org.datanucleus.store.rdbms.table

Class ElementContainerTable

java.lang.Object

org.datanucleus.store.rdbms.table.AbstractTable

org.datanucleus.store.rdbms.table.TableImpl

org.datanucleus.store.rdbms.table.JoinTable

org.datanucleus.store.rdbms.table.ElementContainerTable

All Implemented Interfaces:

org.datanucleus.store.schema.table.Table

Direct Known Subclasses:

ArrayTable, CollectionTable

public abstract class ElementContainerTable
extends JoinTable

Representation of a join table for a container of elements. Can be used for collections, lists, sets and arrays. There can be multiple JoinTable objects referring to the same underlying datastore object. If the JoinTable is shared by multiple fields for example then there will be one for each relation.

Field Summary

Fields

Modifier and Type	Field and Description
protected JavaTypeMapping	elementMapping Mapping of an element.
protected JavaTypeMapping	orderMapping Order mapping, to provide part of the primary key.
protected JavaTypeMapping	relationDiscriminatorMapping Optional mapping for a column used to discriminate between elements of one collection from another.
protected String	relationDiscriminatorValue Value to use with any relation discriminator column for objects of this field placed in the join table.

Fields inherited from class org.datanucleus.store.rdbms.table.JoinTable

mmd, ownerMapping, ownerTable, ownerType

Fields inherited from class org.datanucleus.store.rdbms.table.AbstractTable

columns, columnsByIdentifier, dba, existsInDatastore, identifier, state, storeMgr, TABLE_STATE_INITIALIZED, TABLE_STATE_INITIALIZED_MODIFIED, TABLE_STATE_NEW, TABLE_STATE_PK_INITIALIZED, TABLE_STATE_VALIDATED

Constructor Summary

Constructors

Constructor and Description
ElementContainerTable(Table ownerTable, DatastoreIdentifier tableName, org.datanucleus.metadata.AbstractMemberMetaData mmd, RDBMSStoreManager storeMgr) Constructor.

Method Summary

Modifier and Type	Method and Description
protected void	applyUserPrimaryKeySpecification(org.datanucleus.metadata.PrimaryKeyMetaData pkmd) Convenience method to apply the user specification of <primary-key> columns
JavaTypeMapping	getElementMapping() Accessor for the "element" mapping end of the relationship.
abstract String	getElementType() Access the element type class name
protected List	getExpectedCandidateKeys() Accessor for the candidate keys for this table.
List	getExpectedForeignKeys(org.datanucleus.ClassLoaderResolver clr) Accessor for the expected foreign keys for this table.
protected Set	getExpectedIndices(org.datanucleus.ClassLoaderResolver clr) Accessor for the indices for this table.
protected ForeignKey	getForeignKeyToElement(DatastoreClass elementTable, boolean autoMode, JavaTypeMapping m) Convenience method to generate a ForeignKey from this join table to an element table using the specified mapping.
protected ForeignKey	getForeignKeyToOwner(DatastoreClass ownerTable, boolean autoMode) Convenience method to generate a ForeignKey from this join table to an owner table.
JavaTypeMapping	getMemberMapping(org.datanucleus.metadata.AbstractMemberMetaData mmd) Accessor not used by this table.
JavaTypeMapping	getOrderMapping() Accessor for the order mapping.
JavaTypeMapping	getRelationDiscriminatorMapping() Accessor for the element discriminator mapping.
String	getRelationDiscriminatorValue() Accessor for the element discriminator value.
void	initialize(org.datanucleus.ClassLoaderResolver clr) Method to initialise the table definition.

Methods inherited from class org.datanucleus.store.rdbms.table.JoinTable

getIdMapping, getOwnerMapping, getOwnerMemberMetaData, getOwnerTable, getPrimaryKey, requiresPrimaryKey

Methods inherited from class org.datanucleus.store.rdbms.table.TableImpl

createConstraints, dropConstraints, getSQLAddCandidateKeyStatements, getSQLAddFKStatements, getSQLCreateIndexStatements, getSQLCreateStatements, getSQLDropStatements, initializeColumnInfoForPrimaryKeyColumns, initializeColumnInfoFromDatastore, logMapping, postInitialize, preInitialize, validate, validateColumns, validateConstraints, validatePrimaryKey

Methods inherited from class org.datanucleus.store.rdbms.table.AbstractTable

addColumn, addColumnInternal, allowDDLOutput, assertIsInitialized, assertIsInitializedModified, assertIsPKInitialized, assertIsPKUninitialized, assertIsUninitialized, assertIsValidated, create, drop, equals, executeDdlStatement, executeDdlStatementList, exists, getCatalogName, getClassMetaData, getColumn, getColumnForName, getColumnForPosition, getColumns, getDatastoreIdentifierFullyQualified, getDiscriminatorMetaData, getIdentifier, getMemberColumnMappingForEmbeddedMember, getMemberColumnMappingForMember, getMemberColumnMappings, getName, getNumberOfColumns, getSchemaName, getStoreManager, getSurrogateColumn, getSurrogateMapping, getVersionMetaData, hasColumn, hasColumnName, hashCode, isInitialized, isInitializedModified, isPKInitialized, isValidated, tableExistsInDatastore, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

elementMapping

protected JavaTypeMapping elementMapping

Mapping of an element. This is either a PersistableMapping to the element table, or an EmbeddedElementPCMapping (when PC elements are embedded), or a simple mapping (when using non-PC elements), or a SerialisedPCMapping, or a SerialisedReferenceMapping. It will be specified in the MetaData using the <element> tag.

