org.jpox.store.mapped.scostore
Interface CollectionStoreQueryable

public interface CollectionStoreQueryable

Interface representation of the querying capabilities of a backing store for a collection. This is part of the JDOQL "expression" design that will be refactored out when the new query engine replaces it.

Method Summary

QueryExpression	getExistsSubquery(QueryExpression parentStmt, JavaTypeMapping ownerMapping, LogicSetExpression ownerTableExpr, DatastoreIdentifier existsTableAlias) Create a subquery for the given query that selects elements, joining to the owner table.
QueryExpression	getSizeSubquery(QueryExpression parentStmt, JavaTypeMapping ownerMapping, LogicSetExpression ownerTableExpr, DatastoreIdentifier sizeTableAlias) Create a subquery for the size of the collection.
ScalarExpression	joinElementsTo(QueryExpression stmt, QueryExpression parentStmt, JavaTypeMapping ownerMapping, LogicSetExpression ownerTableExpr, DatastoreIdentifier collectionTableAlias, java.lang.Class filteredElementType, ScalarExpression elementExpr, DatastoreIdentifier elementTableAlias, boolean existsQuery) Method used in queries when contains() has been invoked.
QueryExpression	newQueryStatement(StateManager sm, java.lang.String candidateClass, DatastoreIdentifier candidateAlias) Method to return a new Query Statement containing the candidate class.
ResultObjectFactory	newResultObjectFactory(StateManager sm, QueryExpression stmt, boolean ignoreCache, boolean useFetchPlan) Method to return an object factory for processing query statements.

Method Detail

newQueryStatement

QueryExpression newQueryStatement(StateManager sm,
                                  java.lang.String candidateClass,
                                  DatastoreIdentifier candidateAlias)

Method to return a new Query Statement containing the candidate class.

Parameters:

sm - State Manager for the collection.

candidateClass - Class of the elements.

candidateAlias - Alias for the candidate

Returns:

The Query Statement.

newResultObjectFactory

ResultObjectFactory newResultObjectFactory(StateManager sm,
                                           QueryExpression stmt,
                                           boolean ignoreCache,
                                           boolean useFetchPlan)

Method to return an object factory for processing query statements.

Parameters:

sm - State Manager for the collection.

stmt - The Query Statement.

ignoreCache - Whether to ignore the cache.

useFetchPlan - whether to use the fetch plan to retrieve fields in the same query

Returns:

The Persistent object factory.

getExistsSubquery

QueryExpression getExistsSubquery(QueryExpression parentStmt,
                                  JavaTypeMapping ownerMapping,
                                  LogicSetExpression ownerTableExpr,
                                  DatastoreIdentifier existsTableAlias)

Create a subquery for the given query that selects elements, joining to the owner table. This subquery can subsequently be used in an EXISTS expression to determine whether a Collection is empty.

Parameters:

parentStmt - Parent query statement for this subquery

ownerMapping - Id mapping for the owner

ownerTableExpr - Table Expression for the owner that the subquery joins to

existsTableAlias - Alias for this subquery main table

Returns:

Subquery returning the existence of elements

getSizeSubquery

QueryExpression getSizeSubquery(QueryExpression parentStmt,
                                JavaTypeMapping ownerMapping,
                                LogicSetExpression ownerTableExpr,
                                DatastoreIdentifier sizeTableAlias)

Create a subquery for the size of the collection.

Parameters:

parentStmt - Parent query statement for this subquery

ownerMapping - Id mapping for the owner

ownerTableExpr - Table Expression for the owner in the parent statement that the subquery joins to

sizeTableAlias - Alias for this subquery main table

Returns:

Subquery returning the size

joinElementsTo

ScalarExpression joinElementsTo(QueryExpression stmt,
                                QueryExpression parentStmt,
                                JavaTypeMapping ownerMapping,
                                LogicSetExpression ownerTableExpr,
                                DatastoreIdentifier collectionTableAlias,
                                java.lang.Class filteredElementType,
                                ScalarExpression elementExpr,
                                DatastoreIdentifier elementTableAlias,
                                boolean existsQuery)

Method used in queries when contains() has been invoked.

Parameters:

stmt - The Query Statement

parentStmt - the parent Query Statement. If there is no parent, "parentStmt" must be equals to "stmt".

ownerMapping - the mapping for the owner

ownerTableExpr - Table Expression for the owner

collectionTableAlias - Alias for the "Collection" table.

filteredElementType - The Class Type for the filtered element

elementExpr - The Expression for the element

elementTableAlias - The SQL alias to assign to the element table expression

existsQuery - Whether this is joining for an EXISTS query

Returns:

expression to the join