org.jpox.store.rdbms.scostore
Class ElementContainerStore

java.lang.Object
  org.jpox.store.rdbms.scostore.ElementContainerStore

Direct Known Subclasses:

AbstractArrayStore, AbstractCollectionStore

public abstract class ElementContainerStore
extends java.lang.Object

Representation of the store of an element-based container. This is used to represent either a collection or an array. There are 3 types of situation that we try to cater for with respect to elements.

• element-type is PC with "new-table" or "superclass-table" inheritance. In this case we will have elementInfo with 1 entry.
• element-type is PC with "subclass-table" inheritance. In this case we will have elementInfo with "n" entries (1 for each subclass type with its own table). We also have emd being the MetaData for the element-type.
• element-type is Reference type. In this case we will have elementInfo with "n" entries (1 for each implementation type).
• element-type is non-PC. In this case we have no elementInfo and no emd

Version:

$Revision: 1.79 $

Nested Class Summary

class

ElementContainerStore.ElementInfo Inner class wrapping the information required for a valid element type.

Field Summary

protected java.lang.String	addStmt Statement for adding an element to the container.
protected boolean	allowsNull Whether the container allows null elements/values.
protected java.lang.String	clearStmt Statement for clearing the container.
protected org.jpox.ClassLoaderResolver	clr ClassLoader resolver.
protected org.jpox.store.mapped.DatastoreContainerObject	containerTable Table containing the link between owner and element.
protected org.jpox.store.mapped.DatastoreAdapter	dba Datastore adapter in use by this store.
protected ElementContainerStore.ElementInfo[]	elementInfo Information for the elements of this container.
protected boolean	elementIsPersistentInterface Whether the element is of a persistent-interface (defined using "") type.
protected org.jpox.store.mapped.mapping.JavaTypeMapping	elementMapping Mapping for the element.
protected boolean	elementsAreEmbedded Whether the elements are embedded.
protected boolean	elementsAreSerialised Whether the elements are serialised.
protected java.lang.String	elementType Type of the element.
protected org.jpox.store.mapped.DatastoreIdentifier	elmIdentifier Identifier for elements in JDOQL queries.
protected org.jpox.metadata.AbstractClassMetaData	emd MetaData for the "element-type" class.
protected boolean	iterateUsingDiscriminator Flag to set whether the iterator statement will use a discriminator or not.
protected static org.jpox.util.Localiser	LOCALISER Localiser for messages.
protected org.jpox.store.mapped.mapping.JavaTypeMapping	orderMapping Mapping for an ordering column to allow for duplicates in the container.
protected org.jpox.store.mapped.mapping.JavaTypeMapping	ownerMapping Mapping to the owner of the container.
protected org.jpox.metadata.AbstractMemberMetaData	ownerMemberMetaData MetaData for the field/property in the owner with this container.
protected org.jpox.store.mapped.mapping.JavaTypeMapping	relationDiscriminatorMapping Optional mapping to distinguish elements of one collection from another when sharing the join table.
protected java.lang.String	relationDiscriminatorValue Value to use to discriminate between elements of this collection from others using the same join table.
protected java.lang.String	removeStmt Statement for removing an element from the container.
protected RDBMSManager	storeMgr Manager for the store.
protected boolean	usingDiscriminatorInSizeStmt Whether we are using a discriminator in the "size" statement.

Constructor Summary

protected

ElementContainerStore(org.jpox.store.StoreManager storeMgr, org.jpox.ClassLoaderResolver clr) Constructor.

