com.bigdata.rdf.sail

Class RDRHistory

java.lang.Object

com.bigdata.rdf.sail.RDRHistory

All Implemented Interfaces:

IChangeLog

Direct Known Subclasses:

TestRDRHistory.CustomRDRHistory

public class RDRHistory
extends Object
implements IChangeLog

This is an experimental feature that captures history using the change log mechanism and RDR. For each relevant change event (subclasses can decide relevance), a new triple is added to the database, where the subject is the original statement, the predicate is the change action (added or removed), and the object is the commit time.

 << <s> <p> <o> >> <added>/<removed> "commitTime"^^xsd:long .
 
 

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	RDRHistory.Vocab Vocab terms to use for the "added" and "removed" predicates.

Field Summary

Fields

Modifier and Type	Field and Description
protected com.bigdata.rdf.sail.RDRHistory.Buffer	buffer The spo buffer backed by the temp store.
protected AbstractTripleStore	database The database.
protected TempTripleStore	tempStore The temp store used to hold change records until the commit.

Constructor Summary

Constructors

Constructor and Description
RDRHistory(AbstractTripleStore database)

Method Summary

Methods

Modifier and Type	Method and Description
protected boolean	accept(IChangeRecord record) Subclasses can override this to only record history on certain change events.
void	changeEvent(IChangeRecord record) Write the change record to the temp store.
void	close() Close out the temp store.
protected com.bigdata.rdf.sail.RDRHistory.Buffer	getOrCreateBuffer() Get the buffer, create it if necessary.
void	init() Give subclasses the opportunity for any initialization, including obtaining the IVs for the "added" and "removed" terms.
TempTripleStore	newTempTripleStore() Stolen from TruthMaintenance.newTempTripleStore().
protected IV<?,?>[]	resolveTerms(org.openrdf.model.URI[] terms) Helper method to resolve added and removed terms.
void	transactionAborted() Close out the temp store.
void	transactionBegin() Noop.
void	transactionCommited(long commitTime) Copy the statements from the temp store into the database, replacing the object position of each statement with the commit time, then close out the temp store.
void	transactionPrepare() Noop.

Methods inherited from class java.lang.Object

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

Field Detail

database

protected final AbstractTripleStore database

The database.

tempStore

protected TempTripleStore tempStore

The temp store used to hold change records until the commit.

buffer

protected com.bigdata.rdf.sail.RDRHistory.Buffer buffer

The spo buffer backed by the temp store.

Constructor Detail

RDRHistory

public RDRHistory(AbstractTripleStore database)

Method Detail

init

public void init()

Give subclasses the opportunity for any initialization, including obtaining the IVs for the "added" and "removed" terms.

resolveTerms

protected IV<?,?>[] resolveTerms(org.openrdf.model.URI[] terms)
                          throws Exception

Helper method to resolve added and removed terms.

Throws:

Exception

newTempTripleStore

public TempTripleStore newTempTripleStore()

Stolen from TruthMaintenance.newTempTripleStore().

changeEvent

public void changeEvent(IChangeRecord record)

Write the change record to the temp store.

Specified by:

changeEvent in interface IChangeLog

Parameters:

record - the IChangeRecord

accept

protected boolean accept(IChangeRecord record)

Subclasses can override this to only record history on certain change events.

Parameters:

record - change event

Returns:

true if history should be recorded

getOrCreateBuffer

protected com.bigdata.rdf.sail.RDRHistory.Buffer getOrCreateBuffer()

Get the buffer, create it if necessary.

transactionBegin

public void transactionBegin()

Noop.

Specified by:

transactionBegin in interface IChangeLog

transactionPrepare

public void transactionPrepare()

Noop.

Specified by:

transactionPrepare in interface IChangeLog

transactionCommited

public void transactionCommited(long commitTime)

Copy the statements from the temp store into the database, replacing the object position of each statement with the commit time, then close out the temp store.

Specified by:

transactionCommited in interface IChangeLog

Parameters:

commitTime - The timestamp associated with the commit point.

transactionAborted

public void transactionAborted()

Close out the temp store.

Specified by:

transactionAborted in interface IChangeLog

close

public void close()

Close out the temp store.

Specified by:

close in interface IChangeLog