001/**
002 * Copyright 2010 The Kuali Foundation Licensed under the
003 * Educational Community License, Version 2.0 (the "License"); you may
004 * not use this file except in compliance with the License. You may
005 * obtain a copy of the License at
006 *
007 * http://www.osedu.org/licenses/ECL-2.0
008 *
009 * Unless required by applicable law or agreed to in writing,
010 * software distributed under the License is distributed on an "AS IS"
011 * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
012 * or implied. See the License for the specific language governing
013 * permissions and limitations under the License.
014 */
015
016package org.kuali.student.common.ui.client.mvc;
017
018import com.google.gwt.event.shared.GwtEvent;
019
020/**
021 * Event that is fired when the model is changed.
022 * 
023 * @author Kuali Student Team
024 * @param <T>
025 */
026public class ModelChangeEvent extends GwtEvent<ModelChangeHandler> {
027    public static final Type<ModelChangeHandler> TYPE = new Type<ModelChangeHandler>();
028
029    /**
030     * The actions that can be performed on a model.
031     * 
032     * @author Kuali Student Team
033     */
034    public enum Action {
035        ADD, REMOVE, UPDATE, RELOAD
036    }
037
038    private final Action action;
039    private final Model source;
040    
041    /**
042     * Constructs a new ModelChangeEvent with an action and a value
043     * 
044     * @param action
045     * @param value
046     */
047    public ModelChangeEvent(Action action, Model source) {
048        this.action = action;
049        this.source = source;
050    }
051
052    @Override
053    protected void dispatch(ModelChangeHandler handler) {
054        handler.onModelChange(this);
055    }
056
057    @Override
058    @SuppressWarnings("unchecked")
059    public Type<ModelChangeHandler> getAssociatedType() {
060        return (Type) TYPE;
061    }
062
063    /**
064     * Returns the action (ADD/UPDATE/REMOVE) associated with the event
065     * 
066     * @return
067     */
068    public Action getAction() {
069        return this.action;
070    }
071
072    /**
073     * Returns the model from which this event originated
074     * 
075     * @return the model from which this event originated
076     */
077    public Model getSource() {
078        return this.source;
079    }
080}