| /** |
| * 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.apex.malhar.lib.fileaccess; |
| |
| import java.io.IOException; |
| import java.util.TreeMap; |
| |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.fs.FSDataInputStream; |
| import org.apache.hadoop.io.file.tfile.DTFile; |
| import org.apache.hadoop.io.file.tfile.DTFile.Reader; |
| import org.apache.hadoop.io.file.tfile.DTFile.Reader.Scanner; |
| import org.apache.hadoop.io.file.tfile.DTFile.Reader.Scanner.Entry; |
| import org.apache.hadoop.io.file.tfile.TFile; |
| |
| import com.datatorrent.netlet.util.Slice; |
| |
| /** |
| * {@link DTFile} wrapper for HDSFileReader |
| * <br> |
| * {@link DTFile} has exact same format as {@link TFile} with a much faster {@link Reader} implementation |
| * <br> |
| * DTFileReader is also fully compatible with any file generated by {@link TFileWriter}. So there is no corresponding "DTFileWriter" |
| * |
| * |
| * @since 2.0.0 |
| */ |
| @InterfaceStability.Evolving |
| public class DTFileReader implements FileAccess.FileReader |
| { |
| private final Reader reader; |
| private final Scanner scanner; |
| private final FSDataInputStream fsdis; |
| |
| public DTFileReader(FSDataInputStream fsdis, long fileLength, Configuration conf) throws IOException |
| { |
| this.fsdis = fsdis; |
| reader = new Reader(fsdis, fileLength, conf); |
| scanner = reader.createScanner(); |
| } |
| |
| /** |
| * Unlike the TFile.Reader.close method this will close the wrapped InputStream. |
| * @see java.io.Closeable#close() |
| */ |
| @Override |
| public void close() throws IOException |
| { |
| scanner.close(); |
| reader.close(); |
| fsdis.close(); |
| } |
| |
| @Override |
| public void readFully(TreeMap<Slice, Slice> data) throws IOException |
| { |
| scanner.rewind(); |
| for (; !scanner.atEnd(); scanner.advance()) { |
| Entry en = scanner.entry(); |
| Slice key = new Slice(en.getBlockBuffer(), en.getKeyOffset(), en.getKeyLength()); |
| Slice value = new Slice(en.getBlockBuffer(), en.getValueOffset(), en.getValueLength()); |
| data.put(key, value); |
| } |
| |
| } |
| |
| @Override |
| public void reset() throws IOException |
| { |
| scanner.rewind(); |
| } |
| |
| @Override |
| public boolean seek(Slice key) throws IOException |
| { |
| return scanner.seekTo(key.buffer, key.offset, key.length); |
| } |
| |
| @Override |
| public boolean peek(Slice key, Slice value) throws IOException |
| { |
| if (scanner.atEnd()) { |
| return false; |
| } |
| Entry en = scanner.entry(); |
| |
| key.buffer = en.getBlockBuffer(); |
| key.offset = en.getKeyOffset(); |
| key.length = en.getKeyLength(); |
| |
| value.buffer = en.getBlockBuffer(); |
| value.offset = en.getValueOffset(); |
| value.length = en.getValueLength(); |
| |
| return true; |
| } |
| |
| @Override |
| public boolean next(Slice key, Slice value) throws IOException |
| { |
| if (peek(key, value)) { |
| scanner.advance(); |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| @Override |
| public boolean hasNext() |
| { |
| return !scanner.atEnd(); |
| } |
| } |