org.exolab.castor.jdo.engine
Class DatabaseImpl

java.lang.Object
  org.exolab.castor.jdo.engine.DatabaseImpl

All Implemented Interfaces:

javax.transaction.Synchronization, Database

public class DatabaseImpl
extends java.lang.Object
implements Database, javax.transaction.Synchronization

An implementation of the JDO database supporting explicit transaction demarcation.

Version:

$Revision: 1.29 $ $Date: 2005/11/10 15:59:50 $

Author:

Assaf Arkin, Bruce Snyder

Field Summary

protected TransactionContext	_ctx The transaction context is this database was accessed with an XAResource.
protected PersistenceInfoGroup	_scope The database engine used to access the underlying SQL database.

Fields inherited from interface org.exolab.castor.jdo.Database

DbLocked, Exclusive, ReadOnly, Shared

Constructor Summary

DatabaseImpl(java.lang.String dbName, int lockTimeout, CallbackInterceptor callback, InstanceFactory instanceFactory, javax.transaction.Transaction transaction, java.lang.ClassLoader classLoader, boolean autoStore)

Method Summary

void	afterCompletion(int status)
void	beforeCompletion()
void	begin() Begin a new transaction.
void	close() Closes the database.
void	commit() Commits and closes the transaction.
void	create(java.lang.Object object) Creates a new object in persistent storage.
void	expireCache(java.lang.Class[] type, java.lang.Object[] identity) Deprecated. Please use the new CacheManager which can be obtained by calling getCacheManager().
protected void	finalize() Overrides Object.finalize().
CacheManager	getCacheManager() Get's the CacheManager instance.
java.lang.ClassLoader	getClassLoader() Gets the current application ClassLoader's instance.
java.lang.String	getDatabaseName() } Return the name of the database
java.lang.Object	getIdentity(java.lang.Object object) Returns the object's identity.
java.sql.Connection	getJdbcConnection() Get the underlying JDBC Connection.
(package private) LockEngine	getLockEngine()
OQLQuery	getOQLQuery() Creates an OQL query with no statement.
OQLQuery	getOQLQuery(java.lang.String oql) Creates an OQL query from the supplied statement.
Query	getQuery() Creates an empty query.
PersistenceInfoGroup	getScope()
protected TransactionContext	getTransaction()
boolean	isActive() Returns true if a transaction is currently active.
boolean	isAutoStore() Return if the current transaction is set to autoStore, it there is transaction active.
boolean	isClosed() Returns true if the database is closed.
boolean	isPersistent(java.lang.Object object) Returns true if the object is persistent.
java.lang.Object	load(java.lang.Class type, java.lang.Object identity) Load an object of the specified type and given identity.
java.lang.Object	load(java.lang.Class type, java.lang.Object identity, AccessMode mode) Load an object of the specified type and given identity.
java.lang.Object	load(java.lang.Class type, java.lang.Object identity, java.lang.Object object) Load an object of the specified type and given identity into a given instance of object.
java.lang.Object	load(java.lang.Class type, java.lang.Object identity, short accessMode) Load an object of the specified type and given identity.
void	lock(java.lang.Object object) Acquire a soft write lock on the object.
void	remove(java.lang.Object object) Removes the object from persistent storage.
void	rollback() Rolls back and closes the transaction.
void	setAutoStore(boolean autoStore) True if user prefer all reachable object to be stored automatically.
(package private) void	setTxMap(TxDatabaseMap txMap)
java.lang.String	toString()
void	update(java.lang.Object object) Update a data object which is queried/loaded/created in another transaction.

Methods inherited from class java.lang.Object

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

Field Detail

_scope

protected PersistenceInfoGroup _scope

The database engine used to access the underlying SQL database.

_ctx

protected TransactionContext _ctx

The transaction context is this database was accessed with an XAResource.

Constructor Detail

DatabaseImpl

public DatabaseImpl(java.lang.String dbName,
                    int lockTimeout,
                    CallbackInterceptor callback,
                    InstanceFactory instanceFactory,
                    javax.transaction.Transaction transaction,
                    java.lang.ClassLoader classLoader,
                    boolean autoStore)
             throws DatabaseNotFoundException

Throws:

DatabaseNotFoundException

Method Detail

getLockEngine

LockEngine getLockEngine()

getScope

public PersistenceInfoGroup getScope()

Specified by:

getScope in interface Database

setAutoStore

public void setAutoStore(boolean autoStore)

True if user prefer all reachable object to be stored automatically. False if user want only dependent object to be stored.

Specified by:

setAutoStore in interface Database

Parameters:

autoStore - True to indicate that 'autoStore' mode should be used.

isAutoStore

public boolean isAutoStore()

Return if the current transaction is set to autoStore, it there is transaction active. If there is no active transaction, return if the next transaction will be set to autoStore.

