/**

  * Copyright 2010 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.osedu.org/licenses/ECL-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.kuali.student.common.ui.client.mvc;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.Collections;

 import java.util.HashMap;

 import java.util.Map;

 import org.kuali.student.common.ui.client.mvc.ModelChangeEvent.Action;

 import org.kuali.student.core.dto.Idable;

 import com.google.gwt.event.shared.HandlerManager;

 import com.google.gwt.event.shared.HandlerRegistration;

 /**

  * Model object used as a container for the model state. Sources ModelChangeEvents used for tracking the model state.

  * 

  * @author Kuali Student Team

  * @param <T>

  *            the type of model object to be contained within the model

  */

 public class CollectionModel<T> implements Model {

     private Map<String, T> data = new HashMap<String, T>();

     private HandlerManager handlers = new HandlerManager(this);

     private T value = null;

     /**

      * Adds an object to the model, and fires a ModelChangeEvent

      * @param object

      */

     public void add(T object) {

         if (object instanceof Idable){

             data.put(((Idable)object).getId(), object);

             handlers.fireEvent(new CollectionModelChangeEvent<T>(Action.ADD, this, object));

         }

     }

         /**

          * Removes the specified model object from the model

          * 

          * @param object

          * @return the object that was removed, or null if not found

          * @deprecated should use new Data structures instead, accessed via getValue, setValue  

          */

     public T remove(T object) {

             if (object instanceof Idable){

                 T result = data.remove(((Idable)object).getId());

                 if (result != null) {

                     handlers.fireEvent(new CollectionModelChangeEvent<T>(Action.REMOVE, this, result));

                 }

                 return result;

             } else {

                 return null;

             }

     }

     /**

      * Adds a ModelChangeHandler that will be invoked for ModelChangeEvents

      * 

      * @param handler

      *            the handler to add

      * @return HandlerRegistration that can be used to unregister the handler later

      */

     @Override

     public HandlerRegistration addModelChangeHandler(ModelChangeHandler handler) {

         return handlers.addHandler(ModelChangeEvent.TYPE, handler);

     }

     /**

      * Returns an unsorted, umodifiable collection of the values contained within the model.

      * 

      * @return an unsorted, umodifiable collection of the values contained within the model.

      */

     public Collection<T> getValues() {

         return Collections.unmodifiableList(new ArrayList<T>(data.values()));

     }

     /**

      * Returns the Model's value

      * Going forward, the Model class should primarily be used with a single DataModel instance for use with the configurable UI framework.

      * @return the Model's value

      */

     public T getValue() {

                 return value;

         }

     /**

      * Sets the Model's value

      * Going forward, the Model class should primarily be used with a single DataModel instance for use with the configurable UI framework.

      * @param value the new value

          */

         public void setValue(T value) {

                 this.value = value;

                 handlers.fireEvent(new CollectionModelChangeEvent<T>(Action.RELOAD, this, value));

         }

 }