/*
    * 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.component;
  
  import java.io.IOException;
  import java.sql.ResultSet;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  import javax.faces.application.FacesMessage;
  import javax.faces.context.FacesContext;
  import javax.faces.el.ValueBinding;
  import javax.faces.event.AbortProcessingException;
  import javax.faces.event.FacesEvent;
  import javax.faces.event.FacesListener;
  import javax.faces.event.PhaseId;
  import javax.faces.model.ArrayDataModel;
  import javax.faces.model.DataModel;
  import javax.faces.model.ListDataModel;
  import javax.faces.model.ResultDataModel;
  import javax.faces.model.ResultSetDataModel;
  import javax.faces.model.ScalarDataModel;
  import javax.servlet.jsp.jstl.sql.Result;
  
  /**
   * Represents a component which has multiple "rows" of data.
   * <p>
   * The children of this component are expected to be UIColumn components.
   * <p>
   * Note that the same set of child components are reused to implement each
   * row of the table in turn during such phases as apply-request-values and
   * render-response. Altering any of the members of these components therefore
   * affects the attribute for every row, except for the following members:
   * <ul>
   * <li>submittedValue
   * <li>value (where no EL binding is used)
   * <li>valid
   * </ul>
   * <p>
   * This reuse of the child components also means that it is not possible
   * to save a reference to a component during table processing, then access
   * it later and expect it to still represent the same row of the table.
   * <h1>
   * Implementation Notes
   * </h1>
   * <p>
   * Each of the UIColumn children of this component has a few component
   * children of its own to render the contents of the table cell. However
   * there can be a very large number of rows in a table, so it isn't
   * efficient for the UIColumn and all its child objects to be duplicated
   * for each row in the table. Instead the "flyweight" pattern is used
   * where a serialized state is held for each row. When setRowIndex is
   * invoked, the UIColumn objects and their children serialize their
   * current state then reinitialise themselves from the appropriate saved
   * state. This allows a single set of real objects to represent multiple
   * objects which have the same types but potentially different internal
   * state. When a row is selected for the first time, its state is set to
   * a clean "initial" state. Transient components (including any read-only
   * component) do not save their state; they are just reinitialised as required.
   * The state saved/restored when changing rows is not the complete
   * component state, just the fields that are expected to vary between
   * rows: "submittedValue", "value", "isValid".
   * </p>
   * <p>
   * Note that a table is a "naming container", so that components
   * within the table have their ids prefixed with the id of the
   * table. Actually, when setRowIndex has been called on a table with
   * id of "zzz" the table pretends to its children that its ID is
   * "zzz_n" where n is the row index. This means that renderers for
   * child components which call component.getClientId automatically
   * get ids of form "zzz_n:childId" thus ensuring that components in
   * different rows of the table get different ids.
   * </p>
   * <p>
   * When decoding a submitted page, this class iterates over all
   * its possible rowIndex values, restoring the appropriate serialized
   * row state then calling processDecodes on the child components. Because
   * the child components (or their renderers) use getClientId to get the
   * request key to look for parameter data, and because this object pretends
  * to have a different id per row ("zzz_n") a single child component can
  * decode data from each table row in turn without being aware that it is
  * within a table. The table's data model is updated before each call to
  * child.processDecodes, so the child decode method can assume that the
  * data model's rowData points to the model object associated with the
  * row currently being decoded. Exactly the same process applies for
  * the later validation and updateModel phases.
  * </p>
  * <p>
  * When the data model for the table is bound to a backing bean property,
  * and no validation errors have occured during processing of a postback,
  * the data model is refetched at the start of the rendering phase
  * (ie after the update model phase) so that the contents of the data model
  * can be changed as a result of the latest form submission. Because the
  * saved row state must correspond to the elements within the data model,
  * the row state must be discarded whenever a new data model is fetched;
  * not doing this would cause all sorts of inconsistency issues. This does
  * imply that changing the state of any of the members "submittedValue", 
  * "value" or "valid" of a component within the table during the
  * invokeApplication phase has no effect on the rendering of the table.
  * When a validation error has occurred, a new DataModel is <i>not</i>
  * fetched, and the saved state of the child components is <i>not</i>
  * discarded.
  * </p>
  * see Javadoc of <a href="http://java.sun.com/j2ee/javaserverfaces/1.1_01/docs/api/index.html">JSF Specification</a> for more.
  * 
  * @JSFComponent
  *   type = "javax.faces.Data"
  *   family = "javax.faces.Data"
  *   desc = "UIData"
  * 
  * @author Manfred Geiler (latest modification by $Author: lu4242 $)
  * @version $Revision: 949325 $ $Date: 2010-05-28 19:38:36 -0500 (Fri, 28 May 2010) $
  */
 public class UIData extends UIComponentBase implements NamingContainer
 {
     public static final String COMPONENT_TYPE = "javax.faces.Data";
     public static final String COMPONENT_FAMILY = "javax.faces.Data";
     private static final String DEFAULT_RENDERER_TYPE = "javax.faces.Table";
     private static final int DEFAULT_FIRST = 0;
     private static final int DEFAULT_ROWS = 0;
 
