io.trino.operator.exchange.RandomExchanger Maven / Gradle / Ivy

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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 io.trino.operator.exchange;

import com.google.common.collect.ImmutableList;
import com.google.common.util.concurrent.ListenableFuture;
import io.trino.spi.Page;

import java.util.List;
import java.util.concurrent.ThreadLocalRandom;
import java.util.function.Consumer;

import static java.util.Objects.requireNonNull;

class RandomExchanger
        implements LocalExchanger
{
    private final List> buffers;
    private final LocalExchangeMemoryManager memoryManager;

    public RandomExchanger(List> buffers, LocalExchangeMemoryManager memoryManager)
    {
        this.buffers = ImmutableList.copyOf(requireNonNull(buffers, "buffers is null"));
        this.memoryManager = requireNonNull(memoryManager, "memoryManager is null");
    }

    @Override
    public void accept(Page page)
    {
        memoryManager.updateMemoryUsage(page.getRetainedSizeInBytes());
        int randomIndex = ThreadLocalRandom.current().nextInt(buffers.size());
        buffers.get(randomIndex).accept(page);
    }

    @Override
    public ListenableFuture waitForWriting()
    {
        return memoryManager.getNotFullFuture();
    }
}