org.datanucleus.store.rdbms.mapping.java

Class SerialisedLocalFileMapping

java.lang.Object

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

org.datanucleus.store.rdbms.mapping.java.SerialisedLocalFileMapping

All Implemented Interfaces:

MappingCallbacks

public class SerialisedLocalFileMapping
extends JavaTypeMapping
implements MappingCallbacks

Mapping where we want to serialise a (Serializable) field to a local file. Since the field will be stored in the local file system then this will have no "datastore mapping" (i.e column) as such. The user defines the folder in which values of this field will be stored in metadata, and the filename in that folder is basically the "id" of the owning object. Assumes that the user is not storing multiple fields in the same folder.

Handling roll back

Whenever an insert/update/delete is performed it registers a listener on any active transaction and allows a hook to attempt to roll back any changes to the value before that operation.

Field Summary

Fields

Modifier and Type	Field and Description
static String	SERIALIZE_TO_FOLDER_EXTENSION

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
SerialisedLocalFileMapping()

Method Summary

Modifier and Type	Method and Description
protected Object	deserialiseFieldValue(org.datanucleus.state.ObjectProvider op) Method to deserialise the value from file and return it.
protected String	getFilenameForObjectProvider(org.datanucleus.state.ObjectProvider op)
Class	getJavaType() Accessor for the java type being mapped.
boolean	includeInFetchStatement() Accessor for whether this mapping is to be included in any fetch statement.
boolean	includeInInsertStatement() Accessor for whether this mapping is to be included in the insert statement.
boolean	includeInUpdateStatement() Accessor for whether this mapping is to be included in the update statement.
void	initialize(org.datanucleus.metadata.AbstractMemberMetaData mmd, Table table, org.datanucleus.ClassLoaderResolver clr) Initialize this JavaTypeMapping for the supplied table and field/property metadata.
void	insertPostProcessing(org.datanucleus.state.ObjectProvider op) Hook so that we can handle any post-processing on the insert of a particular field.
void	postFetch(org.datanucleus.state.ObjectProvider op) Method called after the retrieval of the object, so that additional operations can be performed if necessary.
void	postInsert(org.datanucleus.state.ObjectProvider op) Method called after the insert of the object so that additional operations can be performed if necessary.
void	postUpdate(org.datanucleus.state.ObjectProvider op) Method called after the update of the object, so that additional operations can be performed if necessary.
void	preDelete(org.datanucleus.state.ObjectProvider op) Method called before the delete of objects, so that additional operations can be performed if necessary.
protected void	serialiseFieldValue(org.datanucleus.state.ObjectProvider op, Object value) Method to serialise the value from the ObjectProvider to file.

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

addDatastoreMapping, equals, failureMessage, getAbsoluteFieldNumber, getBoolean, getByte, getChar, getColumnMetaDataForMember, getDatastoreMapping, getDatastoreMappings, getDouble, getFloat, getInt, getJavaTypeForDatastoreMapping, getLong, getMemberMetaData, getNumberOfDatastoreMappings, getObject, getObject, getReferenceMapping, getRoleForMember, getShort, getStoreManager, getString, getTable, getType, getValueForDatastoreMapping, hashCode, hasSimpleDatastoreRepresentation, initialize, isNullable, isSerialised, representableAsStringLiteralInStatement, setAbsFieldNumber, setBoolean, setByte, setChar, setDouble, setFloat, setInt, setLong, setMemberMetaData, setObject, setObject, setReferenceMapping, setRoleForMember, setShort, setString, setTable

Methods inherited from class java.lang.Object

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

Field Detail

SERIALIZE_TO_FOLDER_EXTENSION

public static final String SERIALIZE_TO_FOLDER_EXTENSION

See Also:

Constant Field Values

Constructor Detail

SerialisedLocalFileMapping

public SerialisedLocalFileMapping()

Method Detail

initialize

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

Description copied from class: JavaTypeMapping

Initialize this JavaTypeMapping for the supplied table and field/property metadata. Subclasses should override this method to perform any datastore initialization operations. Assumes the "roleForMember" is already set

Overrides:

initialize in class JavaTypeMapping

Parameters:

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

table - The table storing this mapping (if any)

clr - the ClassLoaderResolver

includeInFetchStatement

public boolean includeInFetchStatement()

Description copied from class: JavaTypeMapping

Accessor for whether this mapping is to be included in any fetch statement.