     private static final int STATE_SIZE = 5;
     private static final int SUPER_STATE_INDEX = 0;
     private static final int FIRST_STATE_INDEX = 1;
     private static final int ROWS_STATE_INDEX = 2;
     private static final int VALUE_STATE_INDEX = 3;
     private static final int VAR_STATE_INDEX = 4;
 
     private static final String FOOTER_FACET_NAME = "footer";
     private static final String HEADER_FACET_NAME = "header";
     private static final Class OBJECT_ARRAY_CLASS = (new Object[0]).getClass();
     private static final int PROCESS_DECODES = 1;
     private static final int PROCESS_VALIDATORS = 2;
     private static final int PROCESS_UPDATES = 3;
 
     private Integer _first = null;
     private Integer _rows = null;
     private Object _value = null;
 
     private int _rowIndex = -1;
     private String _var = null;
 
     // Holds for each row the states of the child components of this UIData.
     // Note that only "partial" component state is saved: the component fields
     // that are expected to vary between rows.
     private Map _rowStates = new HashMap();
 
     /**
      * Handle case where this table is nested inside another table.
      * See method getDataModel for more details.
      * <p>
      * Key: parentClientId (aka rowId when nested within a parent table)
      * Value: DataModel
      */
     private Map _dataModelMap = new HashMap();
 
     // will be set to false if the data should not be refreshed at the beginning of the encode phase
     private boolean _isValidChilds = true;
 
     private Object _initialDescendantComponentState = null;
 
     public void setFooter(UIComponent footer)
     {
         getFacets().put(FOOTER_FACET_NAME, footer);
     }
 
     /**
      * @JSFFacet
      */
     public UIComponent getFooter()
     {
         return (UIComponent) getFacets().get(FOOTER_FACET_NAME);
     }
 
     public void setHeader(UIComponent header)
     {
         getFacets().put(HEADER_FACET_NAME, header);
     }
 
     /**
      * @JSFFacet
      */
     public UIComponent getHeader()
     {
         return (UIComponent) getFacets().get(HEADER_FACET_NAME);
     }
 
     public boolean isRowAvailable()
     {
         return getDataModel().isRowAvailable();
     }
 
     public int getRowCount()
     {
         return getDataModel().getRowCount();
     }
 
     public Object getRowData()
     {
         return getDataModel().getRowData();
     }
 
     public int getRowIndex()
     {
         return _rowIndex;
     }
 
     /**
      * Set the current row index that methods like getRowData use.
      * <p>
      * Param rowIndex can be -1, meaning "no row".
      * <p>
      * @param rowIndex
      */
     public void setRowIndex(int rowIndex)
     {
         if (rowIndex < -1)
         {
             throw new IllegalArgumentException("rowIndex is less than -1");
         }
 
         if (_rowIndex == rowIndex)
         {
             return;
         }
 
         FacesContext facesContext = getFacesContext();
 
         if (_rowIndex == -1)
         {
             if (_initialDescendantComponentState == null)
             {
                 // Create a template that can be used to initialise any row
                 // that we haven't visited before, ie a "saved state" that can
                 // be pushed to the "restoreState" method of all the child
                 // components to set them up to represent a clean row.
                 _initialDescendantComponentState = saveDescendantComponentStates(
                         getChildren().iterator(), false);
             }
         }
         else
         {
             // We are currently positioned on some row, and are about to
             // move off it, so save the (partial) state of the components
             // representing the current row. Later if this row is revisited
             // then we can restore this state.
             _rowStates.put(getClientId(facesContext),
                     saveDescendantComponentStates(getChildren().iterator(),
                             false));
         }
 
