Module org.eclipse.persistence.core

Package org.eclipse.persistence.descriptors

Interface SerializedObjectPolicy

All Superinterfaces:

Cloneable, Serializable

All Known Implementing Classes:

AbstractSerializedObjectPolicy, SerializedObjectPolicyWrapper

public interface SerializedObjectPolicy
extends Cloneable, Serializable

SerializedObjectPolicy (SOP) could be set on a non-aggregate descriptor. If SerializedObjectPolicy is specified Eclipselink writes out the whole entity object with its privately owned (and nested privately owned) entities and element collections into an additional (likely BLOB) field in the database. If SerializedObjectPolicy is set on an entity then SerializedObjectPolicies with the same field are set on all inheriting entities. The goal is to make reads from the database faster. The draw back is slower writes into the database. So SerializedObjectPolicy may make sense for read-only / read-mostly application for Entity, which always loads all its dependent entities and / or ElementCollections. To use SerializedObjectPolicy, ObjectLevelReadQuery should set a boolean flag

Since:

EclipseLink 2.5.1

See Also:

• In case the serialized object column contains null or obsolete version of the object the query using SerializedObjectPolicy would either throw exception or - if all other fields have been read, too - would build the object using these fields (exactly as in case SerializedObjectPolicy is not used). Note that currently no default implementation of SerializedObjectPolicy is available and this class should be provided by the user.
• SerializedObject

Method Summary

Modifier and Type	Method	Description
SerializedObjectPolicy	clone()
List<DatabaseField>	getAllSelectionFields()	Lists the database fields that should be read by the query using the policy, in case all inherited objects are read using outer joining.
ClassDescriptor	getDescriptor()	get owning descriptor
DatabaseField	getField()	get the field that stores sopObject in the database (sopField)
Object	getObjectFromRow(AbstractRecord databaseRow, AbstractSession session, ObjectLevelReadQuery query)	Deserialize the object from the value corresponding to the policy field, nullify that value, set the object into the row using setSopObject, also return it.
List<DatabaseField>	getSelectionFields()	Lists the database fields that should be read by the query using the policy.
void	initialize(AbstractSession session)	initialize the policy
void	initializeField(AbstractSession session)	unless the field is already initialized by parent descriptor, add the field to the owning descriptor and set field's type
SerializedObjectPolicy	instantiateChild()	instantiate policy for child descriptor
void	postInitialize(AbstractSession session)	postinitialize the policy: determine which mappings are included, which fields should be selected
void	putObjectIntoRow(AbstractRecord databaseRow, Object object, AbstractSession session)	Serialize the object and put the result into the row as a value corresponding to the policy field
void	setDescriptor(ClassDescriptor descriptor)	set owning descriptor
void	setField(DatabaseField field)	set the field that stores sopObject in the database (sopField)

Method Details

getDescriptor

ClassDescriptor getDescriptor()

get owning descriptor

setDescriptor

void setDescriptor(ClassDescriptor descriptor)

set owning descriptor

getField

DatabaseField getField()

get the field that stores sopObject in the database (sopField)

setField

void setField(DatabaseField field)

set the field that stores sopObject in the database (sopField)

clone

SerializedObjectPolicy clone()

instantiateChild

SerializedObjectPolicy instantiateChild()

instantiate policy for child descriptor

initializeField

void initializeField(AbstractSession session)

unless the field is already initialized by parent descriptor, add the field to the owning descriptor and set field's type

initialize

void initialize(AbstractSession session)

initialize the policy

postInitialize

void postInitialize(AbstractSession session)

postinitialize the policy: determine which mappings are included, which fields should be selected

getSelectionFields

List<DatabaseField> getSelectionFields()

Lists the database fields that should be read by the query using the policy. To allow recovery in case of null or invalid sopObject, then this method should return all the fields define by descriptor (descriptor.getFields()).

getAllSelectionFields

List<DatabaseField> getAllSelectionFields()

Lists the database fields that should be read by the query using the policy, in case all inherited objects are read using outer joining. To allow recovery in case of null or invalid sopObject, then this method should return all the fields define by descriptor (descriptor.getAllFields()).

putObjectIntoRow

void putObjectIntoRow(AbstractRecord databaseRow,
 Object object,
 AbstractSession session)

Serialize the object and put the result into the row as a value corresponding to the policy field

getObjectFromRow

Object getObjectFromRow(AbstractRecord databaseRow,
 AbstractSession session,
 ObjectLevelReadQuery query)

Deserialize the object from the value corresponding to the policy field, nullify that value, set the object into the row using setSopObject, also return it. If the object is null or invalid, behaviour depend on whether the policy allows the query to recover or not (see comments to getFieldsToSelect and getAllFieldsToSelect methods): if recovery is possible then the method should return null, otherwise throw QueryException (query is a parameter of this method only because it's required by QueryException).