little-emotion commented on a change in pull request #241: Refactor the reader package for readability URL: https://github.com/apache/incubator-iotdb/pull/241#discussion_r303699612
########## File path: iotdb/src/main/java/org/apache/iotdb/db/query/reader/resourceRelated/SeqResourceIterateReader.java ########## @@ -0,0 +1,167 @@ +/** + * 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.iotdb.db.query.reader.resourceRelated; + +import java.io.IOException; +import java.util.Collections; +import java.util.List; +import org.apache.iotdb.db.engine.modification.Modification; +import org.apache.iotdb.db.engine.storagegroup.TsFileResource; +import org.apache.iotdb.db.query.context.QueryContext; +import org.apache.iotdb.db.query.control.FileReaderManager; +import org.apache.iotdb.db.query.reader.IAggregateReader; +import org.apache.iotdb.db.query.reader.fileRelated.FileSeriesReaderAdapter; +import org.apache.iotdb.db.query.reader.fileRelated.UnSealedTsFileIterateReader; +import org.apache.iotdb.db.query.reader.universal.IterateReader; +import org.apache.iotdb.db.utils.QueryUtils; +import org.apache.iotdb.tsfile.file.metadata.ChunkMetaData; +import org.apache.iotdb.tsfile.read.TsFileSequenceReader; +import org.apache.iotdb.tsfile.read.common.Path; +import org.apache.iotdb.tsfile.read.controller.ChunkLoader; +import org.apache.iotdb.tsfile.read.controller.ChunkLoaderImpl; +import org.apache.iotdb.tsfile.read.controller.MetadataQuerierByFileImpl; +import org.apache.iotdb.tsfile.read.filter.basic.Filter; +import org.apache.iotdb.tsfile.read.reader.series.FileSeriesReader; +import org.apache.iotdb.tsfile.read.reader.series.FileSeriesReaderWithFilter; +import org.apache.iotdb.tsfile.read.reader.series.FileSeriesReaderWithoutFilter; + +/** + * To read a chronologically ordered list of sequence TsFiles, this class extends {@link + * IterateReader} to implements <code>IAggregateReader</code> for the TsFiles. + * <p> + * Notes: 1) The list of sequence TsFiles is in strict chronological order. 2) The data in a + * sequence TsFile is also organized in chronological order. 3) A sequence TsFile can be either + * sealed or unsealed. 4) An unsealed sequence TsFile consists of two parts of data in chronological + * order: data that has been flushed to disk and data in the flushing memtable list. + * <p> + * This class is used in {@link org.apache.iotdb.db.query.reader.seriesRelated.SeriesReaderWithoutValueFilter}. + */ +public class SeqResourceIterateReader extends IterateReader { + + private Path seriesPath; + + /** + * Whether the reverse order is enabled. + * <p> + * True to iterate over the list of sequence TsFiles and chunks in TsFiles in reverse + * chronological order (from newest to oldest); False to iterate in chronological order (from + * oldest to newest). + */ + private boolean enableReverse; + + private List<TsFileResource> seqResources; + private Filter filter; + private QueryContext context; + + /** + * Constructor function. + * <p> + * <code>IterateReader</code> is used to iterate over the chronologically ordered list of + * sequence TsFiles. Therefore, this method calls the parent class <code>IterateReader</code>'s + * constructor to set <code>readerSize</code> to be the size of the TsFile list. Readers for the + * TsFiles are created in order later in the method <code>constructNextReader</code>. + * + * @param seriesPath the path of the series data + * @param seqResources a list of sequence TsFile resources in chronological order + * @param filter filter condition. Null if no filter. + * @param context query context + * @param isReverse True to iterate over data in reverse chronological order (from newest to + * oldest); False to iterate over data in chronological order (from oldest to newest). + */ + public SeqResourceIterateReader(Path seriesPath, List<TsFileResource> seqResources, + Filter filter, QueryContext context, boolean isReverse) { + super(seqResources.size()); + this.seriesPath = seriesPath; + this.enableReverse = isReverse; + if (isReverse) { + Collections.reverse(seqResources); + } + this.seqResources = seqResources; + this.filter = filter; + this.context = context; + } + + public SeqResourceIterateReader(Path seriesPath, List<TsFileResource> seqResources, + Filter timeFilter, QueryContext context) { + this(seriesPath, seqResources, timeFilter, context, false); + } + + @Override + public boolean constructNextReader(int idx) throws IOException { + TsFileResource tsFileResource = seqResources.get(idx); + if (tsFileResource.isClosed()) { + if (sealedTsFileSatisfied(tsFileResource, filter)) { + currentSeriesReader = initSealedTsFileReader(tsFileResource, filter, context); + return true; + } else { + return false; + } + } else { + currentSeriesReader = new UnSealedTsFileIterateReader(tsFileResource, filter, enableReverse); Review comment: Before building unsealed file reader, it's best to filter with startTime and endTime. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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