org.apache.druid.client.selector.RandomServerSelectorStrategy.java Source code

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Here is the source code for org.apache.druid.client.selector.RandomServerSelectorStrategy.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.druid.client.selector;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterators;
import com.google.common.collect.Lists;
import org.apache.druid.timeline.DataSegment;

import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ThreadLocalRandom;

public class RandomServerSelectorStrategy implements ServerSelectorStrategy {
    @Override
    public QueryableDruidServer pick(Set<QueryableDruidServer> servers, DataSegment segment) {
        return Iterators.get(servers.iterator(), ThreadLocalRandom.current().nextInt(servers.size()));
    }

    @Override
    public List<QueryableDruidServer> pick(Set<QueryableDruidServer> servers, DataSegment segment,
            int numServersToPick) {
        if (servers.size() <= numServersToPick) {
            return ImmutableList.copyOf(servers);
        }
        List<QueryableDruidServer> list = Lists.newArrayList(servers);
        Collections.shuffle(list, ThreadLocalRandom.current());
        return ImmutableList.copyOf(list.subList(0, numServersToPick));
    }
}