org.datanucleus.store.rdbms.mapping.java

Class AbstractContainerMapping

java.lang.Object

org.datanucleus.store.rdbms.mapping.java.JavaTypeMapping

org.datanucleus.store.rdbms.mapping.java.SingleFieldMapping

org.datanucleus.store.rdbms.mapping.java.AbstractContainerMapping

Direct Known Subclasses:

ArrayMapping, CollectionMapping, MapMapping

public abstract class AbstractContainerMapping
extends SingleFieldMapping

Mapping for a field that represents a container of objects, such as a List, a Set, a Collection, a Map, or an array. Has an owner table. Can be represented in the following ways :-

• Using a Join-Table, where the linkage between owner and elements/keys/values is stored in this table
• Using a Foreign-Key in the element/key/value
• Serialised into a single column in the owner table.
• Embedded into the Join-Table
• Serialised into a single-column in the Join-Table

The contents of the container are backed by a store, handling interfacing with the datastore.

Field Summary

Fields inherited from class org.datanucleus.store.rdbms.mapping.java.JavaTypeMapping

absFieldNumber, datastoreMappings, mmd, referenceMapping, roleForMember, storeMgr, table, type

Constructor Summary

Constructors

Constructor and Description
AbstractContainerMapping()

Method Summary

Modifier and Type	Method and Description
protected boolean	containerIsStoredInSingleColumn() Convenience method to return if the container (collection or map) is stored in the owning table as a column.
DatastoreMapping	getDatastoreMapping(int index) Accessor for a datastore mapping
DatastoreMapping[]	getDatastoreMappings() Accessor for the datastore mappings for this java type
String	getJavaTypeForDatastoreMapping(int index) Accessor for the name of the java-type actually used when mapping the particular datastore field.
int	getNumberOfDatastoreMappings() Accessor for the number of datastore fields
Object	getObject(org.datanucleus.ExecutionContext ec, ResultSet resultSet, int[] exprIndex) Method to retrieve an object from the passed JDBC ResultSet.
Table	getTable() Accessor for the datastore class.
boolean	hasSimpleDatastoreRepresentation() Whether the mapping has a simple (single column) datastore representation.
boolean	includeInFetchStatement() This mapping is included in the select statement.
boolean	includeInInsertStatement() This mapping is included in the insert statement.
boolean	includeInUpdateStatement() This mapping is included in the update statement.
void	initialize(org.datanucleus.metadata.AbstractMemberMetaData mmd, Table table, org.datanucleus.ClassLoaderResolver clr) Initialize this JavaTypeMapping for the given field/property.
void	postFetch(org.datanucleus.state.ObjectProvider sm) Method to be called after any fetch of the owner class element.
protected void	prepareDatastoreMapping() Method to prepare a field mapping for use in the datastore.
protected org.datanucleus.store.types.SCO	replaceFieldWithWrapper(org.datanucleus.state.ObjectProvider op, Object value) Method to replace the field that this mapping represents with a SCO wrapper.
void	setObject(org.datanucleus.ExecutionContext ec, PreparedStatement ps, int[] exprIndex, Object value) Method to set a field in the passed JDBC PreparedStatement using this mapping.

Methods inherited from class org.datanucleus.store.rdbms.mapping.java.SingleFieldMapping

getBoolean, getByte, getChar, getDefaultLength, getDouble, getFloat, getInt, getLong, getShort, getString, getValidValues, setBoolean, setByte, setChar, setDouble, setFloat, setInt, setLong, setShort, setString

Methods inherited from class org.datanucleus.store.rdbms.mapping.java.JavaTypeMapping

addDatastoreMapping, equals, failureMessage, getAbsoluteFieldNumber, getColumnMetaDataForMember, getJavaType, getMemberMetaData, getObject, getReferenceMapping, getRoleForMember, getStoreManager, getType, getValueForDatastoreMapping, hashCode, initialize, isNullable, isSerialised, representableAsStringLiteralInStatement, setAbsFieldNumber, setMemberMetaData, setObject, setReferenceMapping, setRoleForMember, setTable

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractContainerMapping

public AbstractContainerMapping()

Method Detail

initialize

public void initialize(org.datanucleus.metadata.AbstractMemberMetaData mmd,
                       Table table,
                       org.datanucleus.ClassLoaderResolver clr)

Initialize this JavaTypeMapping for the given field/property.

Overrides:

initialize in class SingleFieldMapping

Parameters:

mmd - MetaData for the field/property to be mapped (if any)

table - The datastore container storing this mapping (if any)

clr - the ClassLoaderResolver

hasSimpleDatastoreRepresentation

public boolean hasSimpleDatastoreRepresentation()

Whether the mapping has a simple (single column) datastore representation.

