| /* |
| * 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.util.avro; |
| |
| import java.io.IOException; |
| import java.util.NoSuchElementException; |
| |
| import org.apache.avro.Schema; |
| import org.apache.avro.file.DataFileReader; |
| import org.apache.avro.file.FileReader; |
| import org.apache.avro.generic.GenericData; |
| import org.apache.avro.generic.GenericDatumReader; |
| import org.apache.avro.io.DatumReader; |
| import org.apache.avro.mapred.FsInput; |
| import org.apache.hadoop.io.NullWritable; |
| 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; |
| |
| |
| /** |
| * RecordReader for Avro files |
| */ |
| public final class AvroRecordReader |
| extends RecordReader<NullWritable, GenericData.Record> { |
| |
| private FileReader<GenericData.Record> reader; |
| private long start; |
| private long end; |
| private Schema schema; |
| private GenericData.Record currentRecord; |
| |
| /** |
| * Creates new instance of AvroRecordReader. |
| * @param s The input schema. |
| */ |
| public AvroRecordReader(final Schema s) { |
| schema = s; |
| } |
| |
| @Override |
| public void close() throws IOException { |
| reader.close(); |
| } |
| |
| /** |
| * Returns current value. |
| * @return the current value |
| * @throws IOException when an IO error occurs |
| * @throws InterruptedException when interrupted |
| */ |
| @Override |
| public GenericData.Record getCurrentValue() |
| throws IOException, InterruptedException { |
| if (currentRecord != null) { |
| return currentRecord; |
| } else { |
| return null; |
| } |
| } |
| |
| @Override |
| public NullWritable getCurrentKey() |
| throws IOException, InterruptedException { |
| return NullWritable.get(); |
| } |
| |
| @Override |
| public float getProgress() throws IOException, InterruptedException { |
| if (start == end) { |
| return 0.0f; |
| } else { |
| return Math.min(1.0f, |
| ((float) (reader.tell() - start)) / ((float) (end - start))); |
| } |
| } |
| |
| @Override |
| public void initialize(final InputSplit isplit, final TaskAttemptContext tc) |
| throws IOException, InterruptedException { |
| |
| FileSplit fsplit = (FileSplit) isplit; |
| start = fsplit.getStart(); |
| end = fsplit.getStart() + fsplit.getLength(); |
| DatumReader<GenericData.Record> datumReader |
| = new GenericDatumReader<GenericData.Record>(schema); |
| reader = DataFileReader.openReader( |
| new FsInput(fsplit.getPath(), tc.getConfiguration()), |
| datumReader); |
| reader.sync(start); |
| } |
| |
| @Override |
| public boolean nextKeyValue() throws IOException, InterruptedException { |
| |
| if (reader.pastSync(end)) { |
| return false; |
| } |
| |
| try { |
| currentRecord = reader.next(new GenericData.Record(schema)); |
| } catch (NoSuchElementException e) { |
| return false; |
| } catch (IOException ioe) { |
| reader.sync(reader.tell()+1); |
| throw ioe; |
| } |
| |
| return true; |
| } |
| |
| } |