/*
    * Copyright 2007 Joachim Grueneis
    *
    * 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.exolab.castor.xml.util.resolvers;
  
  import java.util.HashMap;
  import java.util.Map;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.exolab.castor.mapping.MappingLoader;
  import org.exolab.castor.xml.ResolverException;
  import org.exolab.castor.xml.XMLClassDescriptor;
  import org.exolab.castor.xml.util.ResolverStrategy;
  
  /**
   * How to sought a descriptor for a class in a specified mapping loader.
   * 
   * @author <a href="mailto:jgrueneis AT gmail DOT com">Joachim Grueneis</a>
   * @author <a href="mailto:stevendolg AT gxm DOT at">Steven Dolg</a>
   * @version $Revision$ $Date$
   * @since 1.2
   */
  public class ByMappingLoader extends AbstractResolverClassCommand {
    private static final Log LOG = LogFactory.getLog(ByMappingLoader.class);
  
    /**
     * No specific stuff needed.
     */
    public ByMappingLoader() {
      super();
    }
  
    /**
     * If a mapping loader is set in the configuration the descriptor for the given class / className
     * is taken from the mapping loader and put into the cache. <br>
     * {@inheritDoc}
     */
    protected Map internalResolve(final String className, final ClassLoader classLoader,
        final Map properties) throws ResolverException {
  
      MappingLoader mappingLoader =
          (MappingLoader) properties.get(ResolverStrategy.PROPERTY_MAPPING_LOADER);
      HashMap results = new HashMap();
      if (mappingLoader == null) {
        LOG.debug("No mapping loader specified");
        return results;
      }
  
      XMLClassDescriptor descriptor = (XMLClassDescriptor) mappingLoader.getDescriptor(className);
      if (descriptor != null) {
        if (LOG.isDebugEnabled()) {
          LOG.debug("Found descriptor: " + descriptor);
        }
        results.put(className, descriptor);
      }
      return results;
    }
  }