LiteralLanguageTestEvaluator.java

package com.github.anno4j.querying.evaluation.ldpath;

import com.github.anno4j.querying.evaluation.LDPathEvaluatorConfiguration;
import com.github.anno4j.querying.extension.TestEvaluator;
import com.github.anno4j.annotations.Evaluator;
import com.hp.hpl.jena.sparql.core.Var;
import com.hp.hpl.jena.sparql.expr.E_Lang;
import com.hp.hpl.jena.sparql.expr.E_LangMatches;
import com.hp.hpl.jena.sparql.expr.Expr;
import com.hp.hpl.jena.sparql.expr.ExprVar;
import com.hp.hpl.jena.sparql.expr.nodevalue.NodeValueString;
import com.hp.hpl.jena.sparql.syntax.ElementFilter;
import com.hp.hpl.jena.sparql.syntax.ElementGroup;
import org.apache.marmotta.ldpath.api.selectors.NodeSelector;
import org.apache.marmotta.ldpath.api.tests.NodeTest;
import org.apache.marmotta.ldpath.model.selectors.TestingSelector;
import org.apache.marmotta.ldpath.model.tests.LiteralLanguageTest;

/**
 * Creates the part of the SPARQL query that tests for a specific language.
 */
@Evaluator(LiteralLanguageTest.class)
public class LiteralLanguageTestEvaluator implements TestEvaluator {
    @Override
    public Var evaluate(NodeSelector nodeSelector, ElementGroup elementGroup, Var var, LDPathEvaluatorConfiguration evaluatorConfiguration) {
        TestingSelector testingSelector = (TestingSelector) nodeSelector;
        NodeTest nodeTest = testingSelector.getTest();
        Var delVar = LDPathEvaluator.evaluate(testingSelector.getDelegate(), elementGroup, var, evaluatorConfiguration);

        elementGroup.addElementFilter(new ElementFilter(evaluate(nodeTest, elementGroup, delVar, evaluatorConfiguration)));
        return delVar;
    }

    @Override
    public Expr evaluate(NodeTest nodeTest, ElementGroup elementGroup, Var var, LDPathEvaluatorConfiguration evaluatorConfiguration) {
        LiteralLanguageTest literalLanguageTest = (LiteralLanguageTest) nodeTest;
        return new E_LangMatches(new E_Lang(new ExprVar(var)), new NodeValueString(literalLanguageTest.getLang()));
    }
}