de.schwarzrot.data.access
Interface EntityManager

All Known Implementing Classes:

AbstractEntityManager, JDBCEntityManager, NullEntityManager, PreferencesEntityManager

public interface EntityManager

is a manger to handle retrieval, saving and removal of entities to/from persistence.

The EntityManager is not intended for direct application usage. Use ApplicationTransactions, which will use internal Repository.

An EntityManager get's injected into repository by application-context.

Each EntityManager is related to a Class it works on. The EntityManager should also be able to handle all subclasses of that Class.

Author:

Reinhard Mantey

See Also:

Repository

Method Summary

void	commit(TransactionResource<?> resource) used to persist all changes made during transaction.
TransactionResource<?>	createTransactionResource(Transaction t) create an abstract handle to storage.
void	dumpTypeCache() for debugging purpose only.
void	execute(TransactionalOperation<?> tao) execute a single step of ApplicationTransaction
String	getApplicationName() returns the name of the application
EntityDescriptor	getEntityDescriptor(Class<?> entityType, TransactionResource<?> res) accessor to description instances of entities.
String	getSchemaName(Class<?> entityType, TransactionResource<?> resource) returns the schema name, used by entities of given type and given storage
void	releaseTransactionResource(TransactionResource<?> resource) free given storage handle
void	rollback(TransactionResource<?> handle) discards changes of given storage handle and marks Transaction as failed.
void	setEntityCache(EntityHolder eh) sets the cache for entity instances
void	setEntityIntrospector(EntityIntrospector entityIntrospector) sets the entity introspector used to fill an EntityDescriptor with informations about entities.
void	setSchemaName(Class<?> entityType, String schema, TransactionResource<?> resource) sets the schema name to use by instances of given entity and resource
void	setUserNameProvider(UserNameProvider unp) sets the username provider used by this EntityManager

Method Detail

commit

void commit(TransactionResource<?> resource)
            throws Exception

used to persist all changes made during transaction.

Parameters:

resource - - an abstract handle to storage

Throws:

Exception - - depends on implementation

createTransactionResource

TransactionResource<?> createTransactionResource(Transaction t)
                                                 throws Exception

create an abstract handle to storage. TransactionResource is a wrapper to handle jdbc and preferences the same way.

Parameters:

t - - the transaction

Returns:

- a wrapped storage handle

Throws:

Exception - - depends on implementation

dumpTypeCache

void dumpTypeCache()

for debugging purpose only. Dumps out all known entities of that EntityManager.

execute

void execute(TransactionalOperation<?> tao)
             throws Exception

execute a single step of ApplicationTransaction

Parameters:

tao - - the transactional operation to execute

Throws:

Exception - - depends on implementation

getApplicationName

String getApplicationName()

returns the name of the application

Returns:

- the name of the application

getEntityDescriptor

EntityDescriptor getEntityDescriptor(Class<?> entityType,
                                     TransactionResource<?> res)

accessor to description instances of entities. An EntityDescriptor holds all information needed by an EntityManager to handle instances of that entity. The EntityDescriptor may vary between different EntityManager s.

Parameters:

entityType - - the class of that entity

res - - the wrapped storage handle

Returns:

- the descriptor for that entity

getSchemaName

String getSchemaName(Class<?> entityType,
                     TransactionResource<?> resource)

returns the schema name, used by entities of given type and given storage

Parameters:

entityType - - the class of entity

resource - - the wrapped storage handle

Returns:

- the schema name to use

releaseTransactionResource

void releaseTransactionResource(TransactionResource<?> resource)

free given storage handle

Parameters:

resource - - a wrapped storage handle

rollback

void rollback(TransactionResource<?> handle)

discards changes of given storage handle and marks Transaction as failed.

Parameters:

handle - - a wrapped storage handle

setEntityCache

void setEntityCache(EntityHolder eh)

sets the cache for entity instances

Parameters:

eh - - the cache handler

setEntityIntrospector

void setEntityIntrospector(EntityIntrospector entityIntrospector)

sets the entity introspector used to fill an EntityDescriptor with informations about entities.

Parameters:

entityIntrospector - - the introspector to use

setSchemaName

void setSchemaName(Class<?> entityType,
                   String schema,
                   TransactionResource<?> resource)

sets the schema name to use by instances of given entity and resource

Parameters:

entityType - - class of entity

schema - - the schema name

resource - - a wrapped storage handle

setUserNameProvider

void setUserNameProvider(UserNameProvider unp)

sets the username provider used by this EntityManager

Parameters:

unp - - the username provider to use