com.bigdata.sparse.IRowStoreConstants Maven / Gradle / Ivy
/*
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
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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
*/
/*
* Created on Oct 10, 2008
*/
package com.bigdata.sparse;
import com.bigdata.sparse.TPS.TPV;
/**
* Various constants that may be used with the {@link SparseRowStore}.
*
* @author Bryan Thompson
* @version $Id$
*/
public interface IRowStoreConstants {
/**
* The minimum value for a timestamp. This may be used as the fromTime
* to accept {@link TPV}s beginning with the earliest values on record in
* the store.
*/
public static final long MIN_TIMESTAMP = 1L;
/**
* The maximum value for a timestamp. This may be used as the toTime
* to accept {@link TPV}s up to the most current on record in the store.
*/
public static final long MAX_TIMESTAMP = Long.MAX_VALUE;
/**
* A special value that may be used as the toTime to read
* only the current values for a given logical row.
*
* Note: This value MAY NOT be specified for the fromTime. The
* fromTime is always the first timestamp that will be accepted by a
* read.
*
* Normally you will specify {@link #MIN_TIMESTAMP} as the fromTime
* when you specify {@link #CURRENT_ROW} as the toTime. This has the
* effect of returning the most current bindings for all properties in the
* logical row.
*
* If you specify a different fromTime timestamp then any property
* not bound since the given fromTime WILL NOT have a binding in the
* returned property set. This is useful when you are storing timeseries
* data as you can efficiently select a range of the timeseries.
*/
public static final long CURRENT_ROW = Long.MIN_VALUE;
/**
* A value which indicates that the timestamp will be assigned by the server -
* unique timestamps are NOT guaranteed with this constant. If the server
* assigns the same timestamp to two different writes on the same property
* values then only one of those property values will be persisted in the
* index - the other will be overwritten since it will have
* exactly the same key in the index. For this reason, you SHOULD use
* {@link #AUTO_TIMESTAMP_UNIQUE} unless you have a compelling reason and a
* robust design that is safe in the face of such possible overwrites.
*
* @see #AUTO_TIMESTAMP_UNIQUE
*/
public static final long AUTO_TIMESTAMP = -1L;
/**
* A value which indicates that a unique timestamp will be assigned by the
* server. You should use this value rather than {@link #AUTO_TIMESTAMP}
* unless you have a compelling design that is robust in the face of
* possible overwrite by other callers resulting in the assignment of
* the same timestamp to two different writes.
*
* @see #AUTO_TIMESTAMP
*/
public static final long AUTO_TIMESTAMP_UNIQUE = -2L;
}