Method Summary

protected boolean	allowsBatching() Convenience method to return if the RDBMS supports batching and the user wants batching.
void	clear(org.jpox.StateManager ownerSM) Clear the association from owner to all elements.
protected java.lang.String	getAddStmt() Generates the statement for adding items.
protected java.lang.String	getClearStmt() Generate statement for clearing the container.
protected ElementContainerStore.ElementInfo[]	getElementInformationForClass() Convenience method to find the element information relating to the element type.
java.lang.String	getElementType() Accessor for the element type stored in this container.
org.jpox.store.mapped.mapping.JavaTypeMapping	getOwnerMapping() Accessor for the owner mapping.
protected java.lang.String	getSizeStmt() Generate statement for getting the size of the container.
protected org.jpox.StateManager	getStateManagerForEmbeddedPCObject(org.jpox.StateManager sm, java.lang.Object obj, JoinTable table) Method to return the StateManager for an embedded PC object (element, key, value).
org.jpox.store.StoreManager	getStoreManager() Accessor for the RDBMSManager.
boolean	hasOrderMapping() Accessor for whether the store has an order mapping, to allow for duplicates or ordering.
protected boolean	isEmbeddedMapping(org.jpox.store.mapped.mapping.JavaTypeMapping mapping) Check if the mapping correspond to a non pc object or embedded field
abstract java.util.Iterator	iterator(org.jpox.StateManager ownerSM) Accessor for an iterator through the container elements.
org.jpox.store.query.ResultObjectFactory	newResultObjectFactory(org.jpox.StateManager sm, org.jpox.store.mapped.expression.QueryExpression stmt, boolean ignoreCache, boolean useFetchPlan) Method to generate a new result object factory from which to retrieve element objects.
protected int	populateElementDiscriminatorInStatement(org.jpox.ObjectManager om, java.sql.PreparedStatement ps, int jdbcPosition, boolean includeSubclasses, ElementContainerStore.ElementInfo info) Convenience method to populate the passed PreparedStatement with the value from the element discriminator, optionally including all subclasses of the element type.
protected int	populateElementInStatement(org.jpox.ObjectManager om, java.sql.PreparedStatement ps, java.lang.Object element, int jdbcPosition) Convenience method to populate the passed PreparedStatement with the value for the element.
protected int	populateEmbeddedElementFieldsInStatement(org.jpox.StateManager sm, java.lang.Object element, java.sql.PreparedStatement ps, int jdbcPosition, JoinTable joinTable) Convenience method to populate the passed PreparedStatement with the field values from the embedded element starting at the specified jdbc position.
protected int	populateOrderInStatement(org.jpox.ObjectManager om, java.sql.PreparedStatement ps, int idx, int jdbcPosition) Convenience method to populate the passed PreparedStatement with the value for the order index.
protected int	populateOwnerInStatement(org.jpox.StateManager sm, org.jpox.ObjectManager om, java.sql.PreparedStatement ps, int jdbcPosition) Convenience method to populate the passed PreparedStatement with the value from the owner.
protected int	populateRelationDiscriminatorInStatement(org.jpox.ObjectManager om, java.sql.PreparedStatement ps, int jdbcPosition) Convenience method to populate the passed PreparedStatement with the value for the distinguisher value.
protected void	setOwnerMemberMetaData(org.jpox.metadata.AbstractMemberMetaData mmd) Method to set the owner field/property MetaData and sets whether null elements/values are allowed.
int	size(org.jpox.StateManager sm) Method to return the size of the container.
protected boolean	validateElementForReading(org.jpox.StateManager sm, java.lang.Object element) Method to check if an element is already persistent or is persistent but managed by a different persistence manager.
protected boolean	validateElementForWriting(org.jpox.StateManager sm, java.lang.Object element, org.jpox.store.FieldValues fieldValues) Method to check if an element is already persistent, or is managed by a different Persistencemanager.
protected boolean	validateElementType(org.jpox.ClassLoaderResolver clr, java.lang.Object element) Method to validate an element against the accepted type.

