yunfengzhou-hub commented on code in PR #97: URL: https://github.com/apache/flink-ml/pull/97#discussion_r890701650
########## flink-ml-iteration/src/main/java/org/apache/flink/iteration/datacache/nonkeyed/FileSegmentWriter.java: ########## @@ -0,0 +1,89 @@ +/* + * 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.flink.iteration.datacache.nonkeyed; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.core.fs.FSDataOutputStream; +import org.apache.flink.core.fs.FileSystem; +import org.apache.flink.core.fs.Path; +import org.apache.flink.core.memory.DataOutputView; +import org.apache.flink.core.memory.DataOutputViewStreamWrapper; + +import java.io.BufferedOutputStream; +import java.io.IOException; +import java.util.Optional; + +/** A class that writes cache data to a target file in given file system. */ +@Internal +class FileSegmentWriter<T> implements SegmentWriter<T> { + + /** The tool to serialize received records into bytes. */ + private final TypeSerializer<T> serializer; + + /** The path to the target file. */ + private final Path path; + + /** The output stream that writes to the target file. */ + private final FSDataOutputStream outputStream; + + /** A buffer that wraps the output stream to optimize performance. */ + private final BufferedOutputStream bufferedOutputStream; + + /** The wrapper view of output stream to be used with TypeSerializer API. */ + private final DataOutputView outputView; + + /** The number of records added so far. */ + private int count; + + FileSegmentWriter(TypeSerializer<T> serializer, Path path) throws IOException { + this.serializer = serializer; + this.path = path; + this.outputStream = path.getFileSystem().create(path, FileSystem.WriteMode.NO_OVERWRITE); + this.bufferedOutputStream = new BufferedOutputStream(outputStream); + this.outputView = new DataOutputViewStreamWrapper(bufferedOutputStream); + } + + @Override + public boolean addRecord(T record) throws IOException { + if (outputStream.getPos() >= DataCacheWriter.MAX_SEGMENT_SIZE) { + return false; + } + serializer.serialize(record, outputView); + count++; + return true; + } + + @Override + public Optional<Segment> finish() throws IOException { + bufferedOutputStream.flush(); Review Comment: `bufferedOutputStream` wraps around `outputStream` and is invisible to `outputStream`. When `outputStream.flush()` is invoked, there might be some bytes left in `bufferedOutputStream`. When I tried to remove this line, most data cache tests failed. Thus this line cannot be removed. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
