/*

  * Copyright 2006-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.core.api.resourceloader;

 import java.util.List;

 import javax.xml.namespace.QName;

 import org.kuali.rice.core.api.reflect.ObjectDefinition;

 /**

  * This is a description of what this class does - ewestfal don't forget to fill this in.

  *

  * @author Kuali Rice Team (rice.collab@kuali.org)

  *

  */

 class ParentChildResourceLoader implements ResourceLoader {

     private final ResourceLoader parent;

     private final ResourceLoader child;

     private QName name;

     ParentChildResourceLoader(ResourceLoader parent, ResourceLoader child) {

             if (parent == null) {

                     throw new IllegalArgumentException("parent resource loader was null");

             }

             if (child == null) {

                     throw new IllegalArgumentException("child resource loader was null");

             }

             this.parent = parent;

             this.child = child;

             this.name = new QName(child.getName().toString() + " to parent " + parent.getName().toString());

     }

         @Override

         public <T> T getObject(ObjectDefinition definition) {

                 T object = child.<T>getObject(definition);

             if (object == null) {

                     object = parent.<T>getObject(definition);

             }

             return object;

         }

         @Override

         public <T> T getService(QName qname) {

                 T service = child.<T>getService(qname);

                 if (service == null) {

                         service = parent.<T>getService(qname);

                 }

                 return service;

     }

         /**

          * "Starts" this resource loader.  When started, this method will simply

          * invoke start on the child resource loader.  It's assumed that the

          * parent will be started from it's context.

          * 

          * @see org.kuali.rice.core.api.lifecycle.Lifecycle#start()

          */

         @Override

     public void start() throws Exception {

                 if (!child.isStarted()) {

                         child.start();

                 }

         }

         /**

          * Just stopes the internal child resource loader.

          * 

          * @see org.kuali.rice.core.api.lifecycle.Lifecycle#stop()

          */

         @Override

     public void stop() throws Exception {

             if (child.isStarted()) {

                     child.stop();

             }

     }

         @Override

     public void addResourceLoader(ResourceLoader resourceLoader) {

             this.child.addResourceLoader(resourceLoader);

     }

         @Override

     public void addResourceLoaderFirst(ResourceLoader resourceLoader) {

             this.child.addResourceLoaderFirst(resourceLoader);

     }

         @Override

     public ResourceLoader getResourceLoader(QName name) {

             ResourceLoader resourceLoader = this.child.getResourceLoader(name);

             if (resourceLoader == null && parent != null) {

                     return parent.getResourceLoader(name);

             } else {

                     return resourceLoader;

             }

     }

         @Override

     public List<QName> getResourceLoaderNames() {

                 return this.child.getResourceLoaderNames();

     }

         @Override

     public List<ResourceLoader> getResourceLoaders() {

                 return this.child.getResourceLoaders();

     }

         @Override

     public void removeResourceLoader(QName name) {

                 this.child.removeResourceLoader(name);

     }

         /**

          * This overridden method ...

          * 

          * @see org.kuali.rice.core.api.lifecycle.Lifecycle#isStarted()

          */

         @Override

         public boolean isStarted() {

                 // TODO ewestfal - THIS METHOD NEEDS JAVADOCS

                 return false;

         }

         @Override

         public void setName(QName name) {

                 this.name = name;

         }

         @Override

         public QName getName() {

                 return this.name;

         }

         /**

          * This overridden method ...

          * 

          * @see org.kuali.rice.core.api.resourceloader.ResourceLoader#getContents(java.lang.String, boolean)

          */

         @Override

         public String getContents(String indent, boolean servicePerLine) {

                 StringBuilder contents = new StringBuilder();

                 contents.append(parent.getContents(indent, servicePerLine)).append("\n");

                 contents.append(child.getContents(indent, servicePerLine));

                 return contents.toString();

         }

 }