com.sportradar.unifiedodds.sdk.impl.IncrementalSequenceGenerator Maven / Gradle / Ivy

/*
 * Copyright (C) Sportradar AG. See LICENSE for full license governing this code
 */

package com.sportradar.unifiedodds.sdk.impl;

import com.google.common.base.Preconditions;

import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;


/**
 * A class used to provide distinct incremented values between specified min & max value
 */
public class IncrementalSequenceGenerator implements SequenceGenerator {

    /**
     * The minimum value returned by the current instance
     */
    private final int minValue;

    /**
     * The maximum value returned by the current instance
     */
    private final int maxValue;

    /**
     * A {@link AtomicLong} used to used to get the next value in a thread safe manner
     */
    private final AtomicInteger current;

    /**
     * Initializes a new instance of the {@link IncrementalSequenceGenerator}
     * @param minValue The minimum value returned by the initialized instance
     * @param maxValue The maximum value returned by the initialized instance
     */
    public IncrementalSequenceGenerator(int minValue, int maxValue){
        Preconditions.checkArgument(maxValue > minValue, "maxValue must be greater than minValue");

        this.minValue = minValue;
        this.maxValue = maxValue;

        current = new AtomicInteger(minValue);
    }

    /**
     * Gets the next available distinct value
     * @return the next available distinct value
     */
    public int getNext(){
        int currentValue;
        int nextValue;

        do{
            currentValue = current.get();
            nextValue = currentValue < maxValue
                    ? currentValue + 1
                    : minValue;
        }while(!current.compareAndSet(currentValue,  nextValue));

        return nextValue;
    }
}