net.ontopia.persistence.proxy

Class RDBMSAccess

java.lang.Object

net.ontopia.persistence.proxy.RDBMSAccess

All Implemented Interfaces:

StorageAccessIF

public class RDBMSAccess
extends Object
implements StorageAccessIF

INTERNAL: A storage access implementation accessing relational databases using JDBC.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	batch_updates
protected boolean	closed
protected Connection	connection
protected boolean	debug
protected Collection<FlushableIF>	flushable
protected Map<Class<?>,ClassAccessIF>	handlers
protected String	id
protected RDBMSMapping	mapping
protected boolean	readonly
protected RDBMSStorage	storage

Constructor Summary

Constructors

Constructor and Description
RDBMSAccess(String id, RDBMSStorage storage, boolean readonly)

Method Summary

Modifier and Type	Method and Description
void	abort() INTERNAL: Aborts all changes performed in the transaction.
void	close() INTERNAL: Closes the storage access, which allows it to free its resources.
void	commit() INTERNAL: Commits the changes performed in the transaction.
void	createObject(ObjectAccessIF oaccess, Object object) INTERNAL: Called by the transaction when it requests the new object to be created in the data repository.
QueryIF	createQuery(JDOQuery jdoquery, ObjectAccessIF oaccess, AccessRegistrarIF registrar, boolean lookup_identities) INTERNAL: Build a QueryIF from the specified JDO query instance.
QueryIF	createQuery(String name, ObjectAccessIF oaccess, AccessRegistrarIF registrar) INTERNAL: Creates a query instance for the given transaction.
void	deleteObject(ObjectAccessIF oaccess, Object object) INTERNAL: Called by the transaction when it requests the object to be deleted in the data repository.
void	flush() INTERNAL: Called when the transaction requires the transaction changes to be stored by the storage access (i.e.
IdentityIF	generateIdentity(Class<?> type) INTERNAL: Called by the application when it requests a new object identity for a given object type.
Connection	getConnection() INTERNAL: Returns the JDBC database connection used.
protected ClassAccessIF	getHandler(Class<?> type) INTERNAL: Gets up the handler class that is used to manage objects of the given class.
String	getId() INTERNAL: Gets the storage access id.
String	getProperty(String property) INTERNAL: Gets the value of the specified property.
StorageIF	getStorage() INTERNAL: Returns the storage definition that the access uses.
boolean	isReadOnly() INTERNAL: Returns true if the storage access is read-only.
protected boolean	isSQLException(Throwable e)
Object	loadField(AccessRegistrarIF registrar, IdentityIF identity, int field) INTERNAL: Requests the loading of the specified field for the given object identity.
Object	loadFieldMultiple(AccessRegistrarIF registrar, Collection<IdentityIF> identities, IdentityIF current, Class<?> type, int field) INTERNAL: Requests the loading of the specified field for all the given object identities.
boolean	loadObject(AccessRegistrarIF registrar, IdentityIF identity) INTERNAL: Check for the existence of the object identity in the data repository.
protected void	needsFlushing(FlushableIF handler)
PreparedStatement	prepareStatement(String sql)
void	storeDirty(ObjectAccessIF oaccess, Object object) INTERNAL: Stores object fields that are dirty in the database.
boolean	validate() INTERNAL: Returns true if the storage access is valid.
protected boolean	validateConnection(Connection conn)

Methods inherited from class java.lang.Object

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

Field Detail

debug

protected boolean debug

id

protected String id

readonly

protected boolean readonly

storage

protected RDBMSStorage storage

mapping

protected RDBMSMapping mapping

connection

protected Connection connection

closed

protected boolean closed

handlers

protected Map<Class<?>,ClassAccessIF> handlers

batch_updates

protected boolean batch_updates

flushable

protected Collection<FlushableIF> flushable

Constructor Detail

RDBMSAccess

public RDBMSAccess(String id,
                   RDBMSStorage storage,
                   boolean readonly)

Method Detail

getId

public String getId()

Description copied from interface: StorageAccessIF

INTERNAL: Gets the storage access id. This id is unique for a given StorageIF instance.

Specified by:

getId in interface StorageAccessIF

getStorage

public StorageIF getStorage()

Description copied from interface: StorageAccessIF

INTERNAL: Returns the storage definition that the access uses.

Specified by:

getStorage in interface StorageAccessIF

isReadOnly

public boolean isReadOnly()

Description copied from interface: StorageAccessIF

INTERNAL: Returns true if the storage access is read-only.

Specified by:

isReadOnly in interface StorageAccessIF

getProperty

public String getProperty(String property)

Description copied from interface: StorageAccessIF

INTERNAL: Gets the value of the specified property.

