| /* |
| * 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.codecs; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import org.apache.lucene.index.FieldInfo; |
| import org.apache.lucene.index.ImpactsEnum; |
| import org.apache.lucene.index.PostingsEnum; |
| import org.apache.lucene.index.SegmentReadState; |
| import org.apache.lucene.store.DataInput; |
| import org.apache.lucene.store.IndexInput; |
| import org.apache.lucene.util.Accountable; |
| |
| /** |
| * The core terms dictionaries (BlockTermsReader, BlockTreeTermsReader) interact with a single |
| * instance of this class to manage creation of {@link org.apache.lucene.index.PostingsEnum} and |
| * {@link org.apache.lucene.index.PostingsEnum} instances. It provides an IndexInput (termsIn) where |
| * this class may read any previously stored data that it had written in its corresponding {@link |
| * PostingsWriterBase} at indexing time. |
| * |
| * @lucene.experimental |
| */ |
| |
| // TODO: maybe move under blocktree? but it's used by other terms dicts (e.g. Block) |
| |
| // TODO: find a better name; this defines the API that the |
| // terms dict impls use to talk to a postings impl. |
| // TermsDict + PostingsReader/WriterBase == PostingsConsumer/Producer |
| public abstract class PostingsReaderBase implements Closeable, Accountable { |
| |
| /** Sole constructor. (For invocation by subclass constructors, typically implicit.) */ |
| protected PostingsReaderBase() {} |
| |
| /** |
| * Performs any initialization, such as reading and verifying the header from the provided terms |
| * dictionary {@link IndexInput}. |
| */ |
| public abstract void init(IndexInput termsIn, SegmentReadState state) throws IOException; |
| |
| /** Return a newly created empty TermState */ |
| public abstract BlockTermState newTermState() throws IOException; |
| |
| /** |
| * Actually decode metadata for next term |
| * |
| * @see PostingsWriterBase#encodeTerm |
| */ |
| public abstract void decodeTerm( |
| DataInput in, FieldInfo fieldInfo, BlockTermState state, boolean absolute) throws IOException; |
| |
| /** Must fully consume state, since after this call that TermState may be reused. */ |
| public abstract PostingsEnum postings( |
| FieldInfo fieldInfo, BlockTermState state, PostingsEnum reuse, int flags) throws IOException; |
| |
| /** |
| * Return a {@link ImpactsEnum} that computes impacts with {@code scorer}. |
| * |
| * @see #postings(FieldInfo, BlockTermState, PostingsEnum, int) |
| */ |
| public abstract ImpactsEnum impacts(FieldInfo fieldInfo, BlockTermState state, int flags) |
| throws IOException; |
| |
| /** |
| * Checks consistency of this reader. |
| * |
| * <p>Note that this may be costly in terms of I/O, e.g. may involve computing a checksum value |
| * against large data files. |
| * |
| * @lucene.internal |
| */ |
| public abstract void checkIntegrity() throws IOException; |
| |
| @Override |
| public abstract void close() throws IOException; |
| } |