/*
* 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;
import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.expr.ExprList ;
import org.apache.jena.sparql.expr.NodeValue ;
/** Interface to value-testing extensions to the expression evaluator. */
public interface Function
{
/** Called during query plan construction immediately after the
* construction of the extension instance.
* Can throw ExprBuildException if something is wrong (like wrong number of arguments).
* @param args The parsed arguments
*/
public void build(String uri, ExprList args) ;
/** Test a list of values - argument will not be null but
* may have the wrong number of arguments.
* FunctionBase provides a more convenient way to implement a function.
* Can throw ExprEvalsException if something goes wrong.
*
* @param binding The current solution
* @param args A list of unevaluated expressions
* @param uri The name of this
* @param env The execution context
* @return NodeValue - a value
*/
public NodeValue exec(Binding binding, ExprList args, String uri, FunctionEnv env) ;
}