org.datanucleus.store.mapped.scostore
Class FKListStore

java.lang.Object
  org.datanucleus.store.mapped.scostore.BaseContainerStore
      org.datanucleus.store.mapped.scostore.ElementContainerStore
          org.datanucleus.store.mapped.scostore.AbstractCollectionStore
              org.datanucleus.store.mapped.scostore.AbstractListStore
                  org.datanucleus.store.mapped.scostore.FKListStore

All Implemented Interfaces:

CollectionStoreQueryable, CollectionStore, ListStore, Store

public abstract class FKListStore
extends AbstractListStore

Representation of a List using a ForeignKey to form a relationship. This class is used where you have a 1-N and the tables are not joined via a join table. There is an owner table and an element table, and the element table has a column being the id of the owner table. This is in contrast to NormalListStore which represents 1-N relationships using a join table. There are 2 possible uses here

• bidirectional - where the owner has a List of elements, and the element has an owner. In this case the element class will have an owner field and index which can be updated directly
• unidirectional - where the owner has a List of elements, but the element knows nothing about the owner. In this case the element class has no owner field. In this case the owner/index columns in the element table have to be updated directly.

Nested Class Summary

Nested classes/interfaces inherited from class org.datanucleus.store.mapped.scostore.ElementContainerStore

ElementContainerStore.ElementInfo

Field Summary

Fields inherited from class org.datanucleus.store.mapped.scostore.AbstractListStore

indexedList

Fields inherited from class org.datanucleus.store.mapped.scostore.ElementContainerStore

clr, containerTable, elementInfo, elementIsPersistentInterface, elementMapping, elementsAreEmbedded, elementsAreSerialised, elementType, emd, iterateUsingDiscriminator, orderMapping, relationDiscriminatorMapping, relationDiscriminatorValue, specialization

Fields inherited from class org.datanucleus.store.mapped.scostore.BaseContainerStore

allowsNull, dba, LOCALISER, ownerMapping, ownerMemberMetaData, relationType, storeMgr

Constructor Summary

FKListStore(AbstractMemberMetaData fmd, MappedStoreManager storeMgr, ClassLoaderResolver clr, FKListStoreSpecialization specialization)
Constructor.

Method Summary

void	clear(StateManager ownerSM) Method to clear the List.
protected boolean	internalAdd(StateManager sm, int startAt, boolean atEnd, java.util.Collection c, int size) Internal method for adding an item to the List.
protected boolean	internalRemove(StateManager sm, java.lang.Object element, int size) Convenience method to remove the specified element from the List.
ScalarExpression	joinElementsTo(QueryExpression stmt, QueryExpression parentStmt, JavaTypeMapping ownerMapping, LogicSetExpression ownerTe, DatastoreIdentifier listTableAlias, java.lang.Class filteredElementType, ScalarExpression elementExpr, DatastoreIdentifier elementTableAlias, boolean existsQuery) Method used in queries when contains() has been invoked.
protected void	manageRemovalOfElement(StateManager ownerSM, java.lang.Object element) Convenience method to manage the removal of an element from the collection, performing any necessary "managed relationship" updates when the field is bidirectional.
protected void	removeAt(StateManager sm, int index, int size) Internal method to remove an object at a location in the List.
java.lang.Object	set(StateManager sm, int index, java.lang.Object element, boolean allowDependentField) Method to set an object in the List at a position.
void	update(StateManager sm, java.util.Collection coll) Method to update the collection to be the supplied collection of elements.
protected boolean	validateElementForWriting(StateManager sm, java.lang.Object element, int index) Method to validate that an element is valid for writing to the datastore.

Methods inherited from class org.datanucleus.store.mapped.scostore.AbstractListStore

add, add, addAll, addAll, get, getIndicesOf, indexOf, iterator, lastIndexOf, listIterator, listIterator, remove, remove, removeAll, subList

Methods inherited from class org.datanucleus.store.mapped.scostore.AbstractCollectionStore

contains, getExistsSubquery, getSizeSubquery, updateEmbeddedElement

Methods inherited from class org.datanucleus.store.mapped.scostore.ElementContainerStore

getContainerTable, getElementInfo, getElementInformationForClass, getElementMapping, getElementType, getEmd, getOrderMapping, getRelationDiscriminatorMapping, getRelationDiscriminatorValue, hasOrderMapping, isElementsAreEmbedded, isElementsAreSerialised, size, validateElementForReading, validateElementForWriting, validateElementType