Specified by:

isAutoStore in interface Database

Returns:

True if 'auto-store' mode is in use.

getClassLoader

public java.lang.ClassLoader getClassLoader()

Gets the current application ClassLoader's instance. For use in OQLQueryImpl and TransactionContext.

Specified by:

getClassLoader in interface Database

Returns:

the current ClassLoader's instance, or null if not provided

getDatabaseName

public java.lang.String getDatabaseName()

} Return the name of the database

Specified by:

getDatabaseName in interface Database

Returns:

Name of the database.

close

public void close()
           throws PersistenceException

Description copied from interface: Database

Closes the database. If a client transaction is in progress the transaction will be rolled back and an exception thrown. If an app-server transaction is in progress, the transaction will commit/rollback when triggered by the application server.

Specified by:

close in interface Database

Throws:

PersistenceException - An error occured while attempting to close the database

isClosed

public boolean isClosed()

Description copied from interface: Database

Returns true if the database is closed.

Specified by:

isClosed in interface Database

Returns:

True if the database is closed

load

public java.lang.Object load(java.lang.Class type,
                             java.lang.Object identity)
                      throws ObjectNotFoundException,
                             LockNotGrantedException,
                             TransactionNotInProgressException,
                             PersistenceException

Description copied from interface: Database

Load an object of the specified type and given identity. Once loaded the object is persistent. Calling this method with the same identity in the same transaction will return the same object. This method is equivalent to a query that returns a single object. If the identity spans on more than one field, all of the identity fields can be wrapped in a Complex object.

Specified by:

load in interface Database

Parameters:

type - The object's type

identity - The object's identity

Returns:

The object instance.

Throws:

ObjectNotFoundException - No object of the given type and identity was found in persistent storage

LockNotGrantedException - Timeout or deadlock occured attempting to acquire a lock on the object

TransactionNotInProgressException - Method called while transaction is not in progress

PersistenceException - An error reported by the persistence engine

load

public java.lang.Object load(java.lang.Class type,
                             java.lang.Object identity,
                             java.lang.Object object)
                      throws TransactionNotInProgressException,
                             ObjectNotFoundException,
                             LockNotGrantedException,
                             PersistenceException

Description copied from interface: Database

Load an object of the specified type and given identity into a given instance of object. Once loaded the object is persistent. Calling this method with the same identity in the same transaction will return the same object. This method is equivalent to a query that returns a single object. If the identity spans on more than one field, all of the identity fields can be wrapped in a Complex object.

Specified by:

load in interface Database

Parameters:

type - The object's type

identity - The object's identity

object - The object instance to be loaded into

Returns:

The object instance.

Throws:

TransactionNotInProgressException - Method called while transaction is not in progress

ObjectNotFoundException - No object of the given type and identity was found in persistent storage

LockNotGrantedException - Timeout or deadlock occured attempting to acquire a lock on the object

PersistenceException - An error reported by the persistence engine

load

public java.lang.Object load(java.lang.Class type,
                             java.lang.Object identity,
                             short accessMode)
                      throws ObjectNotFoundException,
                             LockNotGrantedException,
                             TransactionNotInProgressException,
                             PersistenceException

Description copied from interface: Database

Load an object of the specified type and given identity. Once loaded the object is persistent. Calling this method with the same identity in the same transaction will return the same object. This method is equivalent to a query that returns a single object.

Specified by:

load in interface Database

Parameters:

type - The object's type

identity - The object's identity

accessMode - The access mode

Returns:

The object instance.

Throws:

ObjectNotFoundException - No object of the given type and identity was found in persistent storage

LockNotGrantedException - Timeout or deadlock occured attempting to acquire a lock on the object

TransactionNotInProgressException - Method called while transaction is not in progress

PersistenceException - An error reported by the persistence engine

load

public java.lang.Object load(java.lang.Class type,
                             java.lang.Object identity,
                             AccessMode mode)
                      throws TransactionNotInProgressException,
                             ObjectNotFoundException,
                             LockNotGrantedException,
                             PersistenceException

Description copied from interface: Database

Load an object of the specified type and given identity. Once loaded the object is persistent. Calling this method with the same identity in the same transaction will return the same object. This method is equivalent to a query that returns a single object.

Specified by:

load in interface Database

Parameters:

type - The object's type

identity - The object's identity

mode - The access mode

Returns:

The object instance.

