/*
* Druid - a distributed column store.
* Copyright (C) 2014 Metamarkets Group Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package io.druid.client;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Charsets;
import com.google.common.base.Throwables;
import com.google.common.collect.Lists;
import io.druid.client.cache.Cache;
import io.druid.query.SegmentDescriptor;
import org.joda.time.Interval;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.List;
public class CacheUtil
{
public static Cache.NamedKey computeSegmentCacheKey(
String segmentIdentifier,
SegmentDescriptor descriptor,
byte[] queryCacheKey
)
{
final Interval segmentQueryInterval = descriptor.getInterval();
final byte[] versionBytes = descriptor.getVersion().getBytes(Charsets.UTF_8);
return new Cache.NamedKey(
segmentIdentifier, ByteBuffer
.allocate(16 + versionBytes.length + 4 + queryCacheKey.length)
.putLong(segmentQueryInterval.getStartMillis())
.putLong(segmentQueryInterval.getEndMillis())
.put(versionBytes)
.putInt(descriptor.getPartitionNumber())
.put(queryCacheKey).array()
);
}
public static void populate(Cache cache, ObjectMapper mapper, Cache.NamedKey key, Iterable<Object> results)
{
try {
List<byte[]> bytes = Lists.newArrayList();
int size = 0;
for (Object result : results) {
final byte[] array = mapper.writeValueAsBytes(result);
size += array.length;
bytes.add(array);
}
byte[] valueBytes = new byte[size];
int offset = 0;
for (byte[] array : bytes) {
System.arraycopy(array, 0, valueBytes, offset, array.length);
offset += array.length;
}
cache.put(key, valueBytes);
}
catch (IOException e) {
throw Throwables.propagate(e);
}
}
}