/**
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
*/
/*
* Created on Oct 20, 2011
*/
package com.bigdata.rdf.sparql.ast;
import java.util.List;
import com.bigdata.rdf.sparql.ast.optimizers.ASTAttachJoinFiltersOptimizer;
import com.bigdata.rdf.sparql.ast.optimizers.ASTSimpleOptionalOptimizer;
/**
* A marker interface for any kind of AST Node which joins stuff.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public interface IJoinNode extends IBindingProducerNode {
public interface Annotations {
/**
* A {@link List} of {@link FilterNode}s for constraints which MUST run
* <em>with</em> the JOIN.
*/
String FILTERS = "filters";
/**
* Boolean flag indicates that a join node has OPTIONAL semantics.
*/
String OPTIONAL = "optional";
boolean DEFAULT_OPTIONAL = false;
/**
* When <code>true</code>, the join group has the semantics of a SPARQL
* MINUS operator and only those solutions in the parent group which do
* NOT join with this group will be output.
*/
String MINUS = "minus";
boolean DEFAULT_MINUS = false;
}
/**
* Return whether or not this is an join with "optional" semantics. Optional
* joins may or may not produce variable bindings, but will not reduce the
* incoming solutions based on whether or not they bind.
*/
boolean isOptional();
/**
* Return <code>true</code> iff this is a join group representing a SPARQL
* MINUS operator.
*/
boolean isMinus();
/**
* Return the FILTER(s) associated with this {@link IJoinNode}. Such filters
* will be run with the JOIN for this statement pattern. As such, they MUST
* NOT rely on materialization of variables which would not have been bound
* before that JOIN.
*
* @return The attached join filters and never <code>null</code> (it may
* return an empty list)(.
*
* @see ASTSimpleOptionalOptimizer
* @see ASTAttachJoinFiltersOptimizer
*/
List<FilterNode> getAttachedJoinFilters();
void setAttachedJoinFilters(final List<FilterNode> filters);
}