/*
* Copyright © 2014-2015 Cask Data, Inc.
*
* Licensed 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 co.cask.cdap.data2.dataset2.lib.table.hbase;
import co.cask.cdap.api.dataset.table.Row;
import co.cask.cdap.api.dataset.table.Scanner;
import com.google.common.base.Throwables;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import java.io.IOException;
import java.util.Map;
/**
* Implements Scanner on top of HBase resultSetScanner.
*/
public class HBaseScanner implements Scanner {
private final ResultScanner scanner;
private final byte[] columnFamily;
public HBaseScanner(ResultScanner scanner, byte[] columnFamily) {
this.scanner = scanner;
this.columnFamily = columnFamily;
}
@Override
public Row next() {
if (scanner == null) {
return null;
}
try {
//Loop until one row is read completely or until end is reached.
while (true) {
Result result = scanner.next();
if (result == null || result.isEmpty()) {
break;
}
Map<byte[], byte[]> rowMap = HBaseTable.getRowMap(result, columnFamily);
if (rowMap.size() > 0) {
return new co.cask.cdap.api.dataset.table.Result(result.getRow(), rowMap);
}
}
// exhausted
return null;
} catch (IOException e) {
throw Throwables.propagate(e);
}
}
@Override
public void close() {
scanner.close();
}
}