| /* |
| * 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.io.IOException; |
| |
| import org.apache.lucene.search.DocIdSetIterator; |
| import org.apache.lucene.util.BytesRef; |
| |
| /** Iterates through the postings. |
| * NOTE: you must first call {@link #nextDoc} before using |
| * any of the per-doc methods. */ |
| public abstract class PostingsEnum extends DocIdSetIterator { |
| |
| /** |
| * Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} if you don't |
| * require per-document postings in the returned enum. |
| */ |
| public static final short NONE = 0; |
| |
| /** Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} |
| * if you require term frequencies in the returned enum. */ |
| public static final short FREQS = 1 << 3; |
| |
| /** Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} |
| * if you require term positions in the returned enum. */ |
| public static final short POSITIONS = FREQS | 1 << 4; |
| |
| /** Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} |
| * if you require offsets in the returned enum. */ |
| public static final short OFFSETS = POSITIONS | 1 << 5; |
| |
| /** Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} |
| * if you require payloads in the returned enum. */ |
| public static final short PAYLOADS = POSITIONS | 1 << 6; |
| |
| /** |
| * Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} |
| * to get positions, payloads and offsets in the returned enum |
| */ |
| public static final short ALL = OFFSETS | PAYLOADS; |
| |
| /** |
| * Returns true if the given feature is requested in the flags, false otherwise. |
| */ |
| public static boolean featureRequested(int flags, short feature) { |
| return (flags & feature) == feature; |
| } |
| |
| /** Sole constructor. (For invocation by subclass |
| * constructors, typically implicit.) */ |
| protected PostingsEnum() { |
| } |
| |
| /** |
| * Returns term frequency in the current document, or 1 if the field was |
| * indexed with {@link IndexOptions#DOCS}. Do not call this before |
| * {@link #nextDoc} is first called, nor after {@link #nextDoc} returns |
| * {@link DocIdSetIterator#NO_MORE_DOCS}. |
| * |
| * <p> |
| * <b>NOTE:</b> if the {@link PostingsEnum} was obtain with {@link #NONE}, |
| * the result of this method is undefined. |
| */ |
| public abstract int freq() throws IOException; |
| |
| /** |
| * Returns the next position, or -1 if positions were not indexed. |
| * Calling this more than {@link #freq()} times is undefined. |
| */ |
| public abstract int nextPosition() throws IOException; |
| |
| /** Returns start offset for the current position, or -1 |
| * if offsets were not indexed. */ |
| public abstract int startOffset() throws IOException; |
| |
| /** Returns end offset for the current position, or -1 if |
| * offsets were not indexed. */ |
| public abstract int endOffset() throws IOException; |
| |
| /** Returns the payload at this position, or null if no |
| * payload was indexed. You should not modify anything |
| * (neither members of the returned BytesRef nor bytes |
| * in the byte[]). */ |
| public abstract BytesRef getPayload() throws IOException; |
| |
| } |