io.druid.client.CacheUtil.java Source code

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Here is the source code for io.druid.client.CacheUtil.java

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/*
 * Druid - a distributed column store.
 * Copyright 2012 - 2015 Metamarkets Group 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 io.druid.client;

import com.fasterxml.jackson.databind.ObjectMapper;
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 = com.metamx.common.StringUtils.toUtf8(descriptor.getVersion());

        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);
        }
    }

}