         _rowIndex = rowIndex;
 
         DataModel dataModel = getDataModel();
         dataModel.setRowIndex(rowIndex);
 
         String var = getVar();
         if (rowIndex == -1)
         {
             if (var != null)
             {
                 facesContext.getExternalContext().getRequestMap().remove(var);
             }
         }
         else
         {
             if (var != null)
             {
                 if (isRowAvailable())
                 {
                     Object rowData = dataModel.getRowData();
                     facesContext.getExternalContext().getRequestMap().put(var,
                             rowData);
                 }
                 else
                 {
                     facesContext.getExternalContext().getRequestMap().remove(
                             var);
                 }
             }
         }
 
         if (_rowIndex == -1)
         {
             // reset components to initial state
             restoreDescendantComponentStates(getChildren().iterator(),
                     _initialDescendantComponentState, false);
         }
         else
         {
             Object rowState = _rowStates.get(getClientId(facesContext));
             if (rowState == null)
             {
                 // We haven't been positioned on this row before, so just
                 // configure the child components of this component with
                 // the standard "initial" state
                 restoreDescendantComponentStates(getChildren().iterator(),
                         _initialDescendantComponentState, false);
             }
             else
             {
                 // We have been positioned on this row before, so configure
                 // the child components of this component with the (partial)
                 // state that was previously saved. Fields not in the
                 // partial saved state are left with their original values.
                 restoreDescendantComponentStates(getChildren().iterator(),
                         rowState, false);
             }
         }
     }
 
     /**
      * Overwrite the state of the child components of this component
      * with data previously saved by method saveDescendantComponentStates.
      * <p>
      * The saved state info only covers those fields that are expected to
      * vary between rows of a table. Other fields are not modified.
      */
     private void restoreDescendantComponentStates(Iterator childIterator,
             Object state, boolean restoreChildFacets)
     {
         Iterator descendantStateIterator = null;
         while (childIterator.hasNext())
         {
             if (descendantStateIterator == null && state != null)
             {
                 descendantStateIterator = ((Collection) state).iterator();
             }
             UIComponent component = (UIComponent) childIterator.next();
 
             // reset the client id (see spec 3.1.6)
             component.setId(component.getId());
             if(!component.isTransient())
             {
                 Object childState = null;
                 Object descendantState = null;
                 if (descendantStateIterator != null
                         && descendantStateIterator.hasNext())
                 {
                     Object[] object = (Object[]) descendantStateIterator.next();
                     childState = object[0];
                     descendantState = object[1];
                 }
                 if (component instanceof EditableValueHolder)
                 {
                     ((EditableValueHolderState) childState)
                             .restoreState((EditableValueHolder) component);
                 }
                 Iterator childsIterator;
                 if (restoreChildFacets)
                 {
                     childsIterator = component.getFacetsAndChildren();
                 }
                 else
                 {
                     childsIterator = component.getChildren().iterator();
                 }
                 restoreDescendantComponentStates(childsIterator, descendantState,
                         true);
             }
         }
     }
 
     /**
      * Walk the tree of child components of this UIData, saving the parts of
      * their state that can vary between rows.
      * <p>
      * This is very similar to the process that occurs for normal components
      * when the view is serialized. Transient components are skipped (no
      * state is saved for them).
      * <p>
      * If there are no children then null is returned. If there are one or
      * more children, and all children are transient then an empty collection
      * is returned; this will happen whenever a table contains only read-only
      * components.
      * <p>
      * Otherwise a collection is returned which contains an object for every
      * non-transient child component; that object may itself contain a collection
      * of the state of that child's child components.
      */
     private Object saveDescendantComponentStates(Iterator childIterator,
             boolean saveChildFacets)
     {
         Collection childStates = null;
         while (childIterator.hasNext())
         {
             if (childStates == null)
             {
                 childStates = new ArrayList();
             }
             UIComponent child = (UIComponent) childIterator.next();
             if(!child.isTransient())
             {
                 // Add an entry to the collection, being an array of two
                 // elements. The first element is the state of the children
                 // of this component; the second is the state of the current
                 // child itself.
 
