SparqlSubstitute.java

package org.aksw.jena_sparql_api.views;

import java.util.Arrays;

import org.aksw.commons.util.reflect.MultiMethod;
import org.apache.jena.sparql.expr.E_Function;
import org.apache.jena.sparql.expr.Expr;
import org.apache.jena.sparql.expr.ExprList;
import org.apache.jena.sparql.expr.NodeValue;

/**
 * Macro Expansion, e.g. beef:uri - beef:term()
 *
 * @author raven
 *
 */
public class SparqlSubstitute {
    public static Expr substituteExpr(Expr expr) {
        return (Expr) MultiMethod.invokeStatic(SparqlSubstitute.class,
                "substitute", expr);
    }

    public static Expr substitute(Expr expr) {
        return expr;
    }

    @SuppressWarnings("unchecked")
    public static ExprList makeExprList(Expr... exprs) {
        return new ExprList(Arrays.asList(exprs));
    }

    public static Expr substitute(E_Function expr) {

        if(expr.getFunctionIRI().equals(SparqlifyConstants.rdfTermLabel)) {
            if(expr.getArgs().size() != 4) {
                throw new RuntimeException("RdfTerm requires 4 arguments, instead got: " + expr);
            }

            return new E_RdfTerm(
                    expr.getArg(1), expr.getArg(2), expr.getArg(3), expr.getArg(4));
        } else if (expr.getFunctionIRI().equals(SparqlifyConstants.uriLabel)) {
            return new E_RdfTerm(
                    NodeValue.makeDecimal(1), expr.getArgs().get(0),
                    NodeValue.makeString(""), NodeValue.makeString(""));
        } else if (expr.getFunctionIRI()
                .equals(SparqlifyConstants.plainLiteralLabel)) {
            // The second argument is optional
            // If it is null, "", or not present, it will be treated as ""
            Expr lang = NodeValue.makeString("");

            if (expr.getArgs().size() == 2) {
                Expr tmp = expr.getArgs().get(1);
                if (tmp != null) {
                    lang = tmp;
                }
            }

            return new E_RdfTerm(
                    NodeValue.makeDecimal(2), expr.getArgs().get(0), lang,
                    NodeValue.makeString(""));
        } else if (expr.getFunctionIRI()
                .equals(SparqlifyConstants.typedLiteralLabel)) {
            return new E_RdfTerm(
                    NodeValue.makeDecimal(3), expr.getArgs().get(0),
                    NodeValue.makeString(""), expr.getArgs().get(1));
        } else if (expr.getFunctionIRI().equals(SparqlifyConstants.blankNodeLabel)) {
            return new E_RdfTerm(
                    NodeValue.makeDecimal(0), expr.getArgs().get(0),
                    NodeValue.makeString(""), NodeValue.makeString(""));
        }

        return expr;
    }
    /*
    public static Expr substitute(E_Function expr) {
        if (expr.getFunctionIRI().equals(SparqlifyConstants.uriLabel)) {
            return new E_Function(SparqlifyConstants.rdfTermLabel, makeExprList(
                    NodeValue.makeDecimal(1), expr.getArgs().get(0),
                    NodeValue.makeString(""), NodeValue.makeString("")));
        } else if (expr.getFunctionIRI()
                .equals(SparqlifyConstants.plainLiteralLabel)) {
            // The second argument is optional
            // If it is null, "", or not present, it will be treated as ""
            Expr lang = NodeValue.makeString("");

            if (expr.getArgs().size() == 2) {
                Expr tmp = expr.getArgs().get(1);
                if (tmp != null) {
                    lang = tmp;
                }
            }

            return new E_Function(SparqlifyConstants.rdfTermLabel, makeExprList(
                    NodeValue.makeDecimal(2), expr.getArgs().get(0), lang,
                    NodeValue.makeString("")));
        } else if (expr.getFunctionIRI()
                .equals(SparqlifyConstants.typedLiteralLabel)) {
            return new E_Function(SparqlifyConstants.rdfTermLabel, makeExprList(
                    NodeValue.makeDecimal(3), expr.getArgs().get(0),
                    NodeValue.makeString(""), expr.getArgs().get(1)));
        }

        return expr;
    }*/
}