/*
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
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.sparse;
import com.bigdata.btree.IIndex;
/**
* Atomic read of the logical row associated with some {@link Schema} and
* primary key.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
*/
public class AtomicRowRead extends AbstractAtomicRowReadOrWrite {
/**
*
*/
private static final long serialVersionUID = 7240920229720302721L;
@Override
public final boolean isReadOnly() {
return true;
}
/**
* De-serialization ctor.
*/
public AtomicRowRead() {
}
/**
* Constructor for an atomic read operation.
*
* @param schema
* The schema governing the property set.
* @param primaryKey
* The value of the primary key (identifies the logical row
* to be read).
* @param fromTime
* <em>During pre-condition and post-condition reads</em>, the
* first timestamp for which timestamped property values will be
* accepted.
* @param toTime
* <em>During pre-condition and post-condition reads</em>, the
* first timestamp for which timestamped property values will NOT
* be accepted -or- {@link IRowStoreConstants#CURRENT_ROW} to
* accept only the most current binding whose timestamp is GTE
* <i>fromTime</i>.
* @param filter
* An optional filter used to restrict the property values
* that will be returned.
*/
public AtomicRowRead(final Schema schema, final Object primaryKey,
final long fromTime, final long toTime, final INameFilter filter) {
super(schema, primaryKey, fromTime, toTime, filter);
}
/**
* Atomic read.
*
* @return A {@link TPS} instance containing the selected data from the
* logical row identified by the {@link #primaryKey} -or-
* <code>null</code> iff the primary key was NOT FOUND in the
* index. I.e., iff there are NO entries for that primary key
* regardless of whether or not they were selected.
*/
@Override
public TPS apply(final IIndex ndx) {
return atomicRead(ndx, schema, primaryKey, fromTime, toTime,
0L/* writeTime */, filter);
}
}