/**
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
*/
package com.bigdata.rdf.internal.constraints;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import com.bigdata.bop.BOp;
import com.bigdata.bop.IBindingSet;
import com.bigdata.bop.IConstant;
import com.bigdata.bop.IValueExpression;
import com.bigdata.rdf.error.SparqlTypeErrorException;
import com.bigdata.rdf.internal.IV;
import com.bigdata.rdf.sparql.ast.GlobalAnnotations;
/**
* A constraint that a value expression which may only take on the bindings
* enumerated by some set of constants.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id: INHashMap.java 4357 2011-03-31 17:11:26Z thompsonbry $
*/
public class InHashBOp extends InBOp {
/**
*
*/
private static final long serialVersionUID = 8032412126003678642L;
/**
* The value expression to be computed for each solution (cached).
* <p>
* Note: This cache is not serialized and is compiled on demand when the
* operator is used.
*/
private transient volatile IValueExpression<IV> valueExpr;
/**
* The set of constants to be tested (cached).
* <p>
* Note: This cache is not serialized and is compiled on demand when the
* operator is used.
*/
private transient volatile LinkedHashSet<IV> set;
/**
* <code>true</code> iff this is NOT IN (cached).
* <p>
* Note: This cache is not serialized and is compiled on demand when the
* operator is used.
*/
private transient boolean not;
/**
* Deep copy constructor.
*/
public InHashBOp(final InHashBOp op) {
super(op);
}
/**
* Shallow copy constructor.
*/
public InHashBOp(final BOp[] args, final Map<String, Object> annotations) {
super(args, annotations);
}
/**
*
* @param x
* Some variable.
* @param set
* A set of legal term identifiers providing a constraint on the
* allowable values for that variable.
*/
@SuppressWarnings("rawtypes")
public InHashBOp(
final boolean not, //
final IValueExpression<? extends IV> var,
final IConstant<? extends IV>... set) {
super(not, var, set);
}
/**
* Extends {@link com.bigdata.bop.CoreBaseBOp#mutation() CoreBaseBOp.mutation} method to reflect args changes in cached IVs set.
*/
@Override
public void mutation() {
super.mutation();
if (set != null) {
synchronized (this) {
if (set != null) {
// clearing cached set is guarded by double-checked locking pattern.
set = null;
}
}
}
}
private void init() {
valueExpr = getValueExpression();
// populate the cache.
final IConstant<IV>[] a = getSet();
set = new LinkedHashSet<IV>(a.length);
for (IConstant<IV> IV : a) {
final IV val = IV.get();
set.add(val);
}
not = ((Boolean) getProperty(Annotations.NOT)).booleanValue();
}
public boolean accept(final IBindingSet bindingSet) {
final Set<IV> _set;
if (valueExpr == null||set==null) {
synchronized (this) {
if (valueExpr == null||set==null) {
// init() is guarded by double-checked locking pattern.
init();
}
// "set" is pulled into a local variable in this double-checked locking pattern
// to avoid the possibility that set is resolved to non-null
// and then cleared to null before it is used in accept()
_set = set;
}
} else {
_set = set;
}
// get as-bound value of the value expression.
final IV v = valueExpr.get(bindingSet);
if (v == null)
throw new SparqlTypeErrorException.UnboundVarException();
final boolean found = _set.contains(v);
return not ? !found : found;
}
}