Methods inherited from class java.lang.Object

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

Field Detail

iterateUsingDiscriminator

protected boolean iterateUsingDiscriminator

Flag to set whether the iterator statement will use a discriminator or not.

elementInfo

protected ElementContainerStore.ElementInfo[] elementInfo

Information for the elements of this container. When the "element-type" table is new-table, or superclass-table then there is 1 value here. When the "element-type" table uses subclass-table, or when it is a reference type then there can be multiple.

emd

protected org.jpox.metadata.AbstractClassMetaData emd

MetaData for the "element-type" class. Not used for reference types since no metadata is present for the declared type.

containerTable

protected org.jpox.store.mapped.DatastoreContainerObject containerTable

Table containing the link between owner and element. Not set when using FK relations.

elementMapping

protected org.jpox.store.mapped.mapping.JavaTypeMapping elementMapping

Mapping for the element.

elementType

protected java.lang.String elementType

Type of the element.

elementsAreEmbedded

protected boolean elementsAreEmbedded

Whether the elements are embedded.

elementsAreSerialised

protected boolean elementsAreSerialised

Whether the elements are serialised.

elementIsPersistentInterface

protected boolean elementIsPersistentInterface

Whether the element is of a persistent-interface (defined using "") type.

orderMapping

protected org.jpox.store.mapped.mapping.JavaTypeMapping orderMapping

Mapping for an ordering column to allow for duplicates in the container. Can also be used for ordering elements in a List/array. Can also be used where we have an embedded object and so need to form the PK with something.

relationDiscriminatorMapping

protected org.jpox.store.mapped.mapping.JavaTypeMapping relationDiscriminatorMapping

Optional mapping to distinguish elements of one collection from another when sharing the join table.

relationDiscriminatorValue

protected java.lang.String relationDiscriminatorValue

Value to use to discriminate between elements of this collection from others using the same join table.

elmIdentifier

protected final org.jpox.store.mapped.DatastoreIdentifier elmIdentifier

Identifier for elements in JDOQL queries.

clr

protected org.jpox.ClassLoaderResolver clr

ClassLoader resolver.

clearStmt

protected java.lang.String clearStmt

Statement for clearing the container.

addStmt

protected java.lang.String addStmt

Statement for adding an element to the container.

removeStmt

protected java.lang.String removeStmt

Statement for removing an element from the container.

usingDiscriminatorInSizeStmt

protected boolean usingDiscriminatorInSizeStmt

Whether we are using a discriminator in the "size" statement.

LOCALISER

protected static final org.jpox.util.Localiser LOCALISER

Localiser for messages.

storeMgr

protected RDBMSManager storeMgr

Manager for the store.

dba

protected org.jpox.store.mapped.DatastoreAdapter dba

Datastore adapter in use by this store.

ownerMapping

protected org.jpox.store.mapped.mapping.JavaTypeMapping ownerMapping

Mapping to the owner of the container.

ownerMemberMetaData

protected org.jpox.metadata.AbstractMemberMetaData ownerMemberMetaData

MetaData for the field/property in the owner with this container.

allowsNull

protected boolean allowsNull

Whether the container allows null elements/values.

Constructor Detail

ElementContainerStore

protected ElementContainerStore(org.jpox.store.StoreManager storeMgr,
                                org.jpox.ClassLoaderResolver clr)

Constructor.

Parameters:

storeMgr - Manager for the store

clr - ClassLoader resolver

Method Detail

getElementInformationForClass

protected ElementContainerStore.ElementInfo[] getElementInformationForClass()

Convenience method to find the element information relating to the element type. Used specifically for the "element-type" of a collection/array to find the elements which have table information. Not used for reference types.

Returns:

Element information relating to the element type

hasOrderMapping

public boolean hasOrderMapping()

Accessor for whether the store has an order mapping, to allow for duplicates or ordering.

Returns:

Whether an order mapping is present.

getElementType

public java.lang.String getElementType()

Accessor for the element type stored in this container.

Returns:

The element type.

validateElementType

protected boolean validateElementType(org.jpox.ClassLoaderResolver clr,
                                      java.lang.Object element)

Method to validate an element against the accepted type.

Parameters:

clr - The ClassLoaderResolver

element - The element to validate

Returns:

Whether it is valid.

validateElementForReading

protected boolean validateElementForReading(org.jpox.StateManager sm,
                                            java.lang.Object element)

Method to check if an element is already persistent or is persistent but managed by a different persistence manager.

