com.bigdata.bop.solutions.ISolutionSet Maven / Gradle / Ivy
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/**
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 Apr 9, 2012
*/
package com.bigdata.bop.solutions;
import com.bigdata.bop.IBindingSet;
import com.bigdata.bop.controller.INamedSolutionSetRef;
import com.bigdata.btree.BTree;
import com.bigdata.btree.ICheckpointProtocol;
import com.bigdata.htree.HTree;
import com.bigdata.rdf.sparql.ast.ISolutionSetStats;
import com.bigdata.relation.accesspath.AccessPath;
import com.bigdata.relation.accesspath.IAccessPath;
import com.bigdata.stream.Stream;
import cutthecrap.utils.striterators.ICloseableIterator;
/**
* Interface for durable solution sets.
*
* @author Bryan Thompson
*
* TODO Provide {@link ISolutionSet} implementations derived from
* {@link HTree} and {@link BTree}.
*
* I am not sure that we will require this. We can probably use the
* {@link SolutionSetStream} for named solution sets for quite a while
* without supporting declaration of named solution sets with specific
* join variables. However, if we do add support for this, then we need
* to reconcile the {@link HTree} version with the hash join code and
* {@link INamedSolutionSetRef} and also add an {@link IAccessPath} for
* {@link HTree} and {@link Stream} backed solution sets so they can be
* played out through a simple iterator model. The {@link AccessPath} is
* relation specific, but it could be relayered to provide support for
* the {@link BTree} backed solution sets.
*/
public interface ISolutionSet extends ICheckpointProtocol {
/**
* Return the {@link ISolutionSetStats} for the saved solution set. This may
* be used for query planning and should not require the backing solutions
* to be materialized.
*
* @return The {@link ISolutionSetStats}.
*/
public ISolutionSetStats getStats();
// /**
// * Return the CREATE schema for the solution set (this is the metadata used
// * to provision the characteristics of the solution set).
// *
// * TODO This should be stored in a "root" on the checkpoint record.
// */
// public ISPO[] getDeclation();
/**
* Visit all entries in the index in the natural order of the index.
*/
public ICloseableIterator scan();
/**
* Return an {@link ICloseableIterator} reading the solutions from the
* stream.
*/
public ICloseableIterator get();
/**
* Replace the contents of the stream with the solutions read from the
* source.
*
* @param src
* The source.
*/
public void put(final ICloseableIterator src);
// /**
// * The {@link IVariable[]} specifying the join variables (required). The
// * order of the entries is used when forming the as-bound keys for the hash
// * table. Duplicate elements and null elements are not permitted.
// *
// * TODO We will also need a method to report the JOIN_VARS if the backing
// * data structure is an HTree or BTree. [Really, what we need is a method to
// * describe how the index key will be generated, or just a method to
// * generate the key. Also, it is possible that
// * {@link ISolutionSetStats#getAlwaysBound} will report variables which are
// * always bound but which are not part of the key for the index.
// */
// public String[] getJoinVars();
}