                 Iterator childsIterator;
                 if (saveChildFacets)
                 {
                     childsIterator = child.getFacetsAndChildren();
                 }
                 else
                 {
                     childsIterator = child.getChildren().iterator();
                 }
                 Object descendantState = saveDescendantComponentStates(
                         childsIterator, true);
                 Object state = null;
                 if (child instanceof EditableValueHolder)
                 {
                     state = new EditableValueHolderState(
                             (EditableValueHolder) child);
                 }
                 childStates.add(new Object[] { state, descendantState });
             }
         }
         return childStates;
     }
 
     /**
      * Set the maximum number of rows displayed in the table.
      */
     public void setRows(int rows)
     {
         _rows = new Integer(rows);
         if (rows < 0)
             throw new IllegalArgumentException("rows: " + rows);
     }
 
     /**
      * Set the name of the temporary variable that will be exposed to
      * child components of the table to tell them what the "rowData"
      * object for the current row is. This value must be a literal
      * string (EL expression not permitted).
      */
     public void setVar(String var)
     {
         _var = var;
     }
 
     /**
      * Defines the name of the request-scope variable that will hold the current row during iteration.  This value must be a static value.
      * 
      * @JSFProperty
      *   literalOnly = "true"
      *   required = "true"
      */
     public String getVar()
     {
         return _var;
     }
 
     public void setValueBinding(String name, ValueBinding binding)
     {
         if (name == null)
         {
             throw new NullPointerException("name");
         }
         else if (name.equals("value"))
         {
             _dataModelMap.clear();
         }
         else if (name.equals("var") || name.equals("rowIndex"))
         {
             throw new IllegalArgumentException(
                     "You can never set the 'rowIndex' or the 'var' attribute as a value-binding. Set the property directly instead. Name " + name);
         }
         super.setValueBinding(name, binding);
     }
 
     public String getClientId(FacesContext context)
     {
         String clientId = super.getClientId(context);
         int rowIndex = getRowIndex();
         if (rowIndex == -1)
         {
             return clientId;
         }
         return clientId + NamingContainer.SEPARATOR_CHAR + rowIndex;
     }
 
     /**
      * Modify events queued for any child components so that the
      * UIData state will be correctly configured before the event's
      * listeners are executed.
      * <p>
      * Child components or their renderers may register events against
      * those child components. When the listener for that event is
      * eventually invoked, it may expect the uidata's rowData and
      * rowIndex to be referring to the same object that caused the
      * event to fire.
      * <p>
      * The original queueEvent call against the child component has been
      * forwarded up the chain of ancestors in the standard way, making
      * it possible here to wrap the event in a new event whose source
      * is <i>this</i> component, not the original one. When the event
      * finally is executed, this component's broadcast method is invoked,
      * which ensures that the UIData is set to be at the correct row
      * before executing the original event.
      */
     public void queueEvent(FacesEvent event)
     {
         super.queueEvent(new FacesEventWrapper(event, getRowIndex(), this));
     }
 
     /**
      * Ensure that before the event's listeners are invoked this UIData
      * component's "current row" is set to the row associated with the event.
      * <p>
      * See queueEvent for more details. 
      */
     public void broadcast(FacesEvent event) throws AbortProcessingException
     {
         if (event instanceof FacesEventWrapper)
         {
             FacesEvent originalEvent = ((FacesEventWrapper) event)
                     .getWrappedFacesEvent();
             int eventRowIndex = ((FacesEventWrapper) event).getRowIndex();
             int currentRowIndex = getRowIndex();
             setRowIndex(eventRowIndex);
             try
             {
               originalEvent.getComponent().broadcast(originalEvent);
             }
             finally
             {
               setRowIndex(currentRowIndex);
             }
         }
         else
         {
             super.broadcast(event);
         }
     }
 
     /**
      * Perform necessary actions when rendering of this component starts,
      * before delegating to the inherited implementation which calls the
      * associated renderer's encodeBegin method.
      */
     public void encodeBegin(FacesContext context) throws IOException
     {
         _initialDescendantComponentState = null;
         if (_isValidChilds && !hasErrorMessages(context))
         {
             // Clear the data model so that when rendering code calls
             // getDataModel a fresh model is fetched from the backing
             // bean via the value-binding.
             _dataModelMap.clear();
             
             // When the data model is cleared it is also necessary to
             // clear the saved row state, as there is an implicit 1:1
             // relation between objects in the _rowStates and the
             // corresponding DataModel element.
             _rowStates.clear();
         }
         super.encodeBegin(context);
     }
 
     private boolean hasErrorMessages(FacesContext context)
     {
         for(Iterator iter = context.getMessages(); iter.hasNext();)
         {
             FacesMessage message = (FacesMessage) iter.next();
             if(FacesMessage.SEVERITY_ERROR.compareTo(message.getSeverity()) <= 0)
             {
                 return true;
             }
         }
         return false;
     }
 