Parameters:

sm - The state manager of this owner

element - The element

Returns:

Whether it is valid for reading.

validateElementForWriting

protected boolean validateElementForWriting(org.jpox.StateManager sm,
                                            java.lang.Object element,
                                            org.jpox.store.FieldValues fieldValues)

Method to check if an element is already persistent, or is managed by a different Persistencemanager. If not persistent, this will persist it.

Parameters:

sm - The state manager of this owner

element - The element

fieldValues - any initial field values to use if persisting the element

Returns:

Whether the element was persisted during this call

populateElementInStatement

protected int populateElementInStatement(org.jpox.ObjectManager om,
                                         java.sql.PreparedStatement ps,
                                         java.lang.Object element,
                                         int jdbcPosition)

Convenience method to populate the passed PreparedStatement with the value for the element. Not used with embedded PC elements.

Parameters:

om - Object Manager

ps - The PreparedStatement

element - The element

jdbcPosition - Position in JDBC statement to populate

Returns:

The next position in the JDBC statement

populateOrderInStatement

protected int populateOrderInStatement(org.jpox.ObjectManager om,
                                       java.sql.PreparedStatement ps,
                                       int idx,
                                       int jdbcPosition)

Convenience method to populate the passed PreparedStatement with the value for the order index.

Parameters:

om - Object Manager

ps - The PreparedStatement

idx - The order value

jdbcPosition - Position in JDBC statement to populate

Returns:

The next position in the JDBC statement

populateRelationDiscriminatorInStatement

protected int populateRelationDiscriminatorInStatement(org.jpox.ObjectManager om,
                                                       java.sql.PreparedStatement ps,
                                                       int jdbcPosition)

Convenience method to populate the passed PreparedStatement with the value for the distinguisher value.

Parameters:

om - Object Manager

ps - The PreparedStatement

jdbcPosition - Position in JDBC statement to populate

Returns:

The next position in the JDBC statement

populateElementDiscriminatorInStatement

protected int populateElementDiscriminatorInStatement(org.jpox.ObjectManager om,
                                                      java.sql.PreparedStatement ps,
                                                      int jdbcPosition,
                                                      boolean includeSubclasses,
                                                      ElementContainerStore.ElementInfo info)

Convenience method to populate the passed PreparedStatement with the value from the element discriminator, optionally including all subclasses of the element type.

Parameters:

om - Persistence Manager

ps - The PreparedStatement

jdbcPosition - Position in JDBC statement to populate

includeSubclasses - Whether to include subclasses

info - The element information

Returns:

The next position in the JDBC statement

populateEmbeddedElementFieldsInStatement

protected int populateEmbeddedElementFieldsInStatement(org.jpox.StateManager sm,
                                                       java.lang.Object element,
                                                       java.sql.PreparedStatement ps,
                                                       int jdbcPosition,
                                                       JoinTable joinTable)

Convenience method to populate the passed PreparedStatement with the field values from the embedded element starting at the specified jdbc position.

Parameters:

sm - State Manager of the owning container

element - The embedded element

ps - The PreparedStatement

jdbcPosition - JDBC position in the statement to start at

joinTable - The Join table where the elements are embedded

Returns:

The next JDBC position

getClearStmt

protected java.lang.String getClearStmt()

Generate statement for clearing the container.

 DELETE FROM CONTAINERTABLE
 WHERE OWNERCOL = ?
 [AND RELATION_DISCRIM=?]
 

TODO Add a discriminator restriction on this statement so we only clear ones with a valid discriminator value

Returns:

Statement for clearing the container.

iterator

public abstract java.util.Iterator iterator(org.jpox.StateManager ownerSM)

Accessor for an iterator through the container elements.

Parameters:

ownerSM - State Manager for the container.

Returns:

The Iterator

clear

public void clear(org.jpox.StateManager ownerSM)

Clear the association from owner to all elements. Provides cascade-delete when the elements being deleted are PC types.

Parameters:

ownerSM - State Manager for the container.

getSizeStmt

protected java.lang.String getSizeStmt()

Generate statement for getting the size of the container. The order part is only present when an order mapping is used. The discriminator part is only present when the element has a discriminator.

