fabric.store.db

Class BdbDB

java.lang.Object

fabric.store.db.ObjectDB

fabric.store.db.BdbDB

public class BdbDB
extends ObjectDB

An ObjectDB backed by a Berkeley Database.

Nested Class Summary

Nested classes/interfaces inherited from class fabric.store.db.ObjectDB

ObjectDB.PendingTransaction, ObjectDB.UpdateMode

Field Summary

Fields inherited from class fabric.store.db.ObjectDB

name, pendingByTid, rwLocks

Constructor Summary

Constructors

Constructor and Description
BdbDB(java.lang.String name, java.security.PrivateKey privateKey) Creates a new BdbStore for the store specified.

Method Summary

Modifier and Type	Method and Description
void	close() Clean up and close database.
void	commit(long tid, RemoteIdentity<RemoteWorker> workerIdentity, SubscriptionManager sm) Causes the objects prepared in transaction [tid] to be committed.
boolean	exists(long onum) Checks whether an object with the corresponding onum exists, in either prepared or committed form.
void	finishPrepare(long tid, Principal worker) Notifies the database that the given transaction is finished preparing.
int	getVersion(long onum) Returns the version number on the object stored at a particular onum.
boolean	isInitialized() Determines whether the object database has been initialized.
static void	main(java.lang.String[] args) Dumps the contents of a BDB object database to stdout.
long[]	newOnums(int num) Returns a set of onums that aren't currently occupied.
SerializedObject	read(long onum) Returns the object stored at a particular onum.
void	rollback(long tid, Principal worker) Causes the objects prepared in transaction [tid] to be discarded.
void	setInitialized() Sets a flag to indicate that the object database has been initialized.

Methods inherited from class fabric.store.db.ObjectDB

abortPrepare, beginTransaction, ensureInit, getName, isPrepared, isWritten, notifyCommittedUpdate, prepareRead, prepareUpdate, readGroup, unpin

Methods inherited from class java.lang.Object

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

Constructor Detail

BdbDB

public BdbDB(java.lang.String name,
             java.security.PrivateKey privateKey)

Creates a new BdbStore for the store specified. A new database will be created if it does not exist.

Parameters:

name - name of store to create store for.

Method Detail

finishPrepare

public void finishPrepare(long tid,
                          Principal worker)

Description copied from class: ObjectDB

Notifies the database that the given transaction is finished preparing. The transaction is not considered to be prepared until this is called. After calling this method, there should not be any further calls to registerRead() or registerUpdate() for the given transaction. This method MUST be called before calling commit().

Upon receiving this call, the object database should save the prepared transaction to stable storage so that it can be recovered in case of failure.

Specified by:

finishPrepare in class ObjectDB

commit

public void commit(long tid,
                   RemoteIdentity<RemoteWorker> workerIdentity,
                   SubscriptionManager sm)

Description copied from class: ObjectDB

Causes the objects prepared in transaction [tid] to be committed. The changes will hereafter be visible to read.

Specified by:

commit in class ObjectDB

Parameters:

tid - the transaction id

workerIdentity - the remote worker that is performing the commit

rollback

public void rollback(long tid,
                     Principal worker)

Description copied from class: ObjectDB

Causes the objects prepared in transaction [tid] to be discarded.

Specified by:

rollback in class ObjectDB

Parameters:

tid - the transaction id

worker - the principal requesting the rollback

read

public SerializedObject read(long onum)

Description copied from class: ObjectDB

Returns the object stored at a particular onum.

Specified by:

read in class ObjectDB

Parameters:

onum - the identifier

Returns:

the object or null if no object exists at the given onum

getVersion

public int getVersion(long onum)
               throws AccessException

Description copied from class: ObjectDB

Returns the version number on the object stored at a particular onum.

Overrides:

getVersion in class ObjectDB

Throws:

AccessException - if no object exists at the given onum.

exists

public boolean exists(long onum)

Description copied from class: ObjectDB

Checks whether an object with the corresponding onum exists, in either prepared or committed form.

Specified by:

exists in class ObjectDB

Parameters:

onum - the onum of to check

Returns:

true if an object exists for onum

newOnums

public long[] newOnums(int num)

Description copied from class: ObjectDB

Returns a set of onums that aren't currently occupied. The ObjectDB may return the same onum more than once from this method, althogh doing so would encourage collisions. There is no assumption of unpredictability or randomness about the returned ids.

The returned onums should be packed in the lower 48 bits. We assume that the object database is never full, and can always provide new onums

Specified by:

newOnums in class ObjectDB

Parameters:

num - the number of onums to return

Returns:

num fresh onums

close

public void close()

Clean up and close database.

Specified by:

close in class ObjectDB

isInitialized

public boolean isInitialized()

Description copied from class: ObjectDB

Determines whether the object database has been initialized.

Specified by:

isInitialized in class ObjectDB

setInitialized

public void setInitialized()

Description copied from class: ObjectDB

Sets a flag to indicate that the object database has been initialized.

Specified by:

setInitialized in class ObjectDB

main

public static void main(java.lang.String[] args)

Dumps the contents of a BDB object database to stdout.