| /* |
| * 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.search; |
| |
| import java.io.IOException; |
| |
| /** |
| * Per-segment, per-document double values, which can be calculated at search-time |
| */ |
| public abstract class DoubleValues { |
| |
| /** |
| * Get the double value for the current document |
| */ |
| public abstract double doubleValue() throws IOException; |
| |
| /** |
| * Advance this instance to the given document id |
| * @return true if there is a value for this document |
| */ |
| public abstract boolean advanceExact(int doc) throws IOException; |
| |
| /** |
| * Wrap a DoubleValues instance, returning a default if the wrapped instance has no value |
| */ |
| public static DoubleValues withDefault(DoubleValues in, double missingValue) { |
| return new DoubleValues() { |
| |
| boolean hasValue = false; |
| |
| @Override |
| public double doubleValue() throws IOException { |
| return hasValue ? in.doubleValue() : missingValue; |
| } |
| |
| @Override |
| public boolean advanceExact(int doc) throws IOException { |
| hasValue = in.advanceExact(doc); |
| return true; |
| } |
| }; |
| } |
| |
| /** |
| * An empty DoubleValues instance that always returns {@code false} from {@link #advanceExact(int)} |
| */ |
| public static final DoubleValues EMPTY = new DoubleValues() { |
| @Override |
| public double doubleValue() throws IOException { |
| throw new UnsupportedOperationException(); |
| } |
| |
| @Override |
| public boolean advanceExact(int doc) throws IOException { |
| return false; |
| } |
| }; |
| |
| } |