 SELECT COUNT(*) FROM TBL THIS
 [INNER JOIN ELEM_TBL ELEM ON TBL.COL = ELEM.ID] - when no null
 [LEFT OUTER JOIN ELEM_TBL ELEM ON TBL.COL = ELEM.ID] - when allows null
 WHERE THIS.OWNERCOL=?
 [AND THIS.ORDERCOL IS NOT NULL]
 [AND (DISCRIMINATOR=? OR DISCRMINATOR=? OR DISCRIMINATOR=? [OR DISCRIMINATOR IS NULL])]
 [AND RELATION_DISCRIM=?]
 

The discriminator part includes all subclasses of the element type. If the element is in a different table to the container then an INNER JOIN will be present to link the two tables, and table aliases will be present also. TODO Update this to allow for getting the size when more than 1 element table.

Returns:

The Statement returning the size of the container.

size

public int size(org.jpox.StateManager sm)

Method to return the size of the container.

Parameters:

sm - The state manager.

Returns:

The size.

getAddStmt

protected java.lang.String getAddStmt()

Generates the statement for adding items. The EMBEDDEDFIELDX columns are only added for embedded PC elements.

 
 INSERT INTO COLLTABLE (OWNERCOL,[ELEMENTCOL],[EMBEDDEDFIELD1, EMBEDDEDFIELD2,...],[ORDERCOL]) 
 VALUES (?,?,?)
 

Returns:

The Statement for adding an item

newResultObjectFactory

public org.jpox.store.query.ResultObjectFactory newResultObjectFactory(org.jpox.StateManager sm,
                                                                       org.jpox.store.mapped.expression.QueryExpression stmt,
                                                                       boolean ignoreCache,
                                                                       boolean useFetchPlan)

Method to generate a new result object factory from which to retrieve element objects.

Parameters:

sm - State Manager for owner

stmt - The query

ignoreCache - Whether to ignore the cache

useFetchPlan - Whether to use the current FetchPlan

Returns:

The Result object factory

setOwnerMemberMetaData

protected void setOwnerMemberMetaData(org.jpox.metadata.AbstractMemberMetaData mmd)

Method to set the owner field/property MetaData and sets whether null elements/values are allowed.

Parameters:

mmd - MetaData for the field/property owning this backing store.

getStoreManager

public org.jpox.store.StoreManager getStoreManager()

Accessor for the RDBMSManager.

Returns:

The RDBMSManager.

getOwnerMapping

public org.jpox.store.mapped.mapping.JavaTypeMapping getOwnerMapping()

Accessor for the owner mapping.

Returns:

Owner mapping.

isEmbeddedMapping

protected boolean isEmbeddedMapping(org.jpox.store.mapped.mapping.JavaTypeMapping mapping)

Check if the mapping correspond to a non pc object or embedded field

Parameters:

mapping - the mapping

Returns:

true if the field is embedded into one column

populateOwnerInStatement

protected int populateOwnerInStatement(org.jpox.StateManager sm,
                                       org.jpox.ObjectManager om,
                                       java.sql.PreparedStatement ps,
                                       int jdbcPosition)

Convenience method to populate the passed PreparedStatement with the value from the owner.

Parameters:

sm - State Manager

om - Object Manager

ps - The PreparedStatement

jdbcPosition - Position in JDBC statement to populate

Returns:

The next position in the JDBC statement

getStateManagerForEmbeddedPCObject

protected org.jpox.StateManager getStateManagerForEmbeddedPCObject(org.jpox.StateManager sm,
                                                                   java.lang.Object obj,
                                                                   JoinTable table)

Method to return the StateManager for an embedded PC object (element, key, value). It creates one if the element is not currently managed.

Parameters:

sm - State Manager of the owner

obj - The embedded PC object

table - Join table where the objects are stored

Returns:

The state manager

allowsBatching

protected boolean allowsBatching()

Convenience method to return if the RDBMS supports batching and the user wants batching.

Returns:

If batching of statements is permissible