/*

  * 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.web;

 import java.util.List;

 import org.apache.commons.configuration.AbstractConfiguration;

 import org.apache.commons.configuration.PropertyConverter;

 /**

  * <p>

  * An abstract base class for all web configurations.

  * </p>

  * <p>

  * This class implements common functionality used by all web based

  * configurations. E.g. some methods are not supported by configurations of this

  * type, so they throw a <code>UnsupportedOperationException</code> exception.

  * </p>

  *

  * @author Oliver Heger

  * @version $Id: BaseWebConfiguration.java 515306 2007-03-06 21:15:00Z oheger $

  * @since 1.2

  */

 abstract class BaseWebConfiguration extends AbstractConfiguration

 {

     /**

      * Checks if this configuration is empty. This implementation makes use of

      * the <code>getKeys()</code> method (which must be defined by concrete

      * sub classes) to find out whether properties exist.

      *

      * @return a flag whether this configuration is empty

      */

     public boolean isEmpty()

     {

         return !getKeys().hasNext();

     }

     /**

      * Checks whether the specified key is stored in this configuration.

      *

      * @param key the key

      * @return a flag whether this key exists in this configuration

      */

     public boolean containsKey(String key)

     {

         return getProperty(key) != null;

     }

     /**

      * Removes the property with the given key. <strong>This operation is not

      * supported and will throw an UnsupportedOperationException.</strong>

      *

      * @param key the key of the property to be removed

      * @throws UnsupportedOperationException because this operation is not

      * allowed

      */

     public void clearProperty(String key)

     {

         throw new UnsupportedOperationException("Read only configuration");

     }

     /**

      * Adds a property to this configuration. <strong>This operation is not

      * supported and will throw an UnsupportedOperationException.</strong>

      *

      * @param key the key of the property

      * @param obj the value to be added

      * @throws UnsupportedOperationException because this operation is not

      * allowed

      */

     protected void addPropertyDirect(String key, Object obj)

     {

         throw new UnsupportedOperationException("Read only configuration");

     }

     /**

      * Takes care of list delimiters in property values. This method checks if

      * delimiter parsing is enabled and the passed in value contains a delimiter

      * character. If this is the case, a split operation is performed.

      *

      * @param value the property value to be examined

      * @return the processed value

      */

     protected Object handleDelimiters(Object value)

     {

         if (!isDelimiterParsingDisabled() && value instanceof String)

         {

             List list = PropertyConverter.split((String) value,

                     getListDelimiter());

             value = list.size() > 1 ? list : list.get(0);

         }

         return value;

     }

 }