| package org.apache.lucene.codecs; |
| |
| /* |
| * 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. |
| */ |
| |
| import java.io.IOException; |
| import java.io.Closeable; |
| |
| import org.apache.lucene.index.DocsEnum; |
| import org.apache.lucene.index.DocsAndPositionsEnum; |
| import org.apache.lucene.index.FieldInfo; |
| import org.apache.lucene.store.IndexInput; |
| import org.apache.lucene.util.Bits; |
| |
| /** The core terms dictionaries (BlockTermsReader, |
| * BlockTreeTermsReader) interact with a single instance |
| * of this class to manage creation of {@link DocsEnum} and |
| * {@link DocsAndPositionsEnum} 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: 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 { |
| |
| /** 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) throws IOException; |
| |
| /** Return a newly created empty TermState */ |
| public abstract BlockTermState newTermState() throws IOException; |
| |
| /** Actually decode metadata for next term */ |
| public abstract void nextTerm(FieldInfo fieldInfo, BlockTermState state) throws IOException; |
| |
| /** Must fully consume state, since after this call that |
| * TermState may be reused. */ |
| public abstract DocsEnum docs(FieldInfo fieldInfo, BlockTermState state, Bits skipDocs, DocsEnum reuse, int flags) throws IOException; |
| |
| /** Must fully consume state, since after this call that |
| * TermState may be reused. */ |
| public abstract DocsAndPositionsEnum docsAndPositions(FieldInfo fieldInfo, BlockTermState state, Bits skipDocs, DocsAndPositionsEnum reuse, |
| int flags) throws IOException; |
| |
| @Override |
| public abstract void close() throws IOException; |
| |
| /** Reads data for all terms in the next block; this |
| * method should merely load the byte[] blob but not |
| * decode, which is done in {@link #nextTerm}. */ |
| public abstract void readTermsBlock(IndexInput termsIn, FieldInfo fieldInfo, BlockTermState termState) throws IOException; |
| } |