/*
* Copyright © 2016 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.coprocessor.hbase12cdh570;
import co.cask.cdap.data2.queue.ConsumerConfig;
import co.cask.cdap.data2.transaction.queue.QueueEntryRow;
import co.cask.cdap.data2.transaction.queue.hbase.DequeueScanAttributes;
import co.cask.tephra.Transaction;
import com.google.common.primitives.Ints;
import com.google.common.primitives.Longs;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.exceptions.DeserializationException;
import org.apache.hadoop.hbase.filter.Filter;
import org.apache.hadoop.hbase.filter.FilterBase;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.List;
/**
* Server-side filter for dequeue operation
*/
// todo: unit-test it (without DequeueScanObserver)
public class DequeueFilter extends FilterBase {
private ConsumerConfig consumerConfig;
private Transaction transaction;
private byte[] stateColumnName;
private boolean stopScan;
private boolean skipRow;
private int counter;
private long writePointer;
// For Writable
private DequeueFilter() {
}
public DequeueFilter(ConsumerConfig consumerConfig, Transaction transaction) {
this.consumerConfig = consumerConfig;
this.transaction = transaction;
this.stateColumnName = Bytes.add(QueueEntryRow.STATE_COLUMN_PREFIX,
Bytes.toBytes(consumerConfig.getGroupId()));
}
@Override
public void reset() throws IOException {
stopScan = false;
skipRow = false;
}
@Override
public boolean filterAllRemaining() {
return stopScan;
}
@Override
public boolean filterRowKey(byte[] buffer, int offset, int length) {
// last 4 bytes in a row key
counter = Bytes.toInt(buffer, offset + length - Ints.BYTES, Ints.BYTES);
// row key is queue_name + writePointer + counter
writePointer = Bytes.toLong(buffer, offset + length - Longs.BYTES - Ints.BYTES, Longs.BYTES);
// If writes later than the reader pointer, abort the loop, as entries that comes later are all uncommitted.
// this is probably not needed due to the limit of the scan to the stop row, but to be safe...
if (writePointer > transaction.getReadPointer()) {
stopScan = true;
return true;
}
// If the write is in the excluded list, ignore it.
if (transaction.isExcluded(writePointer)) {
return true;
}
return false;
}
@Override
public boolean hasFilterRow() {
return true;
}
@Override
public void filterRowCells(List<Cell> cells) {
byte[] dataBytes = null;
byte[] metaBytes = null;
byte[] stateBytes = null;
// list is very short so it is ok to loop thru to find columns
for (Cell cell : cells) {
if (CellUtil.matchingQualifier(cell, QueueEntryRow.DATA_COLUMN)) {
dataBytes = CellUtil.cloneValue(cell);
} else if (CellUtil.matchingQualifier(cell, QueueEntryRow.META_COLUMN)) {
metaBytes = CellUtil.cloneValue(cell);
} else if (CellUtil.matchingQualifier(cell, stateColumnName)) {
stateBytes = CellUtil.cloneValue(cell);
}
}
if (dataBytes == null || metaBytes == null) {
skipRow = true;
return;
}
QueueEntryRow.CanConsume canConsume =
QueueEntryRow.canConsume(consumerConfig, transaction, writePointer, counter, metaBytes, stateBytes);
// Only skip the row when canConsumer == NO, so that in case of NO_INCLUDING_ALL_OLDER, the client
// can still see the row and move the scan start row.
skipRow = canConsume == QueueEntryRow.CanConsume.NO;
}
@Override
public ReturnCode filterKeyValue(Cell cell) throws IOException {
return ReturnCode.INCLUDE;
}
@Override
public boolean filterRow() {
return skipRow;
}
/* Writable implementation for HBase 0.94 */
public void write(DataOutput out) throws IOException {
DequeueScanAttributes.write(out, consumerConfig);
DequeueScanAttributes.write(out, transaction);
}
public void readFields(DataInput in) throws IOException {
this.consumerConfig = DequeueScanAttributes.readConsumerConfig(in);
this.transaction = DequeueScanAttributes.readTx(in);
}
/* Serialization support for HBase 0.98+ */
public byte[] toByteArray() throws IOException {
// TODO: in the future actual serialization here should be done using protobufs
ByteArrayOutputStream bos = new ByteArrayOutputStream();
write(new DataOutputStream(bos));
return bos.toByteArray();
}
public static Filter parseFrom(final byte [] pbBytes) throws DeserializationException {
DequeueFilter filter = new DequeueFilter();
try {
filter.readFields(new DataInputStream(new ByteArrayInputStream(pbBytes)));
} catch (IOException ioe) {
throw new DeserializationException(ioe);
}
return filter;
}
}