| /* |
| * 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.search.suggest.fst; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.util.Comparator; |
| |
| import org.apache.lucene.codecs.CodecUtil; |
| import org.apache.lucene.store.IOContext; |
| import org.apache.lucene.store.IndexOutput; |
| import org.apache.lucene.util.BytesRef; |
| import org.apache.lucene.util.BytesRefIterator; |
| import org.apache.lucene.util.IOUtils; |
| import org.apache.lucene.util.OfflineSorter; |
| |
| /** |
| * Builds and iterates over sequences stored on disk. |
| * @lucene.experimental |
| * @lucene.internal |
| */ |
| public class ExternalRefSorter implements BytesRefSorter, Closeable { |
| private final OfflineSorter sorter; |
| private OfflineSorter.ByteSequencesWriter writer; |
| private IndexOutput input; |
| private String sortedFileName; |
| |
| /** |
| * Will buffer all sequences to a temporary file and then sort (all on-disk). |
| */ |
| public ExternalRefSorter(OfflineSorter sorter) throws IOException { |
| this.sorter = sorter; |
| this.input = sorter.getDirectory().createTempOutput(sorter.getTempFileNamePrefix(), "RefSorterRaw", IOContext.DEFAULT); |
| this.writer = new OfflineSorter.ByteSequencesWriter(this.input); |
| } |
| |
| @Override |
| public void add(BytesRef utf8) throws IOException { |
| if (writer == null) { |
| throw new IllegalStateException(); |
| } |
| writer.write(utf8); |
| } |
| |
| @Override |
| public BytesRefIterator iterator() throws IOException { |
| if (sortedFileName == null) { |
| closeWriter(); |
| |
| boolean success = false; |
| try { |
| sortedFileName = sorter.sort(input.getName()); |
| success = true; |
| } finally { |
| if (success) { |
| sorter.getDirectory().deleteFile(input.getName()); |
| } else { |
| IOUtils.deleteFilesIgnoringExceptions(sorter.getDirectory(), input.getName()); |
| } |
| } |
| |
| input = null; |
| } |
| |
| return new ByteSequenceIterator(new OfflineSorter.ByteSequencesReader(sorter.getDirectory().openChecksumInput(sortedFileName, IOContext.READONCE), sortedFileName)); |
| } |
| |
| private void closeWriter() throws IOException { |
| if (writer != null) { |
| CodecUtil.writeFooter(input); |
| writer.close(); |
| writer = null; |
| } |
| } |
| |
| /** |
| * Removes any written temporary files. |
| */ |
| @Override |
| public void close() throws IOException { |
| try { |
| closeWriter(); |
| } finally { |
| IOUtils.deleteFilesIgnoringExceptions(sorter.getDirectory(), |
| input == null ? null : input.getName(), |
| sortedFileName); |
| } |
| } |
| |
| /** |
| * Iterate over byte refs in a file. |
| */ |
| // TODO: this class is a bit silly ... sole purpose is to "remove" Closeable from what #iterator returns: |
| static class ByteSequenceIterator implements BytesRefIterator { |
| private final OfflineSorter.ByteSequencesReader reader; |
| private BytesRef scratch; |
| |
| public ByteSequenceIterator(OfflineSorter.ByteSequencesReader reader) { |
| this.reader = reader; |
| } |
| |
| @Override |
| public BytesRef next() throws IOException { |
| boolean success = false; |
| try { |
| scratch = reader.next(); |
| if (scratch == null) { |
| reader.close(); |
| } |
| success = true; |
| return scratch; |
| } finally { |
| if (!success) { |
| IOUtils.closeWhileHandlingException(reader); |
| } |
| } |
| } |
| } |
| |
| @Override |
| public Comparator<BytesRef> getComparator() { |
| return sorter.getComparator(); |
| } |
| } |