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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

*/
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 !x. The 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 NotBOp extends XSDBooleanIVValueExpression {

	/**
	 * 
	 */
	private static final long serialVersionUID = -5701967329003122236L;

	public NotBOp(final IValueExpression x) {

        this(new BOp[] { wrap(x) }, BOp.NOANNS);

    }

    /**
     * Required shallow copy constructor.
     */
    public NotBOp(final BOp[] args, final Map anns) {
    	
        super(args, anns);
        
        if (args.length != 1 || args[0] == null)
            throw new IllegalArgumentException();

        if (!(args[0] instanceof XSDBooleanIVValueExpression))
			throw new IllegalArgumentException();

    }

    /**
     * Constructor required for {@link com.bigdata.bop.BOpUtility#deepCopy(FilterNode)}.
     */
    public NotBOp(final NotBOp op) {
        super(op);
    }

    public boolean accept(final IBindingSet bs) {

    	final XSDBooleanIV iv = (XSDBooleanIV) get(0).get(bs);
    	
        // not yet bound
        if (iv == null)
        	throw new SparqlTypeErrorException();
    	
        return !iv.booleanValue();

    }
    
}