sos.db
Interface TransactionSupport

public interface TransactionSupport

An auxiliary class that allows a TransactionPolicy to register commit and abort actions and to signal that an object's state has changed.

Since:

1.0

See Also:

TransactionPolicy

Method Summary

void	addAbortAction(java.lang.Runnable action) Registers an action to be run when the transaction aborts.
void	addCommitAction(java.lang.Runnable action) Registers an action to be run when the top-level transaction commits.
Database	getDatabase() Returns the database for which this transaction is occurring.
java.lang.Object	getKey() Returns a key that uniquely identifies the object.
java.lang.Object	getObjectForRead() Prepares and returns the object for reading.
java.lang.Object	getObjectForWrite() Prepares and returns the object for writing.
java.lang.Object	getProxy() Returns the database proxy object overseeing the object.
void	notifyChanged(java.lang.Object object, boolean garbagePossible) Informs the transaction that the object's state has changed and the object needs to be resaved in the database.

Method Detail

addCommitAction

void addCommitAction(java.lang.Runnable action)

Registers an action to be run when the top-level transaction commits.

Parameters:

action - code to be executed when the top-level transaction commits

Throws:

java.lang.NullPointerException - if action is null

addAbortAction

void addAbortAction(java.lang.Runnable action)

Registers an action to be run when the transaction aborts.

Parameters:

action - code to be executed when the transaction aborts

Throws:

java.lang.NullPointerException - if action is null

getDatabase

Database getDatabase()

Returns the database for which this transaction is occurring.

Returns:

the database for which ths transaction is occurring

getKey

java.lang.Object getKey()

Returns a key that uniquely identifies the object. It is safe to invoke hashCode, equals, and toString on the returned key.

Returns:

a non-null object that uniquely identifies the object

getObjectForRead

java.lang.Object getObjectForRead()
                                  throws java.io.IOException

Prepares and returns the object for reading.

Returns:

the object that can be read

Throws:

java.io.IOException - if an I/O error occurs

getObjectForWrite

java.lang.Object getObjectForWrite()
                                   throws java.io.IOException

Prepares and returns the object for writing.

Returns:

the object that can be written to

Throws:

java.io.IOException - if an I/O error occurs

getProxy

java.lang.Object getProxy()

Returns the database proxy object overseeing the object.

Returns:

the object's proxy

Since:

1.2

notifyChanged

void notifyChanged(java.lang.Object object,
                   boolean garbagePossible)
                   throws java.io.IOException

Informs the transaction that the object's state has changed and the object needs to be resaved in the database.

Parameters:

object - the modified object

garbagePossible - true if the object has changed in such a way that previously reachable database object may now be unreachable

Throws:

java.lang.IllegalStateException - if this database is open in read-only mode

java.io.IOException - if an I/O error occurs