| /* |
| * 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.pig.impl.io; |
| |
| import java.io.DataInputStream; |
| import java.io.IOException; |
| |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.fs.FSDataInputStream; |
| import org.apache.hadoop.fs.FileSystem; |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.io.Text; |
| import org.apache.hadoop.mapreduce.InputSplit; |
| import org.apache.hadoop.mapreduce.RecordReader; |
| import org.apache.hadoop.mapreduce.TaskAttemptContext; |
| import org.apache.hadoop.mapreduce.lib.input.FileSplit; |
| import org.apache.pig.backend.executionengine.ExecException; |
| import org.apache.pig.data.BinInterSedes; |
| import org.apache.pig.data.InterSedes; |
| import org.apache.pig.data.InterSedesFactory; |
| import org.apache.pig.data.Tuple; |
| |
| /** |
| * A record reader used to read data written using {@link InterRecordWriter} |
| * It uses the default InterSedes object for deserialization. |
| */ |
| public class InterRecordReader extends RecordReader<Text, Tuple> { |
| |
| private long start; |
| private long pos; |
| private long end; |
| private BufferedPositionedInputStream in; |
| private Tuple value = null; |
| public static final int RECORD_1 = 0x01; |
| public static final int RECORD_2 = 0x02; |
| public static final int RECORD_3 = 0x03; |
| private DataInputStream inData = null; |
| private static InterSedes sedes = InterSedesFactory.getInterSedesInstance(); |
| |
| public void initialize(InputSplit genericSplit, |
| TaskAttemptContext context) throws IOException { |
| FileSplit split = (FileSplit) genericSplit; |
| Configuration job = context.getConfiguration(); |
| start = split.getStart(); |
| end = start + split.getLength(); |
| final Path file = split.getPath(); |
| |
| // open the file and seek to the start of the split |
| FileSystem fs = file.getFileSystem(job); |
| FSDataInputStream fileIn = fs.open(split.getPath()); |
| if (start != 0) { |
| fileIn.seek(start); |
| } |
| in = new BufferedPositionedInputStream(fileIn, start); |
| inData = new DataInputStream(in); |
| } |
| |
| public boolean nextKeyValue() throws IOException { |
| int b = 0; |
| // skip to next record |
| while (true) { |
| if (in == null || in.getPosition() >=end) { |
| return false; |
| } |
| // check if we saw RECORD_1 in our last attempt |
| // this can happen if we have the following |
| // sequence RECORD_1-RECORD_1-RECORD_2-RECORD_3 |
| // After reading the second RECORD_1 in the above |
| // sequence, we should not look for RECORD_1 again |
| if(b != RECORD_1) { |
| b = in.read(); |
| if(b != RECORD_1 && b != -1) { |
| continue; |
| } |
| if(b == -1) return false; |
| } |
| b = in.read(); |
| if(b != RECORD_2 && b != -1) { |
| continue; |
| } |
| if(b == -1) return false; |
| b = in.read(); |
| if(b != RECORD_3 && b != -1) { |
| continue; |
| } |
| if(b == -1) return false; |
| b = in.read(); |
| if(!BinInterSedes.isTupleByte((byte) b) && |
| b != -1) { |
| continue; |
| } |
| if(b == -1) return false; |
| break; |
| } |
| try { |
| // if we got here, we have seen RECORD_1-RECORD_2-RECORD_3-TUPLE_MARKER |
| // sequence - lets now read the contents of the tuple |
| value = (Tuple)sedes.readDatum(inData, (byte)b); |
| pos=in.getPosition(); |
| return true; |
| } catch (ExecException ee) { |
| throw ee; |
| } |
| |
| } |
| |
| @Override |
| public Text getCurrentKey() { |
| // the key is always null since we don't really have a key for each |
| // input record |
| return null; |
| } |
| |
| @Override |
| public Tuple getCurrentValue() { |
| return value; |
| } |
| |
| /** |
| * Get the progress within the split |
| */ |
| public float getProgress() { |
| if (start == end) { |
| return 0.0f; |
| } else { |
| return Math.min(1.0f, (pos - start) / (float)(end - start)); |
| } |
| } |
| |
| public synchronized void close() throws IOException { |
| if (in != null) { |
| in.close(); |
| } |
| } |
| } |