Overrides:

includeInFetchStatement in class JavaTypeMapping

Returns:

Whether to include this mapping in a fetch statement

includeInUpdateStatement

public boolean includeInUpdateStatement()

Description copied from class: JavaTypeMapping

Accessor for whether this mapping is to be included in the update statement.

Overrides:

includeInUpdateStatement in class JavaTypeMapping

Returns:

Whether to include in update statement

includeInInsertStatement

public boolean includeInInsertStatement()

Description copied from class: JavaTypeMapping

Accessor for whether this mapping is to be included in the insert statement.

Overrides:

includeInInsertStatement in class JavaTypeMapping

Returns:

Whether to include in insert statement

getJavaType

public Class getJavaType()

Description copied from class: JavaTypeMapping

Accessor for the java type being mapped. This is the java type that the mapping represents. Some examples :

• if the field is of type "MyClass" then the mapping will be OIDMapping (or subclass) the javaType will be OID, and the type will be MyClass.
• if the field is of type "int" then the mapping will be IntegerMapping, the javaType will be Integer, and the type will be int.

The "java type" is the java-type name used in the plugin.xml mapping file

Specified by:

getJavaType in class JavaTypeMapping

Returns:

The java type

insertPostProcessing

public void insertPostProcessing(org.datanucleus.state.ObjectProvider op)

Description copied from interface: MappingCallbacks

Hook so that we can handle any post-processing on the insert of a particular field. For example with Oracle we need to insert "EMPTY_CLOB" and then immediately after do a SELECT of it and update the contents of the CLOB/BLOB.

Specified by:

insertPostProcessing in interface MappingCallbacks

Parameters:

op - ObjectProvider

postInsert

public void postInsert(org.datanucleus.state.ObjectProvider op)

Description copied from interface: MappingCallbacks

Method called after the insert of the object so that additional operations can be performed if necessary.

Specified by:

postInsert in interface MappingCallbacks

Parameters:

op - ObjectProvider of the owner

postFetch

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

Description copied from interface: MappingCallbacks

Method called after the retrieval of the object, so that additional operations can be performed if necessary.

Specified by:

postFetch in interface MappingCallbacks

Parameters:

op - ObjectProvider of the owner

postUpdate

public void postUpdate(org.datanucleus.state.ObjectProvider op)

Description copied from interface: MappingCallbacks

Method called after the update of the object, so that additional operations can be performed if necessary.

Specified by:

postUpdate in interface MappingCallbacks

Parameters:

op - ObjectProvider of the owner

preDelete

public void preDelete(org.datanucleus.state.ObjectProvider op)

Description copied from interface: MappingCallbacks

Method called before the delete of objects, so that additional operations can be performed if necessary.

Specified by:

preDelete in interface MappingCallbacks

Parameters:

op - ObjectProvider of the owner

getFilenameForObjectProvider

protected String getFilenameForObjectProvider(org.datanucleus.state.ObjectProvider op)

serialiseFieldValue

protected void serialiseFieldValue(org.datanucleus.state.ObjectProvider op,
                                   Object value)

Method to serialise the value from the ObjectProvider to file.

Parameters:

op - The ObjectProvider

value - The value being serialised

deserialiseFieldValue

protected Object deserialiseFieldValue(org.datanucleus.state.ObjectProvider op)

Method to deserialise the value from file and return it.

Parameters:

op - The ObjectProvider to get the value for

Returns:

The value currently stored