     /**
      * @see javax.faces.component.UIComponentBase#encodeEnd(javax.faces.context.FacesContext)
      */
     public void encodeEnd(FacesContext context) throws IOException
     {
         try
         {
             setCachedFacesContext(context);
             setRowIndex(-1);
         }
         finally
         {
             setCachedFacesContext(null);
         }
         super.encodeEnd(context);
     }
 
     public void processDecodes(FacesContext context)
     {
         if (context == null)
             throw new NullPointerException("context");
         try
         {
             setCachedFacesContext(context);
             if (!isRendered())
                 return;
             setRowIndex(-1);
             processFacets(context, PROCESS_DECODES);
             processColumnFacets(context, PROCESS_DECODES);
             processColumnChildren(context, PROCESS_DECODES);
             setRowIndex(-1);
             try
             {
                 decode(context);
             }
             catch (RuntimeException e)
             {
                 context.renderResponse();
                 throw e;
             }
         }
         finally
         {
             setCachedFacesContext(null);
         }
     }
 
     public void processValidators(FacesContext context)
     {
         if (context == null)
             throw new NullPointerException("context");
         try
         {
             setCachedFacesContext(context);
             if (!isRendered())
                 return;
             setRowIndex(-1);
             processFacets(context, PROCESS_VALIDATORS);
             processColumnFacets(context, PROCESS_VALIDATORS);
             processColumnChildren(context, PROCESS_VALIDATORS);
             setRowIndex(-1);
     
             // check if an validation error forces the render response for our data
             if (context.getRenderResponse())
             {
                 _isValidChilds = false;
             }
         }
         finally
         {
             setCachedFacesContext(null);
         }
     }
 
     public void processUpdates(FacesContext context)
     {
         if (context == null)
             throw new NullPointerException("context");
         try
         {
             setCachedFacesContext(context);
             if (!isRendered())
                 return;
             setRowIndex(-1);
             processFacets(context, PROCESS_UPDATES);
             processColumnFacets(context, PROCESS_UPDATES);
             processColumnChildren(context, PROCESS_UPDATES);
             setRowIndex(-1);
         
             if (context.getRenderResponse())
             {
                 _isValidChilds = false;
             }
         }
         finally
         {
             setCachedFacesContext(null);
         }
     }
 
     private void processFacets(FacesContext context, int processAction)
     {
         for (Iterator it = getFacets().values().iterator(); it.hasNext();)
         {
             UIComponent facet = (UIComponent) it.next();
             process(context, facet, processAction);
         }
     }
 
     /**
      * Invoke the specified phase on all facets of all UIColumn children
      * of this component. Note that no methods are called on the UIColumn
      * child objects themselves.
      * 
      * @param context is the current faces context.
      * @param processAction specifies a JSF phase: decode, validate or update.
      */
     private void processColumnFacets(FacesContext context, int processAction)
     {
         for (Iterator childIter = getChildren().iterator(); childIter.hasNext();)
         {
             UIComponent child = (UIComponent) childIter.next();
             if (child instanceof UIColumn)
             {
                 if (!child.isRendered())
                 {
                     //Column is not visible
                     continue;
                 }
                 for (Iterator facetsIter = child.getFacets().values()
                         .iterator(); facetsIter.hasNext();)
                 {
                     UIComponent facet = (UIComponent) facetsIter.next();
                     process(context, facet, processAction);
                 }
             }
         }
     }
 
     /**
      * Invoke the specified phase on all non-facet children of all UIColumn
      * children of this component. Note that no methods are called on the
      * UIColumn child objects themselves.
      * 
      * @param context is the current faces context.
      * @param processAction specifies a JSF phase: decode, validate or update.
      */
     private void processColumnChildren(FacesContext context, int processAction)
     {
         int first = getFirst();
         int rows = getRows();
         int last;
         if (rows == 0)
         {
             last = getRowCount();
         }
         else
         {
             last = first + rows;
         }
         for (int rowIndex = first; last==-1 || rowIndex < last; rowIndex++)
         {
             setRowIndex(rowIndex);
 
