| /** |
| * 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.crunch.types.avro; |
| |
| import java.io.IOException; |
| |
| import org.apache.avro.Schema; |
| import org.apache.avro.file.DataFileReader; |
| import org.apache.avro.file.FileReader; |
| import org.apache.avro.file.SeekableInput; |
| import org.apache.avro.io.DatumReader; |
| import org.apache.avro.mapred.AvroWrapper; |
| import org.apache.avro.mapred.FsInput; |
| import org.apache.hadoop.conf.Configuration; |
| 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; |
| |
| /** An {@link RecordReader} for Avro data files. */ |
| class AvroRecordReader<T> extends RecordReader<AvroWrapper<T>, NullWritable> { |
| |
| private FileReader<T> reader; |
| private long start; |
| private long end; |
| private AvroWrapper<T> key; |
| private NullWritable value; |
| private Schema schema; |
| |
| public AvroRecordReader(Schema schema) { |
| this.schema = schema; |
| } |
| |
| @Override |
| public void initialize(InputSplit genericSplit, TaskAttemptContext context) throws IOException, InterruptedException { |
| FileSplit split = (FileSplit) genericSplit; |
| Configuration conf = context.getConfiguration(); |
| SeekableInput in = new FsInput(split.getPath(), conf); |
| DatumReader<T> datumReader = AvroMode |
| .fromConfiguration(context.getConfiguration()) |
| .getReader(schema); |
| this.reader = DataFileReader.openReader(in, datumReader); |
| reader.sync(split.getStart()); // sync to start |
| this.start = reader.tell(); |
| this.end = split.getStart() + split.getLength(); |
| } |
| |
| @Override |
| public boolean nextKeyValue() throws IOException, InterruptedException { |
| if (!reader.hasNext() || reader.pastSync(end)) { |
| key = null; |
| value = null; |
| return false; |
| } |
| if (key == null) { |
| key = new AvroWrapper<T>(); |
| } |
| if (value == null) { |
| value = NullWritable.get(); |
| } |
| key.datum(reader.next(key.datum())); |
| return true; |
| } |
| |
| @Override |
| public AvroWrapper<T> getCurrentKey() throws IOException, InterruptedException { |
| return key; |
| } |
| |
| @Override |
| public NullWritable getCurrentValue() throws IOException, InterruptedException { |
| return value; |
| } |
| |
| @Override |
| public float getProgress() throws IOException { |
| if (end == start) { |
| return 0.0f; |
| } else { |
| return Math.min(1.0f, (getPos() - start) / (float) (end - start)); |
| } |
| } |
| |
| public long getPos() throws IOException { |
| return reader.tell(); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| if (reader != null) { |
| reader.close(); |
| reader = null; |
| } |
| } |
| } |