/*
* 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.leveldb;
import co.cask.cdap.api.common.Bytes;
import co.cask.cdap.common.queue.QueueName;
import co.cask.cdap.data2.dataset2.lib.table.leveldb.KeyValue;
import co.cask.cdap.data2.dataset2.lib.table.leveldb.LevelDBTableCore;
import co.cask.cdap.data2.queue.QueueEntry;
import co.cask.cdap.data2.transaction.queue.AbstractQueueProducer;
import co.cask.cdap.data2.transaction.queue.QueueEntryRow;
import co.cask.cdap.data2.transaction.queue.QueueMetrics;
import co.cask.tephra.Transaction;
import com.google.common.collect.Maps;
import java.util.NavigableMap;
/**
* A queue producer for levelDB.
*/
public final class LevelDBQueueProducer extends AbstractQueueProducer {
private final LevelDBTableCore core;
private final byte[] queueRowPrefix;
private final NavigableMap<byte[], NavigableMap<byte[], byte[]>> changes;
public LevelDBQueueProducer(LevelDBTableCore tableCore, QueueName queueName, QueueMetrics queueMetrics) {
super(queueMetrics, queueName);
core = tableCore;
changes = Maps.newTreeMap(Bytes.BYTES_COMPARATOR);
queueRowPrefix = QueueEntryRow.getQueueRowPrefix(queueName);
}
@Override
public void startTx(Transaction tx) {
super.startTx(tx);
changes.clear();
}
@Override
protected int persist(Iterable<QueueEntry> entries, Transaction transaction) throws Exception {
long writePointer = transaction.getWritePointer();
byte[] rowKeyPrefix = Bytes.add(queueRowPrefix, Bytes.toBytes(writePointer));
int count = 0;
int bytes = 0;
for (QueueEntry entry : entries) {
// Row key = queue_name + writePointer + counter
byte[] rowKey = Bytes.add(rowKeyPrefix, Bytes.toBytes(count++));
NavigableMap<byte[], byte[]> row = Maps.newTreeMap(Bytes.BYTES_COMPARATOR);
row.put(QueueEntryRow.DATA_COLUMN, entry.getData());
row.put(QueueEntryRow.META_COLUMN, QueueEntry.serializeHashKeys(entry.getHashKeys()));
changes.put(rowKey, row);
bytes += entry.getData().length;
}
// TODO introduce a constant in the OcTableCore for the latest timestamp
core.persist(changes, KeyValue.LATEST_TIMESTAMP);
return bytes;
}
@Override
protected void doRollback() throws Exception {
core.undo(changes, KeyValue.LATEST_TIMESTAMP);
}
}