/*

  * $Id: ResourcesFactory.java 349025 2005-11-25 21:09:54Z niallp $

  * $Revision: 349025 $

  * $Date: 2005-11-25 21:09:54 +0000 (Fri, 25 Nov 2005) $

  *

  * ====================================================================

  *

  *  Copyright 2003-2005 The Apache Software Foundation

  *

  *  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.apache.commons.resources;

 import java.io.Serializable;

 /**

  * <a>A {@link org.apache.commons.resources.ResourcesFactory} 

  * is a factory pattern interface for a

  * class that can create {@link org.apache.commons.resources.Resources} 

  * instances based on a logical

  * name that is passed to the factory.  Repeated requests to return a

  * {@link org.apache.commons.resources.Resources} instance with the same 

  * name should return the same

  * {@link org.apache.commons.resources.Resources} instance each time.</p>

  *

  * <p>Implementations of {@link org.apache.commons.resources.ResourcesFactory} 

  * <strong>MUST</strong>

  * include a zero-arguments constructor so that instances of the factory

  * can be dynamically created.  Therefore, configuration information

  * above and beyond the configuration String will generally be specified

  * via JavaBeans property setters on the 

  * {@link org.apache.commons.resources.ResourcesFactory}

  * implementation class.</p>

  *

  * @see org.apache.commons.resources.impl.ResourcesFactoryBase

  * @see org.apache.commons.resources.impl.JDBCResourcesFactory

  * @see org.apache.commons.resources.impl.PropertyResourcesFactory

  * @see org.apache.commons.resources.impl.ResourceBundleResourcesFactory

  * @see org.apache.commons.resources.impl.WebappResourcesFactoryBase

  * @see org.apache.commons.resources.impl.WebappPropertyResourcesFactory

  * @see org.apache.commons.resources.impl.WebappXMLResourcesFactory

  * @see org.apache.commons.resources.impl.XMLResourcesFactory

  */

 public interface ResourcesFactory extends Serializable {

     // ------------------------------------------------------------- Properties

     /**

      * <p>Return the <code>returnNull</code> property value that will be

      * configured on {@link org.apache.commons.resources.Resources} 

      * instances created by this factory.</p>

      * @return 'true' if null is returned for invalid key values.

      */

     public boolean isReturnNull();

     /**

      * <p>Set the <code>returnNull</code> property value that will be configured on 

      * {@link org.apache.commons.resources.Resources} instances created by this 

      * factory.</p>

      *

      * @param returnNull The new value to delegate

      */

     public void setReturnNull(boolean returnNull);

     // --------------------------------------------------------- Public Methods

     /**

      * <p>Create (if necessary) and return a 

      * {@link org.apache.commons.resources.Resources} instance

      * for the specified logical name, with a default configuration.</p>

      *

      * @param name Logical name of the 

      * {@link org.apache.commons.resources.Resources} instance to

      *  be returned

      * @return The resources instance.

      *

      * @exception ResourcesException if a 

      * {@link org.apache.commons.resources.Resources} instance

      *  of the specified logical name cannot be returned.

      */

     public Resources getResources(String name);

     /**

      * <p>Create (if necessary) and return a 

      * {@link org.apache.commons.resources.Resources} instance

      * for the specified logical name, with a configuration based on

      * the specified configuration String.</p>

      *

      * @param name Logical name of the 

      * {@link org.apache.commons.resources.Resources} instance to be returned

      * @param config Configuration string for this resource (meaning

      *  is dependent upon the {@link org.apache.commons.resources.ResourcesFactory} 

      * implementation being utilized), or <code>null</code> for the default

      *  configuration

      * @return The resources.

      *

      * @exception ResourcesException if a 

      * {@link org.apache.commons.resources.Resources} instance

      *  of the specified logical name cannot be returned.

      */

     public Resources getResources(String name, String config);

     /**

      * <p>Release any internal references to 

      * {@link org.apache.commons.resources.Resources} instances

      * that have been returned previously, after calling the

      * <code>destroy()</code> method of each such instance.</p>

      *

      * @exception ResourcesException if an error occurs while releasing

      */

     public void release();

 }