com.digitalpetri.netty.fsm.Scheduler Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of netty-channel-fsm Show documentation

A state machine that manages async non-blocking access to a Netty Channel.

There is a newer version: 1.0.0-RC2

/*
 * Copyright 2018 Kevin Herron
 *
 * 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.digitalpetri.netty.fsm;

import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

public interface Scheduler {

    /**
     * Schedule a command to run after a {@code delay}.
     *
     * @param command the commadn to run.
     * @param delay   the time to delay.
     * @param unit    the time unit of the delay.
     * @return a {@link Cancellable} that can be used to attempt cancellation if needed.
     */
    Cancellable schedule(Runnable command, long delay, TimeUnit unit);

    interface Cancellable {

        /**
         * Attempt to cancel a scheduled command.
         *
         * @return {@code true} if the command was canceled.
         */
        boolean cancel();

    }

    /**
     * Create a {@link Scheduler} from the provided {@link ScheduledExecutorService}.
     *
     * @param scheduledExecutor a {@link ScheduledExecutorService}.
     * @return a {@link Scheduler}.
     */
    static Scheduler fromScheduledExecutor(ScheduledExecutorService scheduledExecutor) {
        return (command, delay, unit) -> {
            ScheduledFuture future = scheduledExecutor.schedule(command, delay, unit);

            return () -> future.cancel(false);
        };
    }

}