Common interface for our primality tests.

PrimalityTest.java

import java.math.BigInteger;

/** A common interface for the primality tests we'll look at. */
public abstract class PrimalityTest {
    public abstract boolean isPrime(BigInteger n);
    
    public void timedPrimeTest(BigInteger n) {
        System.out.println("Running test: " + getClass().getName());
        System.out.println("n: " + n);
        long startTime = System.currentTimeMillis();
        
        System.out.println("Prime?: " + isPrime(n));
        
        long elapsedTime = System.currentTimeMillis() - startTime;
        System.out.println("Time taken: " + elapsedTime + " milliseconds.");
    }
}