package org.codehaus.plexus.component.discovery;
   
   /*
    * Copyright 2001-2006 Codehaus 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.
   */
  
  import java.io.Reader;
  import java.util.Arrays;
  
  import org.codehaus.plexus.classworlds.realm.ClassRealm;
  import org.codehaus.plexus.component.repository.ComponentDescriptor;
  import org.codehaus.plexus.component.repository.ComponentSetDescriptor;
  import org.codehaus.plexus.component.repository.io.PlexusTools;
  import org.codehaus.plexus.configuration.PlexusConfiguration;
  import org.codehaus.plexus.configuration.PlexusConfigurationException;
  
  public class PlexusXmlComponentDiscoverer extends AbstractResourceBasedComponentDiscoverer {
      public String getComponentDescriptorLocation() {
          return "META-INF/plexus/plexus.xml";
      }
  
      @Override
      protected ComponentSetDescriptor createComponentDescriptors(Reader reader, String source, ClassRealm realm)
              throws PlexusConfigurationException {
          ComponentSetDescriptor componentSetDescriptor = new ComponentSetDescriptor();
  
          PlexusConfiguration configuration = PlexusTools.buildConfiguration(source, reader);
  
          if (configuration != null) {
              PlexusConfiguration[] componentConfigurations =
                      configuration.getChild("components").getChildren("component");
  
              for (PlexusConfiguration componentConfiguration : componentConfigurations) {
                  ComponentDescriptor<?> componentDescriptor;
  
                  try {
                      componentDescriptor = PlexusTools.buildComponentDescriptor(componentConfiguration, realm);
  
                      if (componentDescriptor == null) {
                          continue;
                      }
                  } catch (PlexusConfigurationException e) {
                      throw new PlexusConfigurationException(
                              "Cannot build component descriptor from resource found in:\n"
                                      + Arrays.asList(realm.getURLs()),
                              e);
                  }
  
                  componentDescriptor.setComponentType("plexus");
  
                  componentDescriptor.setComponentSetDescriptor(componentSetDescriptor);
  
                  componentSetDescriptor.addComponentDescriptor(componentDescriptor);
              }
          }
  
          return componentSetDescriptor;
      }
  }