Throws:

TransactionNotInProgressException - Method called while transaction is not in progress

ObjectNotFoundException - No object of the given type and identity was found in persistent storage

LockNotGrantedException - Timeout or deadlock occured attempting to acquire a lock on the object

PersistenceException - An error reported by the persistence engine

create

public void create(java.lang.Object object)
            throws ClassNotPersistenceCapableException,
                   DuplicateIdentityException,
                   TransactionNotInProgressException,
                   PersistenceException

Description copied from interface: Database

Creates a new object in persistent storage. The object will be persisted only if the transaction commits.

If the object has an identity then duplicate identity check happens in this method, and the object is visible to queries in this transaction. If the identity is null, duplicate identity check occurs when the transaction completes and the object is not visible to queries until the transaction commits.

Specified by:

create in interface Database

Parameters:

object - The object to create

Throws:

ClassNotPersistenceCapableException - The class is not persistent capable

DuplicateIdentityException - An object with this identity already exists in persistent storage

TransactionNotInProgressException - Method called while transaction is not in progress

PersistenceException - An error reported by the persistence engine

getCacheManager

public CacheManager getCacheManager()

Description copied from interface: Database

Get's the CacheManager instance. Call getCacheManager for every Database-instances.

Specified by:

getCacheManager in interface Database

Returns:

the CacheManager-instance.

See Also:

Database.getCacheManager()

update

public void update(java.lang.Object object)
            throws ClassNotPersistenceCapableException,
                   ObjectModifiedException,
                   TransactionNotInProgressException,
                   PersistenceException

Description copied from interface: Database

Update a data object which is queried/loaded/created in another transaction. This method is used only for long transaction support. Calling this method for data object queried/loaded/created in the same transaction results in Exception.

For example, the data object may be sent to a client application and dispayed to a user. After that the objects is being modified in the client application, the object returns back and is update to the database in the second transaction.

See Long Transaction on Castor website.

Specified by:

update in interface Database

Parameters:

object - The object to create

Throws:

ClassNotPersistenceCapableException - The class is not persistent capable

TransactionNotInProgressException - Method called while transaction is not in progress

PersistenceException - An error reported by the persistence engine

ObjectModifiedException

remove

public void remove(java.lang.Object object)
            throws ObjectNotPersistentException,
                   LockNotGrantedException,
                   TransactionNotInProgressException,
                   PersistenceException

Description copied from interface: Database

Removes the object from persistent storage. The deletion will take effect only if the transaction is committed, but the object is no longer visible to queries in the current transaction and locks for access from other transactions will block until this transaction completes.

Specified by:

remove in interface Database

Parameters:

object - The object to remove

Throws:

ObjectNotPersistentException - The object has not been queried or created in this transaction

LockNotGrantedException - Timeout or deadlock occured attempting to acquire a lock on the object

TransactionNotInProgressException - Method called while transaction is not in progress

PersistenceException - An error reported by the persistence engine

isPersistent

public boolean isPersistent(java.lang.Object object)

Description copied from interface: Database

Returns true if the object is persistent. An object is persistent if it was created or queried in this transaction. If the object was created or queried in another transaction, or there is no open transaction, this method returns null.

Specified by:

isPersistent in interface Database

Parameters:

object - The object

Returns:

True if persistent in this transaction

getIdentity

public java.lang.Object getIdentity(java.lang.Object object)
                             throws ClassNotPersistenceCapableException

Description copied from interface: Database

Returns the object's identity. The identity will be determined by calling the getters of the fields defined as identities in the mapping. If a mapping for the objects class could not be found a ClassNotPersistenceCapableException will be thrown. Null is only returned if the objects identity is null. It is not required to have an active transaction when using this method.

Note: Prior to 0.9.9.1 release of castor the identity could only be determined if the object took part in the transaction. If this was not the case, the previous implementation also returned null.

Specified by:

getIdentity in interface Database

Parameters:

object - The object.

Returns:

The object's identity, or null.

Throws:

ClassNotPersistenceCapableException - The class is not persistent capable.

lock

public void lock(java.lang.Object object)
          throws LockNotGrantedException,
                 ObjectNotPersistentException,
                 TransactionNotInProgressException,
                 PersistenceException

Description copied from interface: Database

Acquire a soft write lock on the object. Read locks are implicitly available when the object is queried. A write lock is only granted for objects that are created or deleted or for objects loaded in exclusive mode - this method can obtain such a lock explicitly.

A soft lock is acquired in memory, not in the database. To acquire a lock in the database, use the locked access mode.

If the object already has a write lock in this transaction or a read lock in this transaction but no read lock in any other transaction, a write lock is obtained. If this object has a read lock in any other transaction this method will block until the other transaction will release its lock. If the timeout has elapsed or a deadlock has been detected, an exception will be thrown but the current lock will be retained.

