package org.andromda.cartridges.jsf.component.html;
   
   import java.util.ArrayList;
   import java.util.Collection;
   import java.util.Iterator;
   import java.util.List;
   import java.util.ListIterator;
   import javax.faces.context.FacesContext;
   import javax.faces.el.ValueBinding;
  import org.apache.commons.beanutils.PropertyUtils;
  import org.apache.commons.lang.ObjectUtils;
  import org.apache.commons.lang.StringUtils;
  import org.apache.myfaces.component.html.ext.HtmlDataTable;
  
  /**
   * Extends the datatable and provides the ability to have a backing value: this is
   * useful when submitting tables of information.
   *
   * @author Chad Brandon
   */
  public class HtmlExtendedDataTable
      extends HtmlDataTable
  {
      /**
       * Overridden to provide population of the backingValue's items with the value's items (and
       * updating the model afterwards).
       *
       * @see javax.faces.component.UIData#getValue()
       */
      public Object getValue()
      {
          Object value = super.getValue();
          Object backingValue = this.getBackingValue();
          if (backingValue != null)
          {
              final Class valueType = this.getValueType();
              final Class backingValueType = this.getBackingValueType();
              if (valueType != backingValueType)
              {
                  throw new IllegalArgumentException("The 'value' and 'backingValue' must be of the same type");
              }
              final String identifierColumnsString = this.getIdentifierColumns();
              final String[] identifierColumns =
                  StringUtils.isBlank(identifierColumnsString) ? new String[0]
                                                               : StringUtils.trimToEmpty(identifierColumnsString).split(
                      "\\s*,\\s*");
  
              // - handle collections
              if (backingValue instanceof Collection)
              {
                  if (!(backingValue instanceof List))
                  {
                      backingValue = new ArrayList((Collection)backingValue);
                  }
                  if (!(value instanceof List))
                  {
                      value = new ArrayList((Collection)value);
                  }
                  final List backingValues = (List)backingValue;
                  final List values = (List)value;
                  for (final ListIterator iterator = backingValues.listIterator(); iterator.hasNext();)
                  {
                      final Object backingValueItem = iterator.next();
                      for (final Iterator valueIterator = values.iterator(); valueIterator.hasNext();)
                      {
                          final Object valueItem = valueIterator.next();
                          if (this.equal(
                                  backingValueItem,
                                  valueItem,
                                  identifierColumns))
                          {
                              iterator.set(valueItem);
                              break;
                          }
                      }
                  }
                  value = backingValues;
              }
  
              // - handle arrays
              else if (backingValue.getClass().isArray())
              {
                  final Object[] backingValues = (Object[])backingValue;
                  final Object[] values = value != null ? (Object[])value : new Object[0];
                  for (int backingValueCtr = 0; backingValueCtr < backingValues.length; backingValueCtr++)
                  {
                      final Object backingValueItem = backingValues[backingValueCtr];
                      for (int valueCtr = 0; valueCtr < values.length; valueCtr++)
                      {
                          final Object valueItem = values[valueCtr];
                          if (this.equal(
                                  backingValueItem,
                                  valueItem,
                                  identifierColumns))
                          {
                              backingValues[backingValueCtr] = valueItem;
                              break;
                          }
                      }
                 }
                 value = backingValues;
             }
             else
             {
                 throw new IllegalArgumentException("The backing value must be a collection or array");
             }
         }
         this.updateModelValue(value);
         return value;
     }
 
     /**
      * Indicates whether or not this objects are equal, first by comparing them directly for
      * equality and if not equal in that sense compares the columns returned by {@link #getIdentifierColumns()}.
      * @param object1 the first object.
      * @param object2 the second object.
      * @param properties if equality fails, then these properties are compared for equality (all of them must
      *        be equal or else this operation will return false).
      * @return equal true/false
      */
     private boolean equal(
         final Object object1,
         final Object object2,
         final String[] properties)
     {
         boolean equal = object1 == object2;
         if (!equal && object1 != null && object2 != null)
         {
             for (int ctr = 0; ctr < properties.length; ctr++)
             {
                 final String property = properties[ctr];
                 if (StringUtils.isNotBlank(property))
                 {
                     final Object value1 = this.getProperty(
                             object1,
                             property);
                     final Object value2 = this.getProperty(
                             object2,
                             property);
                     if (value1 != null && value2 != null)
                     {
                         equal = value1.equals(value2);
                         if (!equal)
                         {
                             break;
                         }
                     }
                 }
             }
         }
         return equal;
     }
 
     /**
      * Updates the model (i.e. underlying managed bean's value).
      *
      * @param value the value from which to update the model.
      */
     public void updateModelValue(final Object value)
     {
         final ValueBinding binding = getValueBinding(VALUE);
         if (binding != null)
         {
             binding.setValue(
                 this.getFacesContext(),
                 value);
         }
     }
 
     /**
      * The value attribute.
      */
     private static final String VALUE = "value";
 
     /**
      * Gets the type of the backing value attribute.
      * @return Class The backing value's type or null if the backing value
      *         isn't defined.
      */
     private Class getBackingValueType()
     {
         return this.getBindingType(BACKING_VALUE);
     }
 
     /**
      * Gets the value's type attribute or null if value was not defined.
      * Tomahawk 1.1.10 or later: org.apache.myfaces.component.html.ext.HtmlDataTable.getValueType returns String, not Class
      *
      * @return Class the value's type or null if undefined.
      */
     public Class getValueType()
     {
         return this.getBindingType(VALUE);
     }
 
     /**
      * Gets the binding type given the attribute name.
      *
      * @param name the name of the component's attribute.
      * @return type Class the binding type or null if the binding wasn't found.
      */
     private Class getBindingType(final String name)
     {
         Class type = null;
         ValueBinding binding = getValueBinding(name);
         if (binding != null)
         {
             final FacesContext context = this.getFacesContext();
             type = binding.getType(context);
         }
         return type;
     }
 
     private Object getProperty(
         final Object bean,
         final String property)
     {
         try
         {
             return PropertyUtils.getProperty(
                 bean,
                 property);
         }
         catch (final Throwable throwable)
         {
             throw new RuntimeException(throwable);
         }
     }
 
     private Object backingValue = null;
 
     /**
      * The attribute that stores the backing value.
      */
     public static final String BACKING_VALUE = "backingValue";
 
     /**
      * Retrieves the backing value of this extended data table (the backing value contains
      * the values which the result of the value attribute are compared against).
      * @return this.backingValue
      */
     protected Object getBackingValue()
     {
         if (this.backingValue == null)
         {
             final ValueBinding binding = this.getValueBinding(BACKING_VALUE);
             this.backingValue = binding == null ? null : binding.getValue(getFacesContext());
         }
         return this.backingValue;
     }
 
     /**
      * Stores the identifier columns attribute.
      */
     private String identifierColumns;
 
     /**
      * The attribute that stores the identifier columns.
      */
     public static final String IDENTIFIER_COLUMNS = "identifierColumns";
 
     /**
      * Retrieves the identifier columns component attribute.
      *
      * @return this.identifierColumns the identifier columns component attribute.
      */
     protected String getIdentifierColumns()
     {
         if (this.identifierColumns == null)
         {
             this.identifierColumns = (String)this.getAttributes().get(IDENTIFIER_COLUMNS);
             if (this.identifierColumns == null)
             {
                 final ValueBinding binding = this.getValueBinding(IDENTIFIER_COLUMNS);
                 this.identifierColumns =
                     binding == null ? null : ObjectUtils.toString(binding.getValue(getFacesContext()));
             }
         }
         return this.identifierColumns;
     }
 }