/*
    * 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 org.apache.myfaces.orchestra.dynaForm.jsf.guiBuilder.impl.jsf;
  
  import javax.faces.component.StateHolder;
  import javax.faces.component.UIComponentBase;
  import javax.faces.context.FacesContext;
  import javax.faces.el.EvaluationException;
  import javax.faces.el.MethodBinding;
  import javax.faces.el.PropertyNotFoundException;
  import javax.faces.el.ValueBinding;
  import javax.faces.model.SelectItem;
  import java.util.Collection;
  
  /**
   * wraps a datasource and presents it as selectItem list
   */
  public class ValueBindingDataSourceAdapter extends ValueBinding implements StateHolder
  {
      private MethodBinding mbValues;
      private MethodBinding mbLabels;
  
      private boolean _transient = false;
  
      public ValueBindingDataSourceAdapter()
      {
      }
  
      public ValueBindingDataSourceAdapter(MethodBinding mbValues, MethodBinding mbLabels)
      {
          this.mbValues = mbValues;
          this.mbLabels = mbLabels;
      }
  
  
      @Override
      public Class<?> getType(FacesContext facesContext) throws EvaluationException, PropertyNotFoundException
      {
          return SelectItem[].class;
      }
  
      @Override
      public Object getValue(FacesContext facesContext) throws EvaluationException, PropertyNotFoundException
      {
          Object valueList = mbValues.invoke(facesContext, new Object[]{null});
          if (valueList == null)
          {
              return null;
          }
  
          if (valueList instanceof Collection)
          {
              Collection<?> valueCollection = (Collection<?>) valueList;
  
              SelectItem[] selectItems = new SelectItem[valueCollection.size()];
  
              int i = -1;
              for (Object value : valueCollection)
              {
                  i++;
  
                  String label = (String) mbLabels.invoke(facesContext, new Object[]
                      {
                          value
                      });
  
                  SelectItem si = new SelectItem(value, label);
                  selectItems[i] = si;
              }
  
              return selectItems;
          }
  
          throw new IllegalArgumentException("don't know how to access " + valueList.getClass().getName());
      }
  
      @Override
      public boolean isReadOnly(FacesContext facesContext) throws EvaluationException, PropertyNotFoundException
      {
          return true;
      }
  
      @Override
     public void setValue(FacesContext facesContext, Object object) throws EvaluationException, PropertyNotFoundException
     {
         throw new UnsupportedOperationException();
     }
 
     public Object saveState(FacesContext facesContext)
     {
         return new Object[]
             {
                 UIComponentBase.saveAttachedState(facesContext, mbValues),
                 UIComponentBase.saveAttachedState(facesContext, mbLabels),
             };
     }
 
     public void restoreState(FacesContext facesContext, Object object)
     {
         Object[] states = (Object[]) object;
         mbValues = (MethodBinding) UIComponentBase.restoreAttachedState(facesContext, states[0]);
         mbLabels = (MethodBinding) UIComponentBase.restoreAttachedState(facesContext, states[1]);
     }
 
     public boolean isTransient()
     {
         return _transient;
     }
 
     public void setTransient(boolean flag)
     {
         _transient = flag;
     }
 }