/*
* 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 gobblin.source.extractor.hadoop;
import java.io.IOException;
import java.util.Iterator;
import org.apache.avro.Schema;
import org.apache.avro.generic.GenericRecord;
import com.google.common.base.Throwables;
import gobblin.configuration.ConfigurationKeys;
import gobblin.configuration.WorkUnitState;
import gobblin.source.extractor.filebased.FileBasedExtractor;
import gobblin.source.extractor.filebased.FileBasedHelperException;
/**
* A custom type of {@link FileBasedExtractor}s for extracting data from Avro files.
*/
public class AvroFileExtractor extends FileBasedExtractor<Schema, GenericRecord> {
public AvroFileExtractor(WorkUnitState workUnitState) {
super(workUnitState, new AvroFsHelper(workUnitState));
}
@Override
public Iterator<GenericRecord> downloadFile(String file) throws IOException {
try {
return this.closer.register(((AvroFsHelper) this.fsHelper).getAvroFile(file));
} catch (FileBasedHelperException e) {
Throwables.propagate(e);
}
return null;
}
/**
* Assumption is that all files in the input directory have the same schema
*/
@Override
public Schema getSchema() {
if (this.workUnit.contains(ConfigurationKeys.SOURCE_SCHEMA)) {
return new Schema.Parser().parse(this.workUnit.getProp(ConfigurationKeys.SOURCE_SCHEMA));
}
AvroFsHelper hfsHelper = (AvroFsHelper) this.fsHelper;
if (this.filesToPull.isEmpty()) {
return null;
}
try {
return hfsHelper.getAvroSchema(this.filesToPull.get(0));
} catch (FileBasedHelperException e) {
Throwables.propagate(e);
return null;
}
}
}