| /* |
| * 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 java.util.ArrayList; |
| import java.util.List; |
| import org.apache.lucene.index.Fields; |
| import org.apache.lucene.index.MappedMultiFields; |
| import org.apache.lucene.index.MergeState; |
| import org.apache.lucene.index.MultiFields; |
| import org.apache.lucene.index.ReaderSlice; |
| |
| /** |
| * Abstract API that consumes terms, doc, freq, prox, offset and payloads postings. Concrete |
| * implementations of this actually do "something" with the postings (write it into the index in a |
| * specific format). |
| * |
| * @lucene.experimental |
| */ |
| public abstract class FieldsConsumer implements Closeable { |
| |
| /** Sole constructor. (For invocation by subclass constructors, typically implicit.) */ |
| protected FieldsConsumer() {} |
| |
| // TODO: can we somehow compute stats for you...? |
| |
| // TODO: maybe we should factor out "limited" (only |
| // iterables, no counts/stats) base classes from |
| // Fields/Terms/Docs/AndPositions? |
| |
| /** |
| * Write all fields, terms and postings. This the "pull" API, allowing you to iterate more than |
| * once over the postings, somewhat analogous to using a DOM API to traverse an XML tree. |
| * |
| * <p><b>Notes</b>: |
| * |
| * <ul> |
| * <li>You must compute index statistics, including each Term's docFreq and totalTermFreq, as |
| * well as the summary sumTotalTermFreq, sumTotalDocFreq and docCount. |
| * <li>You must skip terms that have no docs and fields that have no terms, even though the |
| * provided Fields API will expose them; this typically requires lazily writing the field or |
| * term until you've actually seen the first term or document. |
| * <li>The provided Fields instance is limited: you cannot call any methods that return |
| * statistics/counts; you cannot pass a non-null live docs when pulling docs/positions |
| * enums. |
| * </ul> |
| */ |
| public abstract void write(Fields fields, NormsProducer norms) throws IOException; |
| |
| /** |
| * Merges in the fields from the readers in <code>mergeState</code>. The default implementation |
| * skips and maps around deleted documents, and calls {@link #write(Fields,NormsProducer)}. |
| * Implementations can override this method for more sophisticated merging (bulk-byte copying, |
| * etc). |
| */ |
| public void merge(MergeState mergeState, NormsProducer norms) throws IOException { |
| final List<Fields> fields = new ArrayList<>(); |
| final List<ReaderSlice> slices = new ArrayList<>(); |
| |
| int docBase = 0; |
| |
| for (int readerIndex = 0; readerIndex < mergeState.fieldsProducers.length; readerIndex++) { |
| final FieldsProducer f = mergeState.fieldsProducers[readerIndex]; |
| |
| final int maxDoc = mergeState.maxDocs[readerIndex]; |
| f.checkIntegrity(); |
| slices.add(new ReaderSlice(docBase, maxDoc, readerIndex)); |
| fields.add(f); |
| docBase += maxDoc; |
| } |
| |
| Fields mergedFields = |
| new MappedMultiFields( |
| mergeState, |
| new MultiFields( |
| fields.toArray(Fields.EMPTY_ARRAY), slices.toArray(ReaderSlice.EMPTY_ARRAY))); |
| write(mergedFields, norms); |
| } |
| |
| // NOTE: strange but necessary so javadocs linting is happy: |
| @Override |
| public abstract void close() throws IOException; |
| } |