/*
* Copyright © 2014 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.transaction.queue.hbase;
import co.cask.cdap.api.common.Bytes;
import co.cask.cdap.common.queue.QueueName;
import co.cask.cdap.data2.queue.ConsumerConfig;
import co.cask.cdap.data2.transaction.queue.ConsumerEntryState;
import co.cask.cdap.data2.transaction.queue.QueueEntryRow;
import com.google.common.primitives.Ints;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.filter.BinaryPrefixComparator;
import org.apache.hadoop.hbase.filter.BitComparator;
import org.apache.hadoop.hbase.filter.CompareFilter;
import org.apache.hadoop.hbase.filter.Filter;
import org.apache.hadoop.hbase.filter.FilterList;
import org.apache.hadoop.hbase.filter.SingleColumnValueFilter;
/**
* HBase 0.94 implementation of {@link HBaseQueueConsumer}.
*/
final class HBase94QueueConsumer extends HBaseQueueConsumer {
private final Filter processedStateFilter;
HBase94QueueConsumer(ConsumerConfig consumerConfig, HTable hTable, QueueName queueName,
HBaseConsumerState consumerState, HBaseConsumerStateStore stateStore) {
super(consumerConfig, hTable, queueName, consumerState, stateStore);
processedStateFilter = createStateFilter();
}
@Override
protected Scan createScan(byte[] startRow, byte[] stopRow, int numRows) {
// Scan the table for queue entries.
Scan scan = new Scan();
// we should roughly divide by number of buckets, but don't want another RPC for the case we are not exactly right
int caching = (int) (1.1 * numRows / HBaseQueueAdmin.ROW_KEY_DISTRIBUTION_BUCKETS);
scan.setCaching(caching);
scan.setStartRow(startRow);
scan.setStopRow(stopRow);
scan.addColumn(QueueEntryRow.COLUMN_FAMILY, QueueEntryRow.DATA_COLUMN);
scan.addColumn(QueueEntryRow.COLUMN_FAMILY, QueueEntryRow.META_COLUMN);
scan.addColumn(QueueEntryRow.COLUMN_FAMILY, stateColumnName);
scan.setFilter(createFilter());
scan.setMaxVersions(1);
return scan;
}
/**
* Creates a HBase filter that will filter out rows that that has committed state = PROCESSED.
*/
private Filter createFilter() {
return new FilterList(FilterList.Operator.MUST_PASS_ONE, processedStateFilter, new SingleColumnValueFilter(
QueueEntryRow.COLUMN_FAMILY, stateColumnName, CompareFilter.CompareOp.GREATER,
new BinaryPrefixComparator(Bytes.toBytes(transaction.getReadPointer()))
));
}
/**
* Creates a HBase filter that will filter out rows with state column state = PROCESSED (ignoring transaction).
*/
private Filter createStateFilter() {
byte[] processedMask = new byte[Ints.BYTES * 2 + 1];
processedMask[processedMask.length - 1] = ConsumerEntryState.PROCESSED.getState();
return new SingleColumnValueFilter(QueueEntryRow.COLUMN_FAMILY, stateColumnName,
CompareFilter.CompareOp.NOT_EQUAL,
new BitComparator(processedMask, BitComparator.BitwiseOp.AND));
}
}