cern.entwined

Class SemiPersistent<T>

java.lang.Object

cern.entwined.SemiPersistent<T>

Type Parameters:

T - The implementation collection type.

Direct Known Subclasses:

CompositeCollection, Snapshot, TransactionalMap, TransactionalMultimap, TransactionalQueue, TransactionalRef

public abstract class SemiPersistent<T>
extends Object

The root to all the transactionally manged collections.

Author:

Ivan Koblik

Constructor Summary

Constructors

Constructor and Description
SemiPersistent()

Method Summary

Methods

Modifier and Type	Method and Description
protected abstract T	cleanCopy() Creates a new transactional entity from the current one discarding all the local changes.
T	commit(T globalState) Performs conflict checks and if no conflicts detected returns new instance with all the pending changes applied.
protected abstract T	dirtyCopy() Copies references to the source data along with local changes and read/write logs.
protected abstract void	update(T changes, boolean onlyReadLogs) Updates local changes and change logs using change logs of the arguments.

Methods inherited from class java.lang.Object

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

Constructor Detail

SemiPersistent

public SemiPersistent()

Method Detail

cleanCopy

protected abstract T cleanCopy()

Creates a new transactional entity from the current one discarding all the local changes.

Returns:

The new entity with no local changes.

dirtyCopy

protected abstract T dirtyCopy()

Copies references to the source data along with local changes and read/write logs.
Note: It is very important to copy source data by reference, otherwise SemiPersistent#update(Object) will not work.

Returns:

Dirty copy of this collection, with all the local changes and read/write logs preserved.

update

protected abstract void update(T changes,
          boolean onlyReadLogs)

Updates local changes and change logs using change logs of the arguments. Argument must be constructed from this using dirtyCopy().
Note: Any changes done to this collections after branching will be discarded.

Parameters:

changes - The branched collection possibly with updates.

onlyReadLogs - If true only read logs are updated. Useful for read-only transactions.

commit

public T commit(T globalState)

Performs conflict checks and if no conflicts detected returns new instance with all the pending changes applied.

Parameters:

globalState - The current system's global state.

Returns:

New instance with all the pending changes applied.

Throws:

ConflictException - When conflicting changes detected.