com.bigdata.rdf.internal.encoder.IBindingSetEncoder 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
*/
/*
* Created on Feb 16, 2012
*/
package com.bigdata.rdf.internal.encoder;
import com.bigdata.bop.IBindingSet;
import com.bigdata.rdf.internal.IV;
import com.bigdata.rdf.internal.IVCache;
import com.bigdata.rdf.internal.IVUtility;
import com.bigdata.rdf.model.BigdataValue;
/**
* Interface for encoding {@link IBindingSet}s comprised of {@link IV}s. The
* interface is slightly more complicated than it otherwise would be due to (a)
* {@link IVCache} and (b) the need to vector operations.
*
* Encoding schemes tend to rely on {@link IVUtility} to provide fast and
* efficient encode / decode. This is the same representation which is used in
* the statement indices.
*
* The {@link IVCache} interface may be used to associate a materialized
* {@link BigdataValue} with an {@link IV}. In order to have efficient encode /
* decode of {@link IV}s which preserves the {@link IVCache} information, the
* encoding scheme also needs to store this association somewhere.
*
* Encoders designed for the wire should store the {@link IVCache} association
* in an inline representation. Encoders designed for main memory (for example,
* vectored operations in hash joins) can use persistence capable data
* structures to store the {@link IVCache} association.
*
* @author Bryan Thompson
* @version $Id$
* @see IBindingSetDecoder
*/
public interface IBindingSetEncoder {
/**
* Return true iff the {@link IVCache} associations are
* preserved by the encoder.
*/
boolean isValueCache();
/**
* Encode the solution as an {@link IV}[], collecting updates for the
* internal {@link IV} to {@link BigdataValue} cache.
*
* @param bset
* The solution to be encoded.
*
* @return The encoded solution.
*/
byte[] encodeSolution(final IBindingSet bset);
/**
* Encode the solution as an {@link IV}[].
*
* Note: The {@link IVCache} associations may be buffered by this method.
* Use {@link #flush()} to vector any buffered associations.
*
* @param bset
* The solution to be encoded.
* @param updateCache
* When true, updates are accumulated for the
* {@link IV} to {@link BigdataValue} cache. You must still use
* {@link #flush()} to vector the accumulated updates.
*
* If you are only generating the encoding in order to resolve a
* key in a hash index, then you would use false
* since you do not need to maintain the {@link IVCache}
* association for the given {@link IBindingSet}.
*
* @return The encoded solution.
*/
byte[] encodeSolution(final IBindingSet bset, final boolean updateCache);
/**
* Flush any updates. This allows for vectored operations when updating the
* {@link IVCache} associations.
*/
void flush();
/**
* Release the state associated with the {@link IVBindingSetEncoder}.
*/
void release();
}