/*
* 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 com.hp.hpl.jena.sparql.function.user;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.hp.hpl.jena.sparql.core.Var;
import com.hp.hpl.jena.sparql.expr.Expr;
import com.hp.hpl.jena.sparql.function.Function;
import com.hp.hpl.jena.sparql.sse.builders.ExprBuildException;
/**
* Represents the definition of a user defined function
*
*/
public class UserDefinedFunctionDefinition {
private static final Logger LOG = LoggerFactory.getLogger(UserDefinedFunctionDefinition.class);
/**
* Whether to log warnings for unused variables
*/
public static boolean warnOnUnusedVariable = true;
private String uri;
private Expr expr;
private List<Var> argList;
/**
* Creates a user defined function definition
* @param uri Function URL
* @param e Expression
* @param argList Arguments
*/
public UserDefinedFunctionDefinition(String uri, Expr e, List<Var> argList) {
this.uri = uri;
this.expr = e;
this.argList = new ArrayList<Var>(argList);
//Verify that all mentioned variables are in the arguments list
Set<Var> mentioned = this.expr.getVarsMentioned();
for (Var v : mentioned) {
if (!argList.contains(v)) throw new ExprBuildException("Cannot use the variable " + v.toString() + " in the expression since it is not included in the argList argument. All variables must be arguments to the function");
}
//If used variables is greater than argument variables this is an error
if (mentioned.size() > this.argList.size()) throw new ExprBuildException("Mismatch between variables used in expression and number of variables in argument list, expected " + this.argList.size() + " but found " + mentioned.size());
//May have more arguments than used, however this only gives warning(s)
if (mentioned.size() < this.argList.size()) {
for (Var v : this.argList) {
if (!mentioned.contains(v) && warnOnUnusedVariable) LOG.warn("Function <" + uri + "> has argument " + v + " which is never used in the expression");
}
}
}
/**
* Gets the base expression
* @return Expression
*/
public Expr getBaseExpr() {
return this.expr;
}
/**
* Gets the argument list
* @return Arguments
*/
public List<Var> getArgList() {
return this.argList;
}
/**
* Gets the function URI
* @return URI
*/
public String getUri() {
return this.uri;
}
/**
* Gets an instance of an actual {@link Function} that can be used to evaluate this function
* @return Function instance
*/
public Function newFunctionInstance() {
return new UserDefinedFunction(this);
}
}