| /* |
| * 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.IOException; |
| import org.apache.lucene.index.SegmentReadState; |
| import org.apache.lucene.index.SegmentWriteState; |
| import org.apache.lucene.index.VectorValues; |
| import org.apache.lucene.search.TopDocs; |
| import org.apache.lucene.search.TopDocsCollector; |
| import org.apache.lucene.util.NamedSPILoader; |
| |
| /** |
| * Encodes/decodes per-document vector and any associated indexing structures required to support |
| * nearest-neighbor search |
| */ |
| public abstract class VectorFormat implements NamedSPILoader.NamedSPI { |
| |
| /** |
| * This static holder class prevents classloading deadlock by delaying init of doc values formats |
| * until needed. |
| */ |
| private static final class Holder { |
| private static final NamedSPILoader<VectorFormat> LOADER = |
| new NamedSPILoader<>(VectorFormat.class); |
| |
| private Holder() {} |
| |
| static NamedSPILoader<VectorFormat> getLoader() { |
| if (LOADER == null) { |
| throw new IllegalStateException( |
| "You tried to lookup a VectorFormat name before all formats could be initialized. " |
| + "This likely happens if you call VectorFormat#forName from a VectorFormat's ctor."); |
| } |
| return LOADER; |
| } |
| } |
| |
| private final String name; |
| |
| /** Sole constructor */ |
| protected VectorFormat(String name) { |
| NamedSPILoader.checkServiceName(name); |
| this.name = name; |
| } |
| |
| @Override |
| public String getName() { |
| return name; |
| } |
| |
| /** looks up a format by name */ |
| public static VectorFormat forName(String name) { |
| return Holder.getLoader().lookup(name); |
| } |
| |
| /** Returns a {@link VectorWriter} to write the vectors to the index. */ |
| public abstract VectorWriter fieldsWriter(SegmentWriteState state) throws IOException; |
| |
| /** Returns a {@link VectorReader} to read the vectors from the index. */ |
| public abstract VectorReader fieldsReader(SegmentReadState state) throws IOException; |
| |
| /** |
| * EMPTY throws an exception when written. It acts as a sentinel indicating a Codec that does not |
| * support vectors. |
| */ |
| public static final VectorFormat EMPTY = |
| new VectorFormat("EMPTY") { |
| @Override |
| public VectorWriter fieldsWriter(SegmentWriteState state) { |
| throw new UnsupportedOperationException( |
| "Attempt to write EMPTY VectorValues: maybe you forgot to use codec=Lucene90"); |
| } |
| |
| @Override |
| public VectorReader fieldsReader(SegmentReadState state) { |
| return new VectorReader() { |
| @Override |
| public void checkIntegrity() {} |
| |
| @Override |
| public VectorValues getVectorValues(String field) { |
| return VectorValues.EMPTY; |
| } |
| |
| @Override |
| public TopDocs search(String field, float[] target, int k, int fanout) { |
| return TopDocsCollector.EMPTY_TOPDOCS; |
| } |
| |
| @Override |
| public void close() {} |
| |
| @Override |
| public long ramBytesUsed() { |
| return 0; |
| } |
| }; |
| } |
| }; |
| } |