orderMapping

protected JavaTypeMapping orderMapping

Order mapping, to provide part of the primary key. In the case of a List this represents the ordering index. In the case of a Set this represents an index for allowing duplicates, or where the element is embedded and is of a type that can't be part of the PK. It will be specified in the MetaData using the <order> tag.

relationDiscriminatorMapping

protected JavaTypeMapping relationDiscriminatorMapping

Optional mapping for a column used to discriminate between elements of one collection from another. Used where the join table is being shared by more than 1 relation. Specified using the metadata extension "relation-discriminator-column" in the "field" element.

relationDiscriminatorValue

protected String relationDiscriminatorValue

Value to use with any relation discriminator column for objects of this field placed in the join table. Specified using the metadata extension "relation-discriminator-value" in the "field" element.

Constructor Detail

ElementContainerTable

public ElementContainerTable(Table ownerTable,
                             DatastoreIdentifier tableName,
                             org.datanucleus.metadata.AbstractMemberMetaData mmd,
                             RDBMSStoreManager storeMgr)

Constructor.

Parameters:

ownerTable - Table of the owner of this member

tableName - Identifier name of this table

mmd - MetaData for the member owning this join table

storeMgr - The Store Manager managing these tables.

Method Detail

initialize

public void initialize(org.datanucleus.ClassLoaderResolver clr)

Method to initialise the table definition. Adds the owner mapping.

Parameters:

clr - The ClassLoaderResolver

getElementType

public abstract String getElementType()

Access the element type class name

Returns:

the element type class name

applyUserPrimaryKeySpecification

protected void applyUserPrimaryKeySpecification(org.datanucleus.metadata.PrimaryKeyMetaData pkmd)

Convenience method to apply the user specification of <primary-key> columns

Parameters:

pkmd - MetaData for the primary key

getMemberMapping

public JavaTypeMapping getMemberMapping(org.datanucleus.metadata.AbstractMemberMetaData mmd)

Accessor not used by this table.

Parameters:

mmd - MetaData for the field whose mapping we want

Returns:

The mapping

getElementMapping

public JavaTypeMapping getElementMapping()

Accessor for the "element" mapping end of the relationship. This is used where the element is persistable and has its own table (not embedded), or where the element is a simple type.

Returns:

The column mapping for the element.

getOrderMapping

public JavaTypeMapping getOrderMapping()

Accessor for the order mapping. The columns in this mapping are part of the primary key.

Returns:

Order mapping (where required)

getRelationDiscriminatorMapping

public JavaTypeMapping getRelationDiscriminatorMapping()

Accessor for the element discriminator mapping.

Returns:

Element discriminator mapping (where required)

getRelationDiscriminatorValue

public String getRelationDiscriminatorValue()

Accessor for the element discriminator value.

Returns:

Element discriminator value (where required)

getForeignKeyToOwner

protected ForeignKey getForeignKeyToOwner(DatastoreClass ownerTable,
                                          boolean autoMode)

Convenience method to generate a ForeignKey from this join table to an owner table.

Parameters:

ownerTable - The owner table

autoMode - Whether we are in auto mode (where we generate the keys regardless of what the metadata says)

Returns:

The ForeignKey

getForeignKeyToElement

protected ForeignKey getForeignKeyToElement(DatastoreClass elementTable,
                                            boolean autoMode,
                                            JavaTypeMapping m)

Convenience method to generate a ForeignKey from this join table to an element table using the specified mapping.

Parameters:

elementTable - The element table

autoMode - Whether we are in auto mode (where we generate the keys regardless of what the metadata says)

m - The mapping to the element table

Returns:

The ForeignKey

getExpectedForeignKeys

public List getExpectedForeignKeys(org.datanucleus.ClassLoaderResolver clr)

Accessor for the expected foreign keys for this table.

Overrides:

getExpectedForeignKeys in class TableImpl

Parameters:

clr - The ClassLoaderResolver

Returns:

The expected foreign keys.

getExpectedIndices

protected Set getExpectedIndices(org.datanucleus.ClassLoaderResolver clr)

Accessor for the indices for this table. This includes both the user-defined indices (via MetaData), and the ones required by foreign keys (required by relationships).

Overrides:

getExpectedIndices in class TableImpl

Parameters:

clr - The ClassLoaderResolver

Returns:

The indices

getExpectedCandidateKeys

protected List getExpectedCandidateKeys()

Accessor for the candidate keys for this table.

Overrides:

getExpectedCandidateKeys in class TableImpl

Returns:

The indices