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/***********************************************************************************************************************
 *
 * blueMarine Metadata - open source media workflow
 * Copyright (C) 2007-2011 by Tidalwave s.a.s. (http://www.tidalwave.it)
 *
 ***********************************************************************************************************************
 *
 * 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.
 *
 ***********************************************************************************************************************
 *
 * WWW: http://bluemarine.tidalwave.it
 * SCM: https://kenai.com/hg/bluemarine~metadata-src
 *
 **********************************************************************************************************************/
package it.tidalwave.metadata.spi;

import net.sf.cglib.proxy.Callback;
import it.tidalwave.beans.AbstractEnhancer;
import it.tidalwave.beans.JavaBean;
import it.tidalwave.metadata.spi.impl.MetadataItemAspect;
import java.beans.PropertyChangeListener;
import javax.annotation.Nonnull;

/*******************************************************************************
 * 
 * This factory provides enhanced metadata items that support the JavaBean
 * specification and implement the {@link MetadataItem} interface. The requisites
 * for the source classes are:
 * 
 * 
 * to provide properties by means of getter/setters;
 * to provide an "*Available" property for each property (e.g.
 *     isFooAvailable() for getFoo());
 * 
 * 
 *  * public class ExampleMetadataItem
 *   {
 *     private String name;
 *     private boolean nameAvailable;
 *     
 *     public void setName (final String name)
 *       {
 *         this.name = name;    
 *       }
 *     
 *     public String getName()
 *       {
 *         return name;    
 *       }
 *     
 *     public void setNameAvailable (final boolean nameAvailable)
 *       {
 *         this.nameAvailable = nameAvailable;    
 *       }
 *     
 *     public boolean isNameAvailable()
 *       {
 *         return nameAvailable;    
 *       }
 *   }
 * 
 * 
 * Now, calling:
 * 
 *  * ExampleMetadataItem item = MetadataItemEnhancer.createEnhancedItem(new ExampleMetadataItem()));
 * 
 * 
 * an enhanced item is returned. To use the enhanced features such as the
 * support for {@link PropertyChangeListener}s, you have to use the reflection API
 * or to explicitly cast as in the example below:
 * 
 *  * ((JavaBean)item).addPropertyChangeListener(...);
 * 
 * 
 * In addition to the JavaBean specifications, the enhanced items also supports 
 * these semantics:
 * 
 * 
 * setting a property to a non-null value will force the related 
 *     ***Available() property to true;
 * setting an ***Available() property to false will 
 *     force the related property to null.
 * 
 * 
 * @hidden
 *
 * @author  Fabrizio Giudici
 * @version $Id$
 *
 ******************************************************************************/
public class MetadataItemEnhancer extends AbstractEnhancer
  {
    private final static MetadataItemEnhancer instance = new MetadataItemEnhancer();
    
    /***************************************************************************
     *
     * 
     **************************************************************************/
    private MetadataItemEnhancer()
      {
        super(JavaBean.class);
      }
    
    /***************************************************************************
     *
     * Creates an enhanced item.
     * 
     * @param   bean  the original item
     * @return        the enhanced item
     * 
     **************************************************************************/
    @Nonnull 
    public static  T createEnhancedItem (@Nonnull final T bean, @Nonnull final Object ... arguments)
      {
        return (T)instance.createEnhancedBean(bean, arguments);
      }
    
    /***************************************************************************
     *
     * {@inheritDoc} This method specifies {@link MetadataItemAspect} as the
     * aspect implementation to give to enhanced beans.
     * 
     **************************************************************************/
    @Override
    @Nonnull 
    protected Callback createInterceptor (@Nonnull final Object bean, @Nonnull final Object ... arguments)
      {
        return new MetadataItemAspect(bean, this, arguments);
      }
  }