Token Bucket Rate Limiter Implementation

TokenBucketRateLimiter.java

package org.lobster1234.misc;


import java.util.concurrent.*;
import java.util.function.Consumer;

/**
 * Implementation of a token bucket rate limiter.
 */
public class TokenBucketRateLimiter {

    //Need to figure out if any other data structure is better here
    //Stack<Integer> tokens = new Stack<>();
    int tokens;

    /**
     *
     * @param numTokens The number of tokens allowed
     * @param time The timeframe for the above
     */
    public TokenBucketRateLimiter(int numTokens, TimeUnit time){
        //lets create our bucket and initialize it
        tokens = numTokens;
        //lets create a thread that will keep filling the bucket, which we can just use an array for
        Runnable bucketFiller = ()-> tokens = numTokens;

        //now we schedule this runnable to execute every TimeUnit
        ScheduledExecutorService service = Executors.newScheduledThreadPool(1);
        service.scheduleAtFixedRate(bucketFiller,0,1,time);
    }

    /**
     *
     * @param request The payload
     * @param success The function to call with success
     * @param failure The function to call for failure (throttle)
     */
    public void execute(RequestPayLoad request,  Consumer<RequestPayLoad> success, Consumer<RequestPayLoad> failure){
        if(tokens<=0){
            System.out.println("Throttled, no tokens in the bucket");
            failure.accept(request);
        }else{
            --tokens;
            System.out.println("Removing token, new size is " + tokens);
            success.accept(request);
        }
    }

}

class RequestPayLoad{
    String payload;
    public RequestPayLoad(String string){
        this.payload = string;
    }

    public String getPayload(){
        return payload;
    }
}