Class NullDataSource
java.lang.Object
org.apache.tapestry5.internal.grid.NullDataSource
- All Implemented Interfaces:
GridDataSource
An implementation of
GridDataSource
used when the value null is provided as the
source.-
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionint
Returns the number of rows available in the data source.Returns the type of value in the rows, or null if not known.getRowValue
(int index) Returns the row value at the provided index.void
prepare
(int startIndex, int endIndex, List<SortConstraint> sortConstraints) Invoked to allow the source to prepare to present values.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface org.apache.tapestry5.grid.GridDataSource
getAvailableRows, isEmpty
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Constructor Details
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NullDataSource
public NullDataSource()
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Method Details
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getAvailableRows
Description copied from interface:GridDataSource
Returns the number of rows available in the data source.- Specified by:
getAvailableRows
in interfaceGridDataSource
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getRowType
Description copied from interface:GridDataSource
Returns the type of value in the rows, or null if not known. This value is used to create a defaultBeanModel
when no such model is explicitly provided.- Specified by:
getRowType
in interfaceGridDataSource
- Returns:
- the row type, or null
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prepare
Description copied from interface:GridDataSource
Invoked to allow the source to prepare to present values. This gives the source a chance to pre-fetch data (when appropriate) and informs the source of the desired sort order. Sorting comes first, then extraction by range.- Specified by:
prepare
in interfaceGridDataSource
- Parameters:
startIndex
- the starting index to be retrievedendIndex
- the ending index to be retrievedsortConstraints
- identify how data is to be sorted
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getRowValue
Description copied from interface:GridDataSource
Returns the row value at the provided index. This method will be invoked in sequential order. In rare instances,GridDataSource.getAvailableRows()
may return a different number of rows than are actually available (i.e., the database was changed between calls toGridDataSource.getAvailableRows()
and the call toGridDataSource.prepare(int, int, java.util.List)
). In that case, this method should return null for any out-of-range indexes.- Specified by:
getRowValue
in interfaceGridDataSource
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