com.bigdata.ha.msg.IHARootBlockRequest Maven / Gradle / Ivy
/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
[email protected]
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.bigdata.ha.msg;
import java.util.UUID;
/**
* Message requesting a root block for a store on a remote service.
*/
public interface IHARootBlockRequest extends IHAMessage {
/**
* The {@link UUID} of the journal whose root block will be returned
* (optional, defaults to the current Journal).
*
* Note: This parameter is intended for scale-out if there is a need to
* fetch the root block of a historical journal (versus the live journal).
*/
UUID getStoreUUID();
/**
* When true the request should be non-blocking. Otherwise the
* request should obtain the lock that guards the update of the root block
* in the commit protocol such that the caller can not observe a root block
* that has been updated but where the commit protocol is still in its
* critical section.
*
* Note: The non-blocking form of the request is used in some context where
* the avoidence of a deadlock is necessary. The blocking form is used in
* some contexts where we need to await a specific commit point on the
* service (typically under test suite control).
*/
boolean isNonBlocking();
}