             //scrolled past the last row
             if (!isRowAvailable())
                 break;
 
             for (Iterator it = getChildren().iterator(); it.hasNext();)
             {
                 UIComponent child = (UIComponent) it.next();
                 if (child instanceof UIColumn)
                 {
                     if (!child.isRendered())
                     {
                         //Column is not visible
                         continue;
                     }
                     for (Iterator columnChildIter = child.getChildren()
                             .iterator(); columnChildIter.hasNext();)
                     {
                         UIComponent columnChild = (UIComponent) columnChildIter
                                 .next();
                         process(context, columnChild, processAction);
                     }
                 }
             }
         }
     }
 
     private void process(FacesContext context, UIComponent component,
             int processAction)
     {
         switch (processAction)
         {
         case PROCESS_DECODES:
             component.processDecodes(context);
             break;
         case PROCESS_VALIDATORS:
             component.processValidators(context);
             break;
         case PROCESS_UPDATES:
             component.processUpdates(context);
             break;
         }
     }
 
     /**
      * Return the datamodel for this table, potentially fetching the data from
      * a backing bean via a value-binding if this is the first time this method
      * has been called.
      * <p>
      * This is complicated by the fact that this table may be nested within
      * another table. In this case a different datamodel should be fetched
      * for each row. When nested within a parent table, the parent reference
      * won't change but parent.getClientId() will, as the suffix changes
      * depending upon the current row index. A map object on this component
      * is therefore used to cache the datamodel for each row of the table.
      * In the normal case where this table is not nested inside a component
      * that changes its id (like a table does) then this map only ever has
      * one entry.
      */
     private DataModel getDataModel()
     {
         DataModel dataModel = null;
         String clientID = "";
         
         UIComponent parent = getParent();
         if (parent != null) {
             clientID = parent.getClientId(getFacesContext());
         }
         dataModel = (DataModel) _dataModelMap.get(clientID);
         if (dataModel == null)
         {
             dataModel = createDataModel();
             _dataModelMap.put(clientID, dataModel);
         }
         return dataModel;
     }
 
     /**
      * Evaluate this object's value property and convert the result into a 
      * DataModel. Normally this object's value property will be a value-binding
      * which will cause the value to be fetched from some backing bean.
      * <p>
      * The result of fetching the value may be a DataModel object, in which
      * case that object is returned directly. If the value is of type
      * List, Array, ResultSet, Result, other object or null then an appropriate
      * wrapper is created and returned.
      * <p>
      * Null is never returned by this method.
      */
     private DataModel createDataModel()
     {
         Object value = getValue();
         if (value == null)
         {
             return EMPTY_DATA_MODEL;
         }
         else if (value instanceof DataModel)
         {
             return (DataModel) value;
         }
         else if (value instanceof List)
         {
             return new ListDataModel((List) value);
         }
         else if (OBJECT_ARRAY_CLASS.isAssignableFrom(value.getClass()))
         {
             return new ArrayDataModel((Object[]) value);
         }
         else if (value instanceof ResultSet)
         {
             return new ResultSetDataModel((ResultSet) value);
         }
         else if (value instanceof Result)
         {
             return new ResultDataModel((Result) value);
         }
         else
         {
             return new ScalarDataModel(value);
         }
     }
 
     private static class FacesEventWrapper extends FacesEvent
     {
         private static final long serialVersionUID = 6648047974065628773L;
         private FacesEvent _wrappedFacesEvent;
         private int _rowIndex;
 
         public FacesEventWrapper(FacesEvent facesEvent, int rowIndex,
                 UIData redirectComponent)
         {
             super(redirectComponent);
             _wrappedFacesEvent = facesEvent;
             _rowIndex = rowIndex;
         }
 
         public PhaseId getPhaseId()
         {
             return _wrappedFacesEvent.getPhaseId();
         }
 
         public void setPhaseId(PhaseId phaseId)
         {
             _wrappedFacesEvent.setPhaseId(phaseId);
         }
 
         public void queue()
         {
             _wrappedFacesEvent.queue();
         }
 
         public String toString()
         {
             return _wrappedFacesEvent.toString();
         }
 
         public boolean isAppropriateListener(FacesListener faceslistener)
         {
             return _wrappedFacesEvent.isAppropriateListener(faceslistener);
         }
 
         public void processListener(FacesListener faceslistener)
         {
             _wrappedFacesEvent.processListener(faceslistener);
         }
 
         public FacesEvent getWrappedFacesEvent()
         {
             return _wrappedFacesEvent;
         }
 
