otherwise.

      */

     public boolean isEmpty()

     {

         return store.isEmpty();

     }

     /**

      * check if the configuration contains the key

      *

      * @param key the configuration key

      *

      * @return <code>true</code> if Configuration contain given key,

      * <code>false</code> otherwise.

      */

     public boolean containsKey(String key)

     {

         return store.containsKey(key);

     }

     /**

      * Clear a property in the configuration.

      *

      * @param key the key to remove along with corresponding value.

      */

     protected void clearPropertyDirect(String key)

     {

         if (containsKey(key))

         {

             store.remove(key);

         }

     }

     /**

      * {@inheritDoc}

      */

     public void clear()

     {

         fireEvent(EVENT_CLEAR, null, null, true);

         store.clear();

         fireEvent(EVENT_CLEAR, null, null, false);

     }

     /**

      * Get the list of the keys contained in the configuration

      * repository.

      *

      * @return An Iterator.

      */

     public Iterator getKeys()

     {

         return store.keySet().iterator();

     }

     /**

      * Creates a copy of this object. This implementation will create a deep

      * clone, i.e. the map that stores the properties is cloned, too. So changes

      * performed at the copy won't affect the original and vice versa.

      *

      * @return the copy

      * @since 1.3

      */

     public Object clone()

     {

         try

         {

             BaseConfiguration copy = (BaseConfiguration) super.clone();

             copy.store = (Map) ConfigurationUtils.clone(store);

             copy.clearConfigurationListeners();

             return copy;

         }

         catch (CloneNotSupportedException cex)

         {

             // should not happen

             throw new ConfigurationRuntimeException(cex);

         }

     }

 }