package org.codehaus.plexus.component.configurator.converters.special;
   
   import org.codehaus.classworlds.ClassRealmAdapter;
   import org.codehaus.classworlds.ClassRealmReverseAdapter;
   import org.codehaus.plexus.classworlds.realm.ClassRealm;
   import org.codehaus.plexus.component.configurator.ComponentConfigurationException;
   import org.codehaus.plexus.component.configurator.ConfigurationListener;
   import org.codehaus.plexus.component.configurator.converters.AbstractConfigurationConverter;
   import org.codehaus.plexus.component.configurator.converters.ConfigurationConverter;
  import org.codehaus.plexus.component.configurator.converters.lookup.ConverterLookup;
  import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluator;
  import org.codehaus.plexus.configuration.PlexusConfiguration;
  
  /**
   * ConfigurationConverter to set up ClassRealm component fields.
   *
   * @author <a href="mailto:kenney@neonics.com">Kenney Westerhof</a>
   */
  public class ClassRealmConverter extends AbstractConfigurationConverter {
      public static final String ROLE = ConfigurationConverter.class.getName();
  
      private ClassRealm classRealm;
  
      /**
       * Constructs this ClassRealmConverter with the given ClassRealm.
       * If there's a way to automatically configure this component
       * using the current classrealm, this method can go away.
       *
       * @param classRealm {@link ClassRealm}.
       */
      public ClassRealmConverter(ClassRealm classRealm) {
          setClassRealm(classRealm);
      }
  
      @Deprecated
      public ClassRealmConverter(final org.codehaus.classworlds.ClassRealm classRealm) {
          setClassRealm(classRealm);
      }
  
      public void setClassRealm(final ClassRealm classRealm) {
          this.classRealm = classRealm;
      }
  
      @Deprecated
      public void setClassRealm(final org.codehaus.classworlds.ClassRealm classRealm) {
          if (classRealm.getClassLoader() instanceof ClassRealm) {
              setClassRealm((ClassRealm) classRealm.getClassLoader());
          } else {
              setClassRealm(ClassRealmReverseAdapter.getInstance(classRealm));
          }
      }
  
      public boolean canConvert(Class type) {
          // backwards compatibility for old ClassWorld fields
          return org.codehaus.classworlds.ClassRealm.class.isAssignableFrom(type)
                  || ClassRealm.class.isAssignableFrom(type);
      }
  
      public Object fromConfiguration(
              ConverterLookup converterLookup,
              PlexusConfiguration configuration,
              Class type,
              Class baseType,
              ClassLoader classLoader,
              ExpressionEvaluator expressionEvaluator,
              ConfigurationListener listener)
              throws ComponentConfigurationException {
          Object retValue = fromExpression(configuration, expressionEvaluator, type);
  
          if (retValue == null) {
              retValue = classRealm;
          }
  
          // backwards compatibility for old ClassWorld fields
          if (retValue instanceof ClassRealm && org.codehaus.classworlds.ClassRealm.class.isAssignableFrom(type)) {
              retValue = ClassRealmAdapter.getInstance((ClassRealm) retValue);
          }
  
          return retValue;
      }
  }