Package io.bdeploy.bhive.objects

Class MarkerDatabase

java.lang.Object

io.bdeploy.bhive.objects.LockableDatabase

io.bdeploy.bhive.objects.ObjectDatabase

io.bdeploy.bhive.objects.MarkerDatabase

public class MarkerDatabase
extends ObjectDatabase

A marker database acts as temporary synchronization and locking over threads and even JVMs.

An example are BHiveTransactions. They use a MarkerDatabase to "mark" each object written. As long as there is not manifest inserted in the BHive, these objects would be dangling, and subject to removal by prune. The PruneOperation takes into account any marked object by any transaction and does not touch them.

Nested Class Summary

Nested classes/interfaces inherited from class io.bdeploy.bhive.objects.LockableDatabase

LockableDatabase.LockedOperation

Constructor Summary

Constructors

Constructor	Description
MarkerDatabase(Path root, ActivityReporter reporter)

Method Summary

Modifier and Type	Method	Description
void	addMarker(ObjectId id)	Marks the given ObjectId.
InputStream	getStream(ObjectId id)	Retrieves an InputStream from which the actual content of an object with the given ObjectId can be read.
protected ObjectId	internalAddObject(ObjectWriter writer)
void	removeObject(ObjectId id)	Removes the given ObjectIds backing file from the database.

Methods inherited from class io.bdeploy.bhive.objects.ObjectDatabase

addObject, addObject, addObject, checkObject, getAllObjects, getObjectFile, getObjectSize, hasObject

Methods inherited from class io.bdeploy.bhive.objects.LockableDatabase

locked

Methods inherited from class java.lang.Object

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

Constructor Details

MarkerDatabase

public MarkerDatabase(Path root,
 ActivityReporter reporter)

Method Details

addMarker

public void addMarker(ObjectId id)

Marks the given ObjectId. The operation is thread-safe, but only if called with different ObjectId.

The caller(s) must make sure to call this method only once with any given ObjectId.

getStream

public InputStream getStream(ObjectId id)
                      throws IOException

Description copied from class: ObjectDatabase

Retrieves an InputStream from which the actual content of an object with the given ObjectId can be read.

Overrides:

getStream in class ObjectDatabase

Parameters:

id - the ObjectId of the object to lookup.

Returns:

an InputStream to the object.

Throws:

IOException - in case of an error.

internalAddObject

protected ObjectId internalAddObject(ObjectWriter writer)
                              throws IOException

Overrides:

internalAddObject in class ObjectDatabase

Throws:

IOException

removeObject

public void removeObject(ObjectId id)

Description copied from class: ObjectDatabase

Removes the given ObjectIds backing file from the database.

WARNING: use with care, this can cause corruption!

Overrides:

removeObject in class ObjectDatabase