/**
* 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.drill.exec.store.mongo;
import java.util.List;
import org.apache.drill.common.exceptions.ExecutionSetupException;
import org.apache.drill.common.expression.SchemaPath;
import org.apache.drill.exec.ops.FragmentContext;
import org.apache.drill.exec.physical.base.GroupScan;
import org.apache.drill.exec.physical.impl.BatchCreator;
import org.apache.drill.exec.physical.impl.ScanBatch;
import org.apache.drill.exec.record.RecordBatch;
import org.apache.drill.exec.store.RecordReader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.mongodb.MongoClientOptions;
public class MongoScanBatchCreator implements BatchCreator<MongoSubScan> {
static final Logger logger = LoggerFactory
.getLogger(MongoScanBatchCreator.class);
@Override
public RecordBatch getBatch(FragmentContext context, MongoSubScan subScan,
List<RecordBatch> children) throws ExecutionSetupException {
Preconditions.checkArgument(children.isEmpty());
List<RecordReader> readers = Lists.newArrayList();
List<SchemaPath> columns = null;
for (MongoSubScan.MongoSubScanSpec scanSpec : subScan
.getChunkScanSpecList()) {
try {
if ((columns = subScan.getColumns()) == null) {
columns = GroupScan.ALL_COLUMNS;
}
MongoClientOptions clientOptions = subScan.getMongoPluginConfig()
.getMongoOptions();
readers.add(new MongoRecordReader(scanSpec, columns, context,
clientOptions));
} catch (Exception e) {
logger.error("MongoRecordReader creation failed for subScan: "
+ subScan + ".");
logger.error(e.getMessage(), e);
throw new ExecutionSetupException(e);
}
}
logger.info("Number of record readers initialized : " + readers.size());
return new ScanBatch(subScan, context, readers.iterator());
}
}