Methods inherited from class org.datanucleus.store.mapped.scostore.BaseContainerStore

allowsBatching, getDatastoreAdapter, getOwnerMapping, getOwnerMemberMetaData, getRelationType, getStateManagerForEmbeddedPCObject, getStoreManager, isEmbeddedMapping, setOwner

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.datanucleus.store.scostore.CollectionStore

contains, getElementType, hasOrderMapping, size, updateEmbeddedElement

Methods inherited from interface org.datanucleus.store.scostore.Store

getStoreManager

Constructor Detail

FKListStore

public FKListStore(AbstractMemberMetaData fmd,
                   MappedStoreManager storeMgr,
                   ClassLoaderResolver clr,
                   FKListStoreSpecialization specialization)

Constructor.

Parameters:

fmd - Field MetaData for the field that this represents

storeMgr - The Store Manager in use

clr - The ClassLoaderResolver

specialization - The datastore-specific specialization

Method Detail

set

public java.lang.Object set(StateManager sm,
                            int index,
                            java.lang.Object element,
                            boolean allowDependentField)

Method to set an object in the List at a position.

Parameters:

sm - The state manager

index - The item index

element - What to set it to.

allowDependentField - Whether to enable dependent-field deletes during the set

Returns:

The value before setting.

update

public void update(StateManager sm,
                   java.util.Collection coll)

Method to update the collection to be the supplied collection of elements.

Specified by:

update in interface CollectionStore

Overrides:

update in class AbstractCollectionStore

Parameters:

sm - StateManager of the object

coll - The collection to use

internalAdd

protected boolean internalAdd(StateManager sm,
                              int startAt,
                              boolean atEnd,
                              java.util.Collection c,
                              int size)

Internal method for adding an item to the List.

Specified by:

internalAdd in class AbstractListStore

Parameters:

sm - The state manager

startAt - The start position

atEnd - Whether to add at the end

c - The Collection of elements to add.

size - Current size of list (if known). -1 if not known

Returns:

Whether it was successful

internalRemove

protected boolean internalRemove(StateManager sm,
                                 java.lang.Object element,
                                 int size)

Convenience method to remove the specified element from the List.

Specified by:

internalRemove in class AbstractListStore

Parameters:

sm - StateManager of the owner

element - The element

size - Current size of list if known. -1 if not known

Returns:

Whether the List was modified

manageRemovalOfElement

protected void manageRemovalOfElement(StateManager ownerSM,
                                      java.lang.Object element)

Convenience method to manage the removal of an element from the collection, performing any necessary "managed relationship" updates when the field is bidirectional.

Parameters:

ownerSM - StateManager for the collection owner

element - The element

removeAt

protected void removeAt(StateManager sm,
                        int index,
                        int size)

Internal method to remove an object at a location in the List. Differs from the JoinTable List in that it nulls out the owner FK.

Specified by:

removeAt in class AbstractListStore

Parameters:

sm - The state manager.

index - The location

size - Current size of list (if known). -1 if not known

clear

public void clear(StateManager ownerSM)

Method to clear the List. This is called by the List.clear() method, or when the container object is being deleted and the elements are to be removed (maybe for dependent field), or also when updating a Collection and removing all existing prior to adding all new.

Specified by:

clear in interface CollectionStore

Overrides:

clear in class ElementContainerStore

Parameters:

ownerSM - The state manager

validateElementForWriting

protected boolean validateElementForWriting(StateManager sm,
                                            java.lang.Object element,
                                            int index)

Method to validate that an element is valid for writing to the datastore. TODO Minimise differences to super.validateElementForWriting()

Parameters:

sm - StateManager for the List

element - The element to validate

index - The position that the element is being stored at in the list

Returns:

Whether the element was inserted

joinElementsTo

public ScalarExpression joinElementsTo(QueryExpression stmt,
                                       QueryExpression parentStmt,
                                       JavaTypeMapping ownerMapping,
                                       LogicSetExpression ownerTe,
                                       DatastoreIdentifier listTableAlias,
                                       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 equal to "stmt"

ownerMapping - the mapping for the owner.

ownerTe - Table Expression for the owner

filteredElementType - The Class Type for the filtered element

elementExpr - The Expression for the element

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

listTableAlias - The alias for the "List" table

existsQuery - Whether this is joining for an EXISTS query

Returns:

expression to the join