Package org.apache.tapestry5.jpa
Class JpaGridDataSource<E>
java.lang.Object
org.apache.tapestry5.jpa.JpaGridDataSource<E>
- All Implemented Interfaces:
GridDataSource
A simple implementation of
GridDataSource
based on a
EntityManager and a known
entity class. This implementation does support multiple
sort
constraints
.
This class is not thread-safe; it maintains internal state.
Typically, an instance of this object is created fresh as needed (that is, it is not stored
between requests).- Since:
- 5.3
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Constructor Summary
ConstructorsConstructorDescriptionJpaGridDataSource
(javax.persistence.EntityManager entityManager, Class<E> entityType) -
Method Summary
Modifier and TypeMethodDescriptionprotected void
applyAdditionalConstraints
(javax.persistence.criteria.CriteriaQuery<?> criteria, javax.persistence.criteria.Root<E> root, javax.persistence.criteria.CriteriaBuilder builder) int
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
-
JpaGridDataSource
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Method Details
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getAvailableRows
Returns the number of rows available in the data source.- Specified by:
getAvailableRows
in interfaceGridDataSource
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prepare
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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applyAdditionalConstraints
protected void applyAdditionalConstraints(javax.persistence.criteria.CriteriaQuery<?> criteria, javax.persistence.criteria.Root<E> root, javax.persistence.criteria.CriteriaBuilder builder) -
getRowValue
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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getRowType
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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