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ARQ is a SPARQL 1.1 query engine for Apache Jena

There is a newer version: 5.1.0

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.sparql.function.library;

import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.expr.E_Call ;
import org.apache.jena.sparql.expr.ExprList ;
import org.apache.jena.sparql.expr.NodeValue ;
import org.apache.jena.sparql.function.Function ;
import org.apache.jena.sparql.function.FunctionEnv ;

/** Function that evaluates an expression.
 *  To convert errors to true or false, use COALESCE. 
 */

public class eval implements Function
{
    @Override
    public void build(String uri, ExprList args) {}

    /** Processes unevaluated arguments */
    
    @Override
    public NodeValue exec(Binding binding, ExprList args, String uri, FunctionEnv env)
    {
        E_Call e = new E_Call(args) ;
        NodeValue nv = e.evalSpecial(binding, env) ;
        if ( nv != null )
            return nv ;
        return e.eval(binding, env) ;
    }  
}