overflowdb

Class ReferenceManager

java.lang.Object

overflowdb.ReferenceManager

All Implemented Interfaces:

java.lang.AutoCloseable

public class ReferenceManager
extends java.lang.Object
implements java.lang.AutoCloseable

can clear references to disk and apply backpressure when creating new nodes, both to avoid an OutOfMemoryError can save all references to disk to persist the graph on shutdown n.b. we could also persist the graph without a ReferenceManager, by serializing all nodes to disk. But if that instance has been started from a storage location, the ReferenceManager ensures that we don't re-serialize all unchanged nodes.

Field Summary

Fields

Modifier and Type	Field and Description
int	releaseCount

Constructor Summary

Constructors

Constructor and Description
ReferenceManager(OdbStorage storage)

Method Summary

Modifier and Type	Method and Description
void	applyBackpressureMaybe() when we're running low on heap memory we'll serialize some elements to disk.
void	clearAllReferences() writes all references to disk overflow, blocks until complete.
void	close()
void	notifyHeapAboveThreshold()
void	registerRef(NodeRef ref)

Methods inherited from class java.lang.Object

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

Field Detail

releaseCount

public final int releaseCount

See Also:

Constant Field Values

Constructor Detail

ReferenceManager

public ReferenceManager(OdbStorage storage)

Method Detail

registerRef

public void registerRef(NodeRef ref)

applyBackpressureMaybe

public void applyBackpressureMaybe()

when we're running low on heap memory we'll serialize some elements to disk. to ensure we're not creating new ones faster than old ones are serialized away, we're applying some backpressure in those situation

notifyHeapAboveThreshold

public void notifyHeapAboveThreshold()

clearAllReferences

public void clearAllReferences()

writes all references to disk overflow, blocks until complete. useful when saving the graph

close

public void close()

Specified by:

close in interface java.lang.AutoCloseable