package org.codehaus.plexus.classworlds.strategy;

 /*

  * 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.IOException;

 import java.net.URL;

 import java.util.Enumeration;

 import org.codehaus.plexus.classworlds.realm.ClassRealm;

 /**

  * @author Jason van Zyl

  */

 public class ParentFirstStrategy

     extends AbstractStrategy

 {

     public ParentFirstStrategy( ClassRealm realm )

     {

         super( realm );

     }

     public Class<?> loadClass( String name )

         throws ClassNotFoundException

     {

         Class<?> clazz = realm.loadClassFromImport( name );

         if ( clazz == null )

         {

             clazz = realm.loadClassFromParent( name );

             if ( clazz == null )

             {

                 clazz = realm.loadClassFromSelf( name );

                 if ( clazz == null )

                 {

                     throw new ClassNotFoundException( name );

                 }

             }

         }

         return clazz;

     }

     public URL getResource( String name )

     {

         URL resource = realm.loadResourceFromImport( name );

         if ( resource == null )

         {

             resource = realm.loadResourceFromParent( name );

             if ( resource == null )

             {

                 resource = realm.loadResourceFromSelf( name );

             }

         }

         return resource;

     }

     public Enumeration<URL> getResources( String name )

         throws IOException

     {

         Enumeration<URL> imports = realm.loadResourcesFromImport( name );

         Enumeration<URL> parent = realm.loadResourcesFromParent( name );

         Enumeration<URL> self = realm.loadResourcesFromSelf( name );

         return combineResources( imports, parent, self );

     }

 }