api/src/main/java/javax/faces/component/UIData.java

/*
 * 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 $Author$)
 * @version $Revision$ $Date$
 */
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;
    }
}