com.facebook.presto.operator.PartitionGenerator.java Source code

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Here is the source code for com.facebook.presto.operator.PartitionGenerator.java

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/*
 * 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 com.facebook.presto.operator;

import com.facebook.presto.spi.Page;
import com.facebook.presto.spi.type.Type;
import com.google.common.collect.ImmutableList;

import java.util.List;
import java.util.Optional;

public interface PartitionGenerator {
    static PartitionGenerator createRoundRobinPartitionGenerator() {
        return new RoundRobinPartitionGenerator();
    }

    static PartitionGenerator createHashPartitionGenerator(Optional<Integer> hashChannel,
            List<Integer> partitioningChannels, List<Type> types) {
        if (hashChannel.isPresent()) {
            return new PrecomputedHashGenerator(hashChannel.get());
        }
        ImmutableList.Builder<Type> hashTypes = ImmutableList.builder();
        int[] hashChannels = new int[partitioningChannels.size()];
        for (int i = 0; i < partitioningChannels.size(); i++) {
            int channel = partitioningChannels.get(i);
            hashTypes.add(types.get(channel));
            hashChannels[i] = channel;
        }
        return new InterpretedHashGenerator(hashTypes.build(), hashChannels);
    }

    int getPartitionBucket(int partitionCount, int position, Page page);
}