Specified by:

lock in interface Database

Parameters:

object - The object to lock

Throws:

LockNotGrantedException - Timeout or deadlock occured attempting to acquire a lock on the object

ObjectNotPersistentException - The object has not been queried or created in this transaction

TransactionNotInProgressException - Method called while transaction is not in progress

PersistenceException - An error reported by the persistence engine

getOQLQuery

public OQLQuery getOQLQuery()

Description copied from interface: Database

Creates an OQL query with no statement. OQLQuery.create(java.lang.String) must be called before the query can be executed.

Specified by:

getOQLQuery in interface Database

Returns:

An OQL query

getOQLQuery

public OQLQuery getOQLQuery(java.lang.String oql)
                     throws PersistenceException

Description copied from interface: Database

Creates an OQL query from the supplied statement.

Specified by:

getOQLQuery in interface Database

Parameters:

oql - An OQL query statement

Returns:

An OQL query

Throws:

PersistenceException

getQuery

public Query getQuery()

Description copied from interface: Database

Creates an empty query. The query must be created before it can be executed.

Specified by:

getQuery in interface Database

Returns:

A query

finalize

protected void finalize()
                 throws java.lang.Throwable

Overrides Object.finalize(). Outputs a warning message to teh logs if the current DatabaseImpl instance still has valid scope. In this condition - a condition that ideally should not occur at all - we close the instance as well to free up resources.

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable

See Also:

Object.finalize()

getTransaction

protected TransactionContext getTransaction()
                                     throws TransactionNotInProgressException

Throws:

TransactionNotInProgressException

begin

public void begin()
           throws PersistenceException

Description copied from interface: Database

Begin a new transaction. A transaction must be open in order to query and persist objects.

Specified by:

begin in interface Database

Throws:

PersistenceException - A transaction is already open on this database, or an error reported by the persistence engine

commit

public void commit()
            throws TransactionNotInProgressException,
                   TransactionAbortedException

Description copied from interface: Database

Commits and closes the transaction. All changes made to persistent objects during the transaction are made persistent; objects created during the transaction are made durable; and, objects removed during the transaction are removed from the database.

In other words, any modifications to any data objects which are queried/loaded/created/update to this database is automatically stored to the database and visible to subsequence transactions. (ie. update is solely used for long transaction support and should not be called for any data object queried/loaded/created in the this transaction.)

If the transaction cannot commit, the entire transaction rolls back and a TransactionAbortedException exception is thrown.

After this method returns, the transaction is closed and all persistent objects are transient. Using Database.begin() to open a new transaction will not restore objects to their persistent stage.

Specified by:

commit in interface Database

Throws:

TransactionNotInProgressException - Method called while transaction is not in progress

TransactionAbortedException - The transaction cannot commit and has been rolled back

rollback

public void rollback()
              throws TransactionNotInProgressException

Description copied from interface: Database

Rolls back and closes the transaction. All changes made to persistent objects during the transaction are lost, objects created during the transaction are not made durable and objects removed during the transaction continue to exist.

Specified by:

rollback in interface Database

Throws:

TransactionNotInProgressException - Method called while transaction is not in progress

beforeCompletion

public void beforeCompletion()

Specified by:

beforeCompletion in interface javax.transaction.Synchronization

afterCompletion

public void afterCompletion(int status)

Specified by:

afterCompletion in interface javax.transaction.Synchronization

setTxMap

void setTxMap(TxDatabaseMap txMap)

isActive

public boolean isActive()

Description copied from interface: Database

Returns true if a transaction is currently active.

Specified by:

isActive in interface Database

Returns:

True if a transaction is active

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getJdbcConnection

public java.sql.Connection getJdbcConnection()
                                      throws PersistenceException

Get the underlying JDBC Connection. This is for advanced use only. Please make sure that you never close this Connection instance, as it will be closed by Castor.

Specified by:

getJdbcConnection in interface Database

Returns:

the underlying JDBC connection, if possible

Throws:

PersistenceException - If the underlying JDBC connection cannot be obtained.

expireCache

public void expireCache(java.lang.Class[] type,
                        java.lang.Object[] identity)
                 throws PersistenceException

Deprecated. Please use the new CacheManager which can be obtained by calling getCacheManager().

Expire objects from the cache. Objects expired from the cache will be read from persistent storage, as opposed to being read from the performance cache, during subsequent load/query operations. Objects may be expired from the cache individually, using explicit type/identity pairs in the argument list, or whole classes of objects may be expired by specifying a class type without a corresponding entry in the identity array. Objects contained within a "master" object, for example objects maintained in a one-to-many relationship, will automatically be expired from the cache without the need to explicitly identify them. This does not apply when expiring objects by type. Each type, both container and contained objects need to be specified.

Parameters:

type - An array of class types.

identity - An array of object identifiers.

Throws:

PersistenceException - Indicates that a problem has occured expiring objects from the cache.