/*
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.Map;
import com.bigdata.bop.BOp;
import com.bigdata.bop.IBindingSet;
import com.bigdata.bop.IValueExpression;
import com.bigdata.bop.NV;
import com.bigdata.rdf.error.SparqlTypeErrorException;
import com.bigdata.rdf.internal.IV;
import com.bigdata.rdf.internal.impl.literal.XSDBooleanIV;
import com.bigdata.rdf.sparql.ast.GlobalAnnotations;
/**
* Imposes the constraint <code>x AND y</code>. Each operand of this operator
* must evaluate to a boolean. If the operand is not known to evaluate to a
* boolean, it is wrapped with an {@link EBVBOp}.
*/
public class AndBOp extends XSDBooleanIVValueExpression {
/**
*
*/
private static final long serialVersionUID = -1217715173822304819L;
public AndBOp(
final IValueExpression<? extends IV> x,
final IValueExpression<? extends IV> y) {
this(new BOp[] { wrap(x), wrap(y) }, BOp.NOANNS);
}
/**
* Required shallow copy constructor.
*/
public AndBOp(final BOp[] args, final Map<String, Object> anns) {
super(args, anns);
if (args.length != 2 || args[0] == null || args[1] == null)
throw new IllegalArgumentException();
if (!(args[0] instanceof XSDBooleanIVValueExpression))
throw new IllegalArgumentException();
if (!(args[1] instanceof XSDBooleanIVValueExpression))
throw new IllegalArgumentException();
}
/**
* Constructor required for {@link com.bigdata.bop.BOpUtility#deepCopy(FilterNode)}.
*/
public AndBOp(final AndBOp op) {
super(op);
}
@Override
public XSDBooleanIVValueExpression get(final int i) {
return (XSDBooleanIVValueExpression) super.get(i);
}
/**
* Follows semantics from SPARQL spec - "Testing Values".
* <p>
* see http://www.w3.org/TR/rdf-sparql-query/#tests section 11.2
*/
public boolean accept(final IBindingSet bs) {
XSDBooleanIV left, right;
try {
left = get(0).get(bs);
} catch (SparqlTypeErrorException ex) {
left = null;
}
try {
right = get(1).get(bs);
} catch (SparqlTypeErrorException ex) {
right = null;
}
// special error handling per the SPARQL spec
if (left == null || right == null) {
// if one or the other is false, return false
if (left != null && !left.booleanValue())
return false;
if (right != null && !right.booleanValue())
return false;
// all other cases, throw a type error
throw new SparqlTypeErrorException();
}
return left.booleanValue() && right.booleanValue();
}
}