| /* |
| * 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.lucene.expressions; |
| |
| import java.io.IOException; |
| |
| import org.apache.lucene.search.DoubleValues; |
| |
| /** A {@link DoubleValues} which evaluates an expression */ |
| class ExpressionFunctionValues extends DoubleValues { |
| final Expression expression; |
| final DoubleValues[] functionValues; |
| double currentValue; |
| int currentDoc = -1; |
| boolean computed; |
| |
| ExpressionFunctionValues(Expression expression, DoubleValues[] functionValues) { |
| if (expression == null) { |
| throw new NullPointerException(); |
| } |
| if (functionValues == null) { |
| throw new NullPointerException(); |
| } |
| this.expression = expression; |
| this.functionValues = functionValues; |
| } |
| |
| @Override |
| public boolean advanceExact(int doc) throws IOException { |
| if (currentDoc == doc) { |
| return true; |
| } |
| for (DoubleValues v : functionValues) { |
| v.advanceExact(doc); |
| } |
| currentDoc = doc; |
| computed = false; |
| return true; |
| } |
| |
| @Override |
| public double doubleValue() { |
| if (computed == false) { |
| currentValue = expression.evaluate(functionValues); |
| computed = true; |
| } |
| return currentValue; |
| } |
| } |