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High performance primitives and utility library.

There is a newer version: 1.23.0

/*
 * Copyright 2014-2021 Real Logic Limited.
 *
 * 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
 *
 * https://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.agrona.concurrent;

import java.util.concurrent.locks.LockSupport;

/**
 * When idle this strategy is to sleep for a specified period in nanoseconds.
 * 
 * This class uses {@link LockSupport#parkNanos(long)} to idle.
 */
public final class SleepingIdleStrategy implements IdleStrategy
{
    /**
     * Name to be returned from {@link #alias()}.
     */
    public static final String ALIAS = "sleep-ns";

    /**
     * Default sleep period that tends to work as the likely minimum on Linux to be effective.
     */
    public static final long DEFAULT_SLEEP_PERIOD_NS = 1000L;

    private final long sleepPeriodNs;

    /**
     * Default constructor using {@link #DEFAULT_SLEEP_PERIOD_NS}.
     */
    public SleepingIdleStrategy()
    {
        sleepPeriodNs = DEFAULT_SLEEP_PERIOD_NS;
    }

    /**
     * Constructed a new strategy that will sleep for a given period when idle.
     *
     * @param sleepPeriodNs period in nanosecond for which the strategy will sleep when work count is 0.
     */
    public SleepingIdleStrategy(final long sleepPeriodNs)
    {
        this.sleepPeriodNs = sleepPeriodNs;
    }

    /**
     *  {@inheritDoc}
     */
    public void idle(final int workCount)
    {
        if (workCount > 0)
        {
            return;
        }

        LockSupport.parkNanos(sleepPeriodNs);
    }

    /**
     *  {@inheritDoc}
     */
    public void idle()
    {
        LockSupport.parkNanos(sleepPeriodNs);
    }

    /**
     *  {@inheritDoc}
     */
    public void reset()
    {
    }

    /**
     *  {@inheritDoc}
     */
    public String alias()
    {
        return ALIAS;
    }

    /**
     * {@inheritDoc}
     */
    public String toString()
    {
        return "SleepingIdleStrategy{" +
            "alias=" + ALIAS +
            ", sleepPeriodNs=" + sleepPeriodNs +
            '}';
    }
}