         public int getRowIndex()
         {
             return _rowIndex;
         }
     }
 
     private static final DataModel EMPTY_DATA_MODEL = new DataModel()
     {
         public boolean isRowAvailable()
         {
             return false;
         }
 
         public int getRowCount()
         {
             return 0;
         }
 
         public Object getRowData()
         {
             throw new IllegalArgumentException();
         }
 
         public int getRowIndex()
         {
             return -1;
         }
 
         public void setRowIndex(int i)
         {
             if (i < -1)
                 throw new IllegalArgumentException();
         }
 
         public Object getWrappedData()
         {
             return null;
         }
 
         public void setWrappedData(Object obj)
         {
             if (obj == null)
                 return; //Clearing is allowed
             throw new UnsupportedOperationException(this.getClass().getName()
                     + " UnsupportedOperationException");
         }
     };
 
     public void setValue(Object value)
     {
         _value = value;
         _dataModelMap.clear();
         _rowStates.clear();
         _isValidChilds = true;
     }
 
     public Object saveState(FacesContext context)
     {
         Object[] values = new Object[STATE_SIZE];
         values[SUPER_STATE_INDEX] = super.saveState(context);
         values[FIRST_STATE_INDEX] = _first;
         values[ROWS_STATE_INDEX] = _rows;
         values[VALUE_STATE_INDEX] = _value;
         values[VAR_STATE_INDEX] = _var;
         return values;
     }
 
     public void restoreState(FacesContext context, Object state)
     {
         Object[] values = (Object[]) state;
         super.restoreState(context, values[0]);
         _first = (Integer) values[FIRST_STATE_INDEX];
         _rows = (Integer) values[ROWS_STATE_INDEX];
         _value = values[VALUE_STATE_INDEX];
         _var = (String) values[VAR_STATE_INDEX];
     }
 
     private class EditableValueHolderState
     {
         private final Object _value;
         private final boolean _localValueSet;
         private final boolean _valid;
         private final Object _submittedValue;
 
         public EditableValueHolderState(EditableValueHolder evh)
         {
             _value = evh.getLocalValue();
             _localValueSet = evh.isLocalValueSet();
             _valid = evh.isValid();
             _submittedValue = evh.getSubmittedValue();
         }
 
         public void restoreState(EditableValueHolder evh)
         {
             evh.setValue(_value);
             evh.setLocalValueSet(_localValueSet);
             evh.setValid(_valid);
             evh.setSubmittedValue(_submittedValue);
         }
     }
 
     public UIData()
     {
         setRendererType(DEFAULT_RENDERER_TYPE);
     }
 
     public String getFamily()
     {
         return COMPONENT_FAMILY;
     }
 
     public void setFirst(int first)
     {
         if (first < 0)
         {
             throw new IllegalArgumentException("Illegal value for first row: " + first);
         }
         _first = new Integer(first);
     }
 
     /**
      * The index of the first row to be displayed, where 0 is the first row.
      * 
      * @JSFProperty
      */
     public int getFirst()
     {
         if (_first != null)
         {
             return _first.intValue();
         }
         ValueBinding vb = getValueBinding("first");
         Number v = vb != null ? (Number) vb.getValue(getFacesContext()) : null;
         return v != null ? v.intValue() : DEFAULT_FIRST;
     }
 
     /**
      * The number of rows to be displayed.  Specify zero for all remaining rows in the table.
      * 
      * @JSFProperty
      */
     public int getRows()
     {
         if (_rows != null)
         {
             return _rows.intValue();
         }
         ValueBinding vb = getValueBinding("rows");
         Number v = vb != null ? (Number) vb.getValue(getFacesContext()) : null;
         return v != null ? v.intValue() : DEFAULT_ROWS;
     }
 
     /**
      * An EL expression that specifies the data model that backs this table.  The value can be of any type.
      * 
      * A value of type DataModel is used directly.  Array-like parameters of type java.util.List, array of Object, 
      * java.sql.ResultSet, or javax.servlet.jsp.jstl.sql.Result are wrapped in a DataModel.
      * 
      * Other values are wrapped in a DataModel as a single row.
      * @JSFProperty
      */
     public Object getValue()
     {
         if (_value != null)
             return _value;
         ValueBinding vb = getValueBinding("value");
         return vb != null ? vb.getValue(getFacesContext()) : null;
     }
 }