org.apache.jackrabbit.mk.persistence
Interface GCPersistence

All Superinterfaces:

Closeable, Persistence

All Known Implementing Classes:

H2Persistence, InMemPersistence

public interface GCPersistence
extends Persistence

Advanced persistence implementation offering GC support.

The persistence implementation must ensure that objects written between start() and sweep() are not swept, in other words, they must be marked implicitely.

Method Summary

boolean	markCNEMap(Id id) Mark a child node entry map.
boolean	markCommit(Id id) Mark a commit.
boolean	markNode(Id id) Mark a node.
void	replaceCommit(Id id, Commit commit) Replace a commit.
void	start() Start a GC cycle.
int	sweep() Sweep all objects that are not marked and were written before the GC started.

Methods inherited from interface org.apache.jackrabbit.mk.persistence.Persistence

initialize, readCNEMap, readCommit, readIds, readNode, writeCNEMap, writeCommit, writeHead, writeNode

Methods inherited from interface java.io.Closeable

close

Method Detail

start

void start()

Start a GC cycle. All objects written to the persistence in subsequent calls are marked implicitely, i.e. they must be retained on sweep().

markCommit

boolean markCommit(Id id)
                   throws Exception

Mark a commit.

Parameters:

id - commit id

Returns:

true if the commit was not marked before; false otherwise

Throws:

Exception - if an error occurs

replaceCommit

void replaceCommit(Id id,
                   Commit commit)
                   throws Exception

Replace a commit. Introduced to replace dangling parent commits where a parent commit might be collected.

Parameters:

id - commit id

-

Throws:

Exception - if an error occurs

markNode

boolean markNode(Id id)
                 throws Exception

Mark a node.

Parameters:

id - node id

Returns:

true if the node was not marked before; false otherwise

Throws:

Exception - if an error occurs

markCNEMap

boolean markCNEMap(Id id)
                   throws Exception

Mark a child node entry map.

Parameters:

id - child node entry map id

Returns:

true if the child node entry map was not marked before; false otherwise

Throws:

Exception - if an error occurs

sweep

int sweep()
          throws Exception

Sweep all objects that are not marked and were written before the GC started.

Returns:

number of swept items or -1 if number is unknown

Throws:

Exception - if an error occurs