com.bigdata.journal.DropIndexTask 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.journal;
/**
* Drop a named index (unisolated write operation).
*
* Note: the dropped index will continue to be visible to unisolated readers or
* read-commmitted isolated operations (since they read from the most recent
* committed state) until the next commit. However, unisolated writers that
* execute after the index has been dropped will NOT be able to see the index.
*
* @author Bryan Thompson
*
* @see RegisterIndexTask
*/
public class DropIndexTask extends AbstractTask {
public DropIndexTask(final IConcurrencyManager concurrencyManager,
final String name) {
super(concurrencyManager, ITx.UNISOLATED, name);
}
/**
* Drop the named index.
*
* @return A {@link Boolean} value that is true iff the index
* was pre-existing at the time that this task executed and
* therefore was dropped. false is returned iff the
* index did not exist at the time that this task was executed.
*/
@Override
public Boolean doTask() throws Exception {
final String name = getOnlyResource();
try {
getJournal().dropIndex(name);
} catch (NoSuchIndexException ex) {
/*
* The index does not exist.
*/
log.warn("Index does not exist: " + name);
return Boolean.FALSE;
}
return Boolean.TRUE;
}
}