| /* |
| * 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.index; |
| |
| import java.util.List; |
| |
| /** |
| * Information about upcoming impacts, ie. (freq, norm) pairs. |
| */ |
| public abstract class Impacts { |
| |
| /** Sole constructor. Typically invoked by sub classes. */ |
| protected Impacts() {} |
| |
| /** |
| * Return the number of levels on which we have impacts. |
| * The returned value is always greater than 0 and may not always be the |
| * same, even on a single postings list, depending on the current doc ID. |
| */ |
| public abstract int numLevels(); |
| |
| /** |
| * Return the maximum inclusive doc ID until which the list of impacts |
| * returned by {@link #getImpacts(int)} is valid. This is a non-decreasing |
| * function of {@code level}. |
| */ |
| public abstract int getDocIdUpTo(int level); |
| |
| /** |
| * Return impacts on the given level. These impacts are sorted by increasing |
| * frequency and increasing unsigned norm, and only valid until the doc ID |
| * returned by {@link #getDocIdUpTo(int)} for the same level, included. |
| * The returned list is never empty. |
| * NOTE: There is no guarantee that these impacts actually appear in postings, |
| * only that they trigger scores that are greater than or equal to the impacts |
| * that actually appear in postings. |
| */ |
| public abstract List<Impact> getImpacts(int level); |
| |
| } |