ResultSetDataModel (Java EE 5 SDK)

javax.faces.model Class ResultSetDataModel

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

public class ResultSetDataModel

extends DataModel

ResultSetDataModel is a convenience implementation of DataModel that wraps a ResultSet of Java objects. Note that the specified ResultSet MUST be scrollable. In addition, if input components (that will be updating model values) reference this object in value binding expressions, the specified ResultSet MUST be updatable.

ResultSetDataModel

public ResultSetDataModel()

Construct a new ResultSetDataModel with no specified wrapped data.

ResultSetDataModel

public ResultSetDataModel(ResultSet resultSet)

Construct a new ResultSetDataModel wrapping the specified ResultSet.

参数:

resultSet - ResultSet to be wrapped (if any)

isRowAvailable

public boolean isRowAvailable()

Return true if there is wrappedData available, and the result of calling absolute() on the underlying ResultSet, passing the current value of rowIndex plus one (to account for the fact that ResultSet uses one-relative indexing), returns true. Otherwise, return false.

规范说明:

isRowAvailable in class DataModel

抛出异常:

FacesException - if an error occurs getting the row availability

getRowCount

public int getRowCount()

Return -1, since ResultSet does not provide a standard way to determine the number of available rows without scrolling through the entire ResultSet, and this can be very expensive if the number of rows is large.

规范说明:

getRowCount in class DataModel

抛出异常:

FacesException - if an error occurs getting the row count

getRowData

public Object getRowData()

If row data is available, return a Map representing the values of the columns for the row specified by rowIndex, keyed by the corresponding column names. If no wrapped data is available, return null.

If a non-null Map is returned, its behavior must correspond to the contract for a mutable Map as described in the JavaDocs for AbstractMap, with the following exceptions and specialized behavior:

• The Map, and any supporting objects it returns, must perform all column name comparisons in a case-insensitive manner. This case-insensitivity must be implemented using a case-insensitive Comparator, such as String.CASE_INSENSITIVE_ORDER.
• The following methods must throw UnsupportedOperationException: clear(), remove().
• The entrySet() method must return a Set that has the following behavior:
  • Throw UnsupportedOperationException for any attempt to add or remove entries from the Set, either directly or indirectly through an Iterator returned by the Set.
  • Updates to the value of an entry in this set must write through to the corresponding column value in the underlying ResultSet.
• The keySet() method must return a Set that throws UnsupportedOperationException on any attempt to add or remove keys, either directly or through an Iterator returned by the Set.
• The put() method must throw IllegalArgumentException if a key value for which containsKey() returns false is specified. However, if a key already present in the Map is specified, the specified value must write through to the corresponding column value in the underlying ResultSet.
• The values() method must return a Collection that throws UnsupportedOperationException on any attempt to add or remove values, either directly or through an Iterator returned by the Collection.

规范说明:

getRowData in class DataModel

抛出异常:

FacesException - if an error occurs getting the row data

IllegalArgumentException - if now row data is available at the currently specified row index

getRowIndex

public int getRowIndex()

Description copied from class: DataModel

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.

规范说明:

getRowIndex in class DataModel

抛出异常:

FacesException - if an error occurs getting the row index

setRowIndex

public void setRowIndex(int rowIndex)

Description copied from class: DataModel

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 DataModelListeners.

规范说明:

setRowIndex in class DataModel

参数:

rowIndex - The new zero-relative index (must be non-negative)

抛出异常:

FacesException - if an error occurs setting the row index

IllegalArgumentException - if rowIndex is less than -1

getWrappedData

public Object getWrappedData()

Description copied from class: DataModel

Return the object representing the data wrapped by this DataModel, if any.

规范说明:

getWrappedData in class DataModel

setWrappedData

public void setWrappedData(Object data)

Description copied from class: DataModel

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 DataModelListeners indicating that this row is now selected.

规范说明:

setWrappedData in class DataModel

参数:

data - Data collection to be wrapped, or null to detach from any previous data collection

抛出异常:

ClassCastException - if data is not of the appropriate type for this DataModel implementation

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