/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   */
  package javax.faces.model;
  
  /**
   * see Javadoc of <a href="http://java.sun.com/javaee/javaserverfaces/1.2/docs/api/index.html">JSF Specification</a>
   */
  public class ScalarDataModel<E> extends DataModel<E>
  {
      // FIELDS
      private int _rowIndex = -1;
      private E _data;
  
      // CONSTRUCTORS
      public ScalarDataModel()
      {
          super();
      }
  
      public ScalarDataModel(E scalar)
      {
          setWrappedData(scalar);
      }
  
      // METHODS
      @Override
      public int getRowCount()
      {
          return _data != null ? 1 : -1;
      }
  
      @Override
      public E getRowData()
      {
          if (_data == null)
          {
              return null;
          }
          if (!isRowAvailable())
          {
              throw new IllegalArgumentException("row is unavailable");
          }
          return _data;
      }
  
      @Override
      public int getRowIndex()
      {
          return _rowIndex;
      }
  
      @Override
      public Object getWrappedData()
      {
          return _data;
      }
  
      @Override
      public boolean isRowAvailable()
      {
          return _data != null && _rowIndex == 0;
      }
  
      @Override
      public void setRowIndex(int rowIndex)
      {
          if (rowIndex < -1)
          {
              throw new IllegalArgumentException("illegal rowIndex " + rowIndex);
          }
          int oldRowIndex = _rowIndex;
          _rowIndex = rowIndex;
          if (_data != null && oldRowIndex != _rowIndex)
          {
              Object data = isRowAvailable() ? getRowData() : null;
              DataModelEvent event = new DataModelEvent(this, _rowIndex, data);
              DataModelListener[] listeners = getDataModelListeners();
              for (int i = 0; i < listeners.length; i++)
              {
                  listeners[i].rowSelected(event);
              }
          }
      }
 
     @Override
     public void setWrappedData(Object data)
     {
         if (data == null)
         {
             setRowIndex(-1);
             _data = null;
         }
         else
         {
             _data = (E) data;
             _rowIndex = -1;
             setRowIndex(0);
         }
     }
 
 }