package org.apache.lucene.expressions;
/*
* 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.
*/
import org.apache.lucene.queries.function.FunctionValues;
import org.apache.lucene.queries.function.ValueSource;
import org.apache.lucene.queries.function.docvalues.DoubleDocValues;
/** A {@link FunctionValues} which evaluates an expression */
class ExpressionFunctionValues extends DoubleDocValues {
final Expression expression;
final FunctionValues[] functionValues;
int currentDocument = -1;
double currentValue;
ExpressionFunctionValues(ValueSource parent, Expression expression, FunctionValues[] functionValues) {
super(parent);
if (expression == null) {
throw new NullPointerException();
}
if (functionValues == null) {
throw new NullPointerException();
}
this.expression = expression;
this.functionValues = functionValues;
}
@Override
public double doubleVal(int document) {
if (currentDocument != document) {
currentDocument = document;
currentValue = expression.evaluate(document, functionValues);
}
return currentValue;
}
}