org.garret.perst
Interface IPersistent

All Superinterfaces:

java.io.Externalizable, java.io.Serializable

All Known Subinterfaces:

BitIndex, Blob, FieldIndex, GenericIndex, Index, IPersistentSet, PatriciaTrie, SortedCollection, SpatialIndex, SpatialIndexR2, TimeSeries

All Known Implementing Classes:

L2List, L2ListElem, Persistent, PersistentCollection, PersistentComparator, PersistentResource, PersistentString, Relation, TimeSeries.Block, Version, VersionHistory

public interface IPersistent

extends java.io.Externalizable

Interface of all persistent capable objects

Method Summary

void	assignOid(Storage storage, int oid, boolean raw) Assign OID to the object.
void	deallocate() Deallocate persistent object from the database
int	getOid() Get object identifier (OID)
Storage	getStorage() Get storage in which this object is stored
void	invalidate() Invalidate object.
boolean	isDeleted() Check if object is deleted by Java GC from process memory
boolean	isModified() Check if object was modified within current transaction
boolean	isPersistent() Check if object is persistent
boolean	isRaw() Check if object is stub and has to be loaded from the database
void	load() Load object from the database (if needed)
void	loadAndModify() Load object from the database (if needed) and mark it as modified
void	makePersistent(Storage storage) Explicitely make object peristent.
void	modify() Mark object as modified.
void	onLoad() Method called by the database after loading of the object.
void	onStore() Method called by the database before storing of the object.
boolean	recursiveLoading() Specified whether object should be automatically loaded when it is referenced by other loaded peristent object.
void	store() Save object in the database

Methods inherited from interface java.io.Externalizable

readExternal, writeExternal

Method Detail

assignOid

void assignOid(Storage storage,
               int oid,
               boolean raw)

Assign OID to the object. This method is used by storage class and you should not invoke it directly

Parameters:

storage - associated storage

oid - object identifier

deallocate

void deallocate()

Deallocate persistent object from the database

getOid

int getOid()

Get object identifier (OID)

Returns:

OID (0 if object is not persistent yet)

getStorage

Storage getStorage()

Get storage in which this object is stored

Returns:

storage containing this object (null if object is not persistent yet)

invalidate

void invalidate()

Invalidate object. Invalidated object has to be explicitly reloaded usin3g load() method. Attempt to store invalidated object will cause StoraegError exception.

isDeleted

boolean isDeleted()

Check if object is deleted by Java GC from process memory

Returns:

true if object is deleted by GC

isModified

boolean isModified()

Check if object was modified within current transaction

Returns:

true if object is persistent and was modified within current transaction

isPersistent

boolean isPersistent()

Check if object is persistent

Returns:

true if object has assigned OID

isRaw

boolean isRaw()

Check if object is stub and has to be loaded from the database

Returns:

true if object has to be loaded from the database

load

void load()

Load object from the database (if needed)

loadAndModify

void loadAndModify()

Load object from the database (if needed) and mark it as modified

makePersistent

void makePersistent(Storage storage)

Explicitely make object peristent. Usually objects are made persistent implicitlely using "persistency on reachability apporach", but this method allows to do it explicitly

Parameters:

storage - storage in which object should be stored

modify

void modify()

Mark object as modified. Object will be saved to the database during transaction commit.

onLoad

void onLoad()

Method called by the database after loading of the object. It can be used to initialize transient fields of the object. Default implementation of this method do nothing

onStore

void onStore()

Method called by the database before storing of the object. It can be used to save or close transient fields of the object. Default implementation of this method do nothing

recursiveLoading

boolean recursiveLoading()

Specified whether object should be automatically loaded when it is referenced by other loaded peristent object. Default implementation of this method returns true making all cluster of referenced objects loaded together. To avoid main memory overflow you should stop recursive loading of all objects from the database to main memory by redefining this method in some classes and returing false in it. In this case object has to be loaded explicitely using Persistent.load method.

Returns:

true if object is automatically loaded

store

void store()

Save object in the database