import java.math.BigInteger;

/**
 *  Worker class used in multithreading to check, whether a given number is a prime.
 */
public class Worker extends Thread {
    private boolean isPrime;
    private BigInteger minVal;
    private BigInteger maxVal;
    private BigInteger candidate;
    private boolean finished = false;
    private String threadName ;

    public Worker(BigInteger candidate, BigInteger min, BigInteger max, String threadName) {
        this.minVal = min;
        this.maxVal = max;
        this.candidate = candidate;
        this.isPrime = true;
        this.threadName = threadName;
        //System.out.println("Created "+threadName+" for "+min+"-"+max+"");
    }

    /**
     * Returns a flag, indicating whether the prime candidate has a divisor in the given interval.
     * Since the thread might be still be running, it is important to check it first by using the
     * hasFinished() method.
     *
     * @return flag indicating whether there is a divisor or not
     */
    public boolean isPrime() {
        return this.isPrime;
    }

    /**
     * Returns if the thread has finished checking the given interval.
     *
     * @return the boolean
     */
    public boolean hasFinished() { return this.finished; }

    public void run() {
        BigInteger divCandidate = minVal;
        if (divCandidate.mod(BigInteger.valueOf(2)).equals(BigInteger.ZERO)){
            divCandidate = divCandidate.add(BigInteger.ONE);
        }
        while (divCandidate.compareTo(maxVal) < 1){ //divCandidate <= maxVal
            //System.out.println(this.threadName + " is testing "+divCandidate);
            if (candidate.mod(divCandidate).equals(BigInteger.ZERO)) {
                this.isPrime = false;
                this.finished = true;
                return;
            }
            divCandidate = divCandidate.add(BigInteger.ONE).add(BigInteger.ONE);
        }
        this.finished = true;
        // No divisor found, we are done for this interval
    }
}