gaoyunhaii commented on a change in pull request #16: URL: https://github.com/apache/flink-ml/pull/16#discussion_r739941592
########## File path: flink-ml-iteration/src/main/java/org/apache/flink/iteration/datacache/nonkeyed/DataCacheReader.java ########## @@ -0,0 +1,118 @@ +/* + * 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.api.common.typeutils.TypeSerializer; +import org.apache.flink.core.fs.FSDataInputStream; +import org.apache.flink.core.fs.FileSystem; +import org.apache.flink.core.memory.DataInputView; +import org.apache.flink.core.memory.DataInputViewStreamWrapper; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.Iterator; +import java.util.List; + +import static org.apache.flink.util.Preconditions.checkArgument; + +/** Reads the cached data from a list of paths. */ +public class DataCacheReader<T> implements Iterator<T> { + + private final TypeSerializer<T> serializer; + + private final FileSystem fileSystem; + + private final List<Segment> segments; + + @Nullable private SegmentReader currentSegmentReader; + + public DataCacheReader( + TypeSerializer<T> serializer, FileSystem fileSystem, List<Segment> segments) + throws IOException { + + for (Segment segment : segments) { + checkArgument(segment.getCount() > 0, "Do not support empty segment"); + } + + this.serializer = serializer; + this.fileSystem = fileSystem; + this.segments = segments; + + if (segments.size() > 0) { + this.currentSegmentReader = new SegmentReader(0); + } + } + + @Override + public boolean hasNext() { + return currentSegmentReader != null && currentSegmentReader.hasNext(); + } + + @Override + public T next() { + try { + T next = currentSegmentReader.next(); + + if (!currentSegmentReader.hasNext()) { + currentSegmentReader.close(); + if (currentSegmentReader.index < segments.size() - 1) { + currentSegmentReader = new SegmentReader(currentSegmentReader.index + 1); + } else { + currentSegmentReader = null; + } + } + + return next; + } catch (IOException e) { + throw new RuntimeException(e); + } + } + + private class SegmentReader { + + private final int index; + + private final FSDataInputStream inputStream; + + private final DataInputView inputView; + + private int offset; + + public SegmentReader(int index) throws IOException { + this.index = index; + inputStream = fileSystem.open(segments.get(index).getPath()); + inputView = new DataInputViewStreamWrapper(inputStream); + } + + public boolean hasNext() { + return offset < segments.get(index).getCount(); Review comment: `offset` should be the position of the next record ? -- 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
