/**
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 Aug 18, 2011
*/
package com.bigdata.rdf.sparql.ast;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import com.bigdata.bop.BOp;
import com.bigdata.bop.IVariable;
import com.bigdata.rdf.sparql.ast.eval.IEvaluationContext;
/**
* An AST node which provides a reference in an {@link IGroupNode} and indicates
* that a named solution set should be joined with the solutions in the group.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*
* @see NamedSubqueryRoot
*/
public class NamedSubqueryInclude extends
GroupMemberNodeBase<NamedSubqueryInclude> implements
IJoinNode, INamedSolutionSet {
private static final long serialVersionUID = 1L;
public interface Annotations extends IJoinNode.Annotations,
INamedSolutionSet.Annotations {
/**
* A {@link VarNode}[] specifying the join variables that will be used
* when the named result set is join with the query. The join variables
* MUST be bound for a solution to join.
* <p>
* Note: This can be different for each context in the query in which a
* given named result set is included. When there are different join
* variables for different INCLUDEs, then we need to build a hash index
* for each set of join variable context that will be consumed within
* the query.
* <p>
* Note: If no join variables are specified, then the join will consider
* the N x M cross product, filtering for solutions which join. This is
* very expensive. Whenever possible you should identify one or more
* variables which must be bound for the join and specify those as the
* join variables.
*/
String JOIN_VARS = "joinVars";
/*
* Note: This is an unfinished concept in support of
* "Optimize hash joins when there are no source solutions (or only the exogenous bindings)"
* .
*
* @see https://sourceforge.net/apps/trac/bigdata/ticket/405
*/
// /**
// * When <code>true</code>, the join variables will be ignored when
// * performing the join. This option makes it possible to build an index
// * using join variables, but to evaluate the join without regard to
// * those join variables.
// * <p>
// * The most common use case is used when an INCLUDE appears as the first
// * {@link IJoinNode} in a query. In this case, the only left solution is
// * the exogenous solution which, by default, does not have any bindings.
// * By using a naive join we can scan a hash index built using one or
// * more join variables, testing each solution in turn against the
// * exogenous solution. This is efficient since it uses a single pass
// * over the hash index and correct since it ignores the join variables
// * for the left solution.
// */
// String NAIVE_JOIN = "naiveJoin";
//
// boolean DEFAULT_NAIVE_JOIN = false;
}
/**
* Constructor required for {@link com.bigdata.bop.BOpUtility#deepCopy(FilterNode)}.
*/
public NamedSubqueryInclude(final NamedSubqueryInclude op) {
super(op);
}
/**
* Required shallow copy constructor.
*/
public NamedSubqueryInclude(final BOp[] args, final Map<String, Object> anns) {
super(args, anns);
}
/**
* @param name
* The name of the subquery result set.
*/
public NamedSubqueryInclude(final String name) {
setName(name);
}
@Override
public String getName() {
return (String) getProperty(Annotations.NAMED_SET);
}
@Override
public void setName(final String name) {
if (name == null)
throw new IllegalArgumentException();
setProperty(Annotations.NAMED_SET, name);
}
/**
* The join variables to be used when the named result set is included into
* the query.
*/
public VarNode[] getJoinVars() {
return (VarNode[]) getProperty(Annotations.JOIN_VARS);
}
/**
* Set the join variables.
*
* @param joinVars
* The join variables.
*/
public void setJoinVars(final VarNode[] joinVars) {
setProperty(Annotations.JOIN_VARS, joinVars);
}
/**
* Return the ordered set of join variables.
*
* @return The ordered set of join variables and never <code>null</code>.
*/
@SuppressWarnings("rawtypes")
public Set<IVariable<?>> getJoinVarSet() {
final Set<IVariable<?>> set = new LinkedHashSet<IVariable<?>>();
final VarNode[] a = getJoinVars();
if (a != null && a.length > 0) {
for (IVariable v : ASTUtil.convert(a)) {
set.add(v);
}
}
return set;
}
/**
* Returns <code>false</code>.
*/
@Override
final public boolean isOptional() {
return false;
}
/**
* Returns <code>false</code>.
*/
@Override
final public boolean isMinus() {
return false;
}
@Override
final public List<FilterNode> getAttachedJoinFilters() {
@SuppressWarnings("unchecked")
final List<FilterNode> filters = (List<FilterNode>) getProperty(Annotations.FILTERS);
if (filters == null) {
return Collections.emptyList();
}
return Collections.unmodifiableList(filters);
}
@Override
final public void setAttachedJoinFilters(final List<FilterNode> filters) {
setProperty(Annotations.FILTERS, filters);
}
@Override
public String toString(int indent) {
final StringBuilder sb = new StringBuilder();
sb.append("\n");
sb.append(indent(indent));
sb.append("INCLUDE ").append(getName());
final VarNode[] joinVars = getJoinVars();
if (joinVars != null) {
sb.append(" JOIN ON (");
boolean first = true;
for (VarNode var : joinVars) {
if (!first)
sb.append(",");
sb.append(var);
first = false;
}
sb.append(")");
}
// if (getProperty(Annotations.NAIVE_JOIN, Annotations.DEFAULT_NAIVE_JOIN)) {
//
// sb.append(" [naiveJoin]");
//
// }
final List<FilterNode> filters = getAttachedJoinFilters();
if(!filters.isEmpty()) {
for (FilterNode filter : filters) {
sb.append(filter.toString(indent + 1));
}
}
return sb.toString();
}
@Override
public Set<IVariable<?>> getRequiredBound(StaticAnalysis sa) {
final NamedSubqueryRoot nsr = sa.resolveNamedSubqueryInclude(this, sa);
return nsr==null ?
new HashSet<IVariable<?>>() : nsr.getRequiredBound(sa);
}
@Override
public Set<IVariable<?>> getDesiredBound(StaticAnalysis sa) {
final NamedSubqueryRoot nsr = sa.resolveNamedSubqueryInclude(this, sa);
return nsr==null ?
new HashSet<IVariable<?>>() : nsr.getDesiredBound(sa);
}
}