/**

  * 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.widgets.list;

 import java.util.ArrayList;

 import java.util.List;

 import org.kuali.student.common.ui.client.mvc.Callback;

 import org.kuali.student.common.ui.client.mvc.HasWidgetReadyCallback;

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

 import com.google.gwt.event.dom.client.HasBlurHandlers;

 import com.google.gwt.event.dom.client.HasFocusHandlers;

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

 import com.google.gwt.user.client.ui.Composite;

 import com.google.gwt.user.client.ui.HasName;

 import com.google.gwt.user.client.ui.Widget;

 /**

  * This SelectItemWidget abstracts out the use of selecting an item from a list.

  * Use of this interface will easily allow the underlying widget to be 

  * interchangeable.

  * 

  * @author Kuali Student Team

  *

  */

 public abstract class KSSelectItemWidgetAbstract extends Composite implements HasName, HasFocusHandlers, HasBlurHandlers, HasSelectionChangeHandlers, HasWidgetReadyCallback{

         private ListItems listItems = null;

         private String name;

         private List<Callback<Widget>> widgetReadyCallbacks;

         private boolean initialized = false;

         public ListItems getListItems() {

                 return listItems;

         }

         public <T extends Idable> void setListItems(ListItems listItems) {

                 this.listItems = listItems;

         }        

         public abstract void redraw();

         /**

          * Used to had a selection change handler.

          * 

          * @param selectionHandler

          * @return

          */

     public HandlerRegistration addSelectionChangeHandler(SelectionChangeHandler selectionHandler){

         return addHandler(selectionHandler,SelectionChangeEvent.getType());

     }           

         protected void fireChangeEvent(boolean userInitiated){

             SelectionChangeEvent.fire(this, userInitiated);

         }

         /**

          * Select the item in list represented by the id. For multi-select list

          * any existing selection should remain selected.

          * 

          * @param id

          */        

         public abstract void selectItem(String id);

         /**

          * Remove selection for item represented by id.

          * 

          * @param id

          */

         public abstract void deSelectItem(String id);

         /**

          * List of items that have been selected.

          * 

          * @return

          */

         public abstract List<String> getSelectedItems();

         /**

          * Id of selected item.  If multiple items are selected, this will return the

          * first selected item.

          * 

          * @see com.google.gwt.user.client.ui.HasName#getName()

          */

         public String getSelectedItem(){

             String selectedItem = null;

             List<String> selectedItems = getSelectedItems();

             if (selectedItems != null && selectedItems.size() > 0){

                 selectedItem = selectedItems.get(0);

             }

             return selectedItem;

         }        

     public String getName() {

         return this.name;

     }

     public void setName(String name) {

         this.name = name;         

     }

     /** 

      * This method should be implemented if list supports setting of multiple select. 

      * 

      */

     public void setMultipleSelect(boolean isMultipleSelect){

         throw new UnsupportedOperationException();

     }

     /**

      *  

      * This method should if implemented if list supports multiple select

      *

      */

     public boolean isMultipleSelect(){

         return false;

     }

     /** 

      * This method should be implemented if list supports column sizing. 

      * 

      */

     public void setColumnSize(int col){

         throw new UnsupportedOperationException();

     }

     public abstract void onLoad();

     public abstract void setEnabled(boolean b);

     public abstract boolean isEnabled();

     /**

      * 

      * This method clears the current selection

      *

      */

     public abstract void clear();

     @Override

     public void addWidgetReadyCallback(Callback<Widget> callback) {

         if (widgetReadyCallbacks == null){

             widgetReadyCallbacks = new ArrayList<Callback<Widget>>();

         }

         widgetReadyCallbacks.add(callback);    

    }

     @Override

     public void setInitialized(boolean initialized) {

         this.initialized = initialized;

         if (initialized){

             //Callbacks might need to be moved after a redraw happens

             while (widgetReadyCallbacks != null && widgetReadyCallbacks.size() > 0){

                 Callback<Widget> callback = widgetReadyCallbacks.remove(0);

                 callback.exec(this);

             }            

         }

     }

     @Override

     public boolean isInitialized() {

         return initialized;

     }

 }