InferenceBVE.java

package com.bigdata.rdf.internal.constraints;

import java.util.Map;

import com.bigdata.bop.BOp;
import com.bigdata.bop.BOpBase;
import com.bigdata.bop.IBindingSet;
import com.bigdata.bop.constraint.BooleanValueExpression;
import com.bigdata.rdf.error.SparqlTypeErrorException;
import com.bigdata.rdf.internal.impl.literal.XSDBooleanIV;

public class InferenceBVE extends BOpBase implements BooleanValueExpression {

    /**
	 * 
	 */
	private static final long serialVersionUID = -5713570348190136135L;

	public InferenceBVE(final XSDBooleanIVValueExpression x) {
		
        this(new BOp[] { x }, null/*annocations*/);
        
    }
    
    /**
     * Required shallow copy constructor.
     */
    public InferenceBVE(final BOp[] args, final Map<String, Object> anns) {

    	super(args, anns);
    	
        if (args.length != 1 || args[0] == null)
            throw new IllegalArgumentException();
        
    }

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

    /**
     * For inference rules, we want to trap unbound variable exceptions and
     * allow the solution through.
     */
    public Boolean get(final IBindingSet bs) {

    	final XSDBooleanIVValueExpression bop = 
    		(XSDBooleanIVValueExpression) get(0);

    	try {
    		final XSDBooleanIV iv = bop.get(bs);
    		return iv.booleanValue();
    	} catch (SparqlTypeErrorException ex) {
    		// allow unbound variables
    		return true;
    	}
    	
    }
	
}