javax.faces.model: abstract public class: DataModel

javax.faces.model
abstract public class: DataModel [javadoc | source]

java.lang.Object
   javax.faces.model.DataModel

All Implemented Interfaces:
Iterable

Direct Known Subclasses:
ResultDataModel, ArrayDataModel, ScalarDataModel, ListDataModel, ResultSetDataModel

DataModel is an abstraction around arbitrary data binding technologies that can be used to adapt a variety of data sources for use by JavaServer Faces components that support per-row processing for their child components (such as UIData .

The data collection underlying a DataModel instance is modeled as a collection of row objects that can be accessed by a zero-relative cursor (row index). The APIs provide mechanisms to position to a specified zero-relative row index, and to retrieve an object that represents the data that corresponds to the current row index.

A concrete DataModel instance is attached to a particular collection of underlying data by calling the setWrappedData() method. It can be detached from that underlying data collection by passing a null parameter to this method.

Concrete DataModel implementations must provide a public zero-arguments constructor that calls setWrappedData(null). A convenience constructor that takes a wrapped object of the appropriate type (and passes it on via a call to setWrappedData(), should also be provided.

Event listeners may be registered to receive notifications of when a new row index is selected.

Method from javax.faces.model.DataModel Summary:
addDataModelListener, getDataModelListeners, getRowCount, getRowData, getRowIndex, getWrappedData, isRowAvailable, iterator, removeDataModelListener, setRowIndex, setWrappedData

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from javax.faces.model.DataModel Detail:
public void addDataModelListener(DataModelListener listener) { if (listener == null) { throw new NullPointerException(); } if (listeners == null) { //noinspection CollectionWithoutInitialCapacity listeners = new ArrayList< DataModelListener >(); } listeners.add(listener); } Add a new DataModelListener to the set interested in notifications from this DataModel .
public DataModelListener[] getDataModelListeners() { if (listeners == null) { return EMPTY_DATA_MODEL_LISTENER; } else { return listeners.toArray (new DataModelListener[listeners.size()]); } } Return the set of DataModelListener s interested in notifications from this DataModel . If there are no such listeners, an empty array is returned.
abstract public int getRowCount() Return the number of rows of data objects represented by this DataModel . If the number of rows is unknown, or no `wrappedData` is available, return -1.
abstract public E getRowData() Return an object representing the data for the currenty selected row index. If no `wrappedData` is available, return `null`.
abstract public int getRowIndex() Return the zero-relative index of the currently selected row. If we are not currently positioned on a row, or no `wrappedData` is available, return -1.
abstract public Object getWrappedData() Return the object representing the data wrapped by this DataModel , if any.
abstract public boolean isRowAvailable() Return a flag indicating whether there is `rowData` available at the current `rowIndex`. If no `wrappedData` is available, return `false`.
public Iterator<E> iterator() { return new DataModelIterator< E >(this); } Return a read-only `Iterator` over the row data for this model.
public void removeDataModelListener(DataModelListener listener) { if (listener == null) { throw new NullPointerException(); } if (listeners != null) { listeners.remove(listener); if (listeners.isEmpty()) { listeners = null; } } } Remove an existing DataModelListener from the set interested in notifications from this DataModel .
abstract public void setRowIndex(int rowIndex) Set the zero-relative index of the currently selected row, or -1 to indicate that we are not positioned on a row. It is possible to set the row index at a value for which the underlying data collection does not contain any row data. Therefore, callers may use the `isRowAvailable()` method to detect whether row data will be available for use by the `getRowData()` method. If there is no `wrappedData` available when this method is called, the specified `rowIndex` is stored (and may be retrieved by a subsequent call to `getRowData()`), but no event is sent. Otherwise, if the currently selected row index is changed by this call, a DataModelEvent will be sent to the `rowSelected()` method of all registered DataModelListener s.
abstract public void setWrappedData(Object data) Set the object representing the data collection wrapped by this DataModel . If the specified `data` is `null`, detach this DataModel from any previously wrapped data collection instead. If `data` is non-`null`, the currently selected row index must be set to zero, and a DataModelEvent must be sent to the `rowSelected()` method of all registered DataModelListener s indicating that this row is now selected.