Specified by:

getProperty in interface StorageAccessIF

getConnection

public Connection getConnection()

INTERNAL: Returns the JDBC database connection used. It is important that this connection is neither closed, nor commited or rolled back. If this access has already been closed, a non-transactional read connection is requested from the storage. The connection is validated using validateConnection and renewed if not validated.

prepareStatement

public PreparedStatement prepareStatement(String sql)
                                   throws SQLException

Throws:

SQLException

isSQLException

protected boolean isSQLException(Throwable e)

getHandler

protected ClassAccessIF getHandler(Class<?> type)

INTERNAL: Gets up the handler class that is used to manage objects of the given class.

validate

public boolean validate()

Description copied from interface: StorageAccessIF

INTERNAL: Returns true if the storage access is valid.

Specified by:

validate in interface StorageAccessIF

validateConnection

protected boolean validateConnection(Connection conn)

commit

public void commit()

Description copied from interface: StorageAccessIF

INTERNAL: Commits the changes performed in the transaction.

Specified by:

commit in interface StorageAccessIF

abort

public void abort()

Description copied from interface: StorageAccessIF

INTERNAL: Aborts all changes performed in the transaction.

Specified by:

abort in interface StorageAccessIF

close

public void close()

Description copied from interface: StorageAccessIF

INTERNAL: Closes the storage access, which allows it to free its resources.

Specified by:

close in interface StorageAccessIF

flush

public void flush()

Description copied from interface: StorageAccessIF

INTERNAL: Called when the transaction requires the transaction changes to be stored by the storage access (i.e. written to the database).

This method exists mainly to allow storage access implementations to optimize its communication with data repositories. An example of this is writing transaction changes in batches to improve performance.

Note that the transaction will always call this method at the end of its store method. It will do this so that it is sure that the changes will be visible inside the data repository.

Specified by:

flush in interface StorageAccessIF

loadObject

public boolean loadObject(AccessRegistrarIF registrar,
                          IdentityIF identity)

Description copied from interface: StorageAccessIF

INTERNAL: Check for the existence of the object identity in the data repository. An exception will be thrown if the object does not exist. If it exists the access registrar will be notified.

Specified by:

loadObject in interface StorageAccessIF

Returns:

true if object was found in the data store, false otherwise.

loadField

public Object loadField(AccessRegistrarIF registrar,
                        IdentityIF identity,
                        int field)

Description copied from interface: StorageAccessIF

INTERNAL: Requests the loading of the specified field for the given object identity. An exception will be thrown if the object does not exist. If it exists the access registrar will be notified.

Specified by:

loadField in interface StorageAccessIF

Returns:

The value loaded for the specific field. Note that if the field is a reference field the identity will be returned, not the actual object. This is because the storage system does not deal with persistent object instances directly.

loadFieldMultiple

public Object loadFieldMultiple(AccessRegistrarIF registrar,
                                Collection<IdentityIF> identities,
                                IdentityIF current,
                                Class<?> type,
                                int field)

Description copied from interface: StorageAccessIF

INTERNAL: Requests the loading of the specified field for all the given object identities. An exception will be thrown if the current object does not exist. If it exists the access registrar will be notified.

Specified by:

loadFieldMultiple in interface StorageAccessIF

Returns:

The value loaded for the specific field. Note that if the field is a reference field the identity will be returned, not the actual object. This is because the storage system does not deal with persistent object instances directly.

createObject

public void createObject(ObjectAccessIF oaccess,
                         Object object)

Description copied from interface: StorageAccessIF

INTERNAL: Called by the transaction when it requests the new object to be created in the data repository. The ObjectAccessIF object is used to access information about the object as needed.

Specified by:

createObject in interface StorageAccessIF

deleteObject

public void deleteObject(ObjectAccessIF oaccess,
                         Object object)

Description copied from interface: StorageAccessIF

INTERNAL: Called by the transaction when it requests the object to be deleted in the data repository.

Specified by:

deleteObject in interface StorageAccessIF

storeDirty

public void storeDirty(ObjectAccessIF oaccess,
                       Object object)

Description copied from interface: StorageAccessIF

INTERNAL: Stores object fields that are dirty in the database.

Specified by:

storeDirty in interface StorageAccessIF

needsFlushing

protected void needsFlushing(FlushableIF handler)

createQuery

public QueryIF createQuery(String name,
                           ObjectAccessIF oaccess,
                           AccessRegistrarIF registrar)

Description copied from interface: StorageAccessIF

INTERNAL: Creates a query instance for the given transaction.

Specified by:

createQuery in interface StorageAccessIF

createQuery

public QueryIF createQuery(JDOQuery jdoquery,
                           ObjectAccessIF oaccess,
                           AccessRegistrarIF registrar,
                           boolean lookup_identities)

Description copied from interface: StorageAccessIF

INTERNAL: Build a QueryIF from the specified JDO query instance.

Specified by:

createQuery in interface StorageAccessIF

generateIdentity

public IdentityIF generateIdentity(Class<?> type)

Description copied from interface: StorageAccessIF

INTERNAL: Called by the application when it requests a new object identity for a given object type.

Specified by:

generateIdentity in interface StorageAccessIF