Overrides:

hasSimpleDatastoreRepresentation in class JavaTypeMapping

Returns:

Whether it has a simple datastore representation (single column)

prepareDatastoreMapping

protected void prepareDatastoreMapping()

Method to prepare a field mapping for use in the datastore. This creates the column in the table.

Overrides:

prepareDatastoreMapping in class SingleFieldMapping

getJavaTypeForDatastoreMapping

public String getJavaTypeForDatastoreMapping(int index)

Accessor for the name of the java-type actually used when mapping the particular datastore field. This java-type must have an entry in the datastore mappings.

Overrides:

getJavaTypeForDatastoreMapping in class SingleFieldMapping

Parameters:

index - requested datastore field index.

Returns:

the name of java-type for the requested datastore field.

setObject

public void setObject(org.datanucleus.ExecutionContext ec,
                      PreparedStatement ps,
                      int[] exprIndex,
                      Object value)

Method to set a field in the passed JDBC PreparedStatement using this mapping. Only valid when the collection is serialised.

Overrides:

setObject in class SingleFieldMapping

Parameters:

ec - ExecutionContext

ps - The JDBC Prepared Statement to be populated

exprIndex - The parameter positions in the JDBC statement to populate.

value - The value to populate into it

getObject

public Object getObject(org.datanucleus.ExecutionContext ec,
                        ResultSet resultSet,
                        int[] exprIndex)

Method to retrieve an object from the passed JDBC ResultSet. Only valid when the collection is serialised.

Overrides:

getObject in class SingleFieldMapping

Parameters:

ec - ExecutionContext

resultSet - The ResultSet

exprIndex - The parameter position(s) to extract the object from

Returns:

The collection object

getTable

public Table getTable()

Accessor for the datastore class.

Overrides:

getTable in class JavaTypeMapping

Returns:

The datastore class

getNumberOfDatastoreMappings

public int getNumberOfDatastoreMappings()

Accessor for the number of datastore fields

Overrides:

getNumberOfDatastoreMappings in class JavaTypeMapping

Returns:

The number of datastore fields

getDatastoreMapping

public DatastoreMapping getDatastoreMapping(int index)

Accessor for a datastore mapping

Overrides:

getDatastoreMapping in class JavaTypeMapping

Parameters:

index - The id of the mapping

Returns:

The datastore mapping

getDatastoreMappings

public DatastoreMapping[] getDatastoreMappings()

Accessor for the datastore mappings for this java type

Overrides:

getDatastoreMappings in class JavaTypeMapping

Returns:

The datastore mapping(s)

containerIsStoredInSingleColumn

protected boolean containerIsStoredInSingleColumn()

Convenience method to return if the container (collection or map) is stored in the owning table as a column. The container is stored in a single column in the following situations :-

• The FieldMetaData has 'serialized="true"'
• The collection has embedded-element="true" but no join table (and so serialised)
• The map has embedded-key/value="true" but no join table (and so serialised)
• The array has embedded-element="true" but no join table (and so serialised)
• The array has no join table and non-PC elements (and so serialised)

Returns:

Whether it is stored in a single column in the main table.

includeInFetchStatement

public boolean includeInFetchStatement()

This mapping is included in the select statement.

Overrides:

includeInFetchStatement in class JavaTypeMapping

Returns:

Whether to include in select statement

includeInUpdateStatement

public boolean includeInUpdateStatement()

This mapping is included in the update statement.

Overrides:

includeInUpdateStatement in class JavaTypeMapping

Returns:

Whether to include in update statement

includeInInsertStatement

public boolean includeInInsertStatement()

This mapping is included in the insert statement.

Overrides:

includeInInsertStatement in class JavaTypeMapping

Returns:

Whether to include in insert statement

replaceFieldWithWrapper

protected org.datanucleus.store.types.SCO replaceFieldWithWrapper(org.datanucleus.state.ObjectProvider op,
                                                                  Object value)

Method to replace the field that this mapping represents with a SCO wrapper. The wrapper will be suitable for the passed instantiated type and if it is null will be for the declared type of the field.

Parameters:

op - ObjectProvider for the owning object

value - The value to create the wrapper with

Returns:

The SCO wrapper object that the field was replaced with

postFetch

public void postFetch(org.datanucleus.state.ObjectProvider sm)

Method to be called after any fetch of the owner class element.

Parameters:

sm - StateManager of the owner