Find prime numbers using Eratostene's Sieve

Eratostene.scala

/**
 * Eratostene Sieve algorithm
 */

package eratostene

/**
 * Find prime numbers using Eratostene Sieve
 * @param maxPrime Find primes to maxPrime
 * @example
 *
        val e = new Eratostene(100)
        println("Computing...")
        e.compute()
        println("Done.")

        for (prime <- e.primes()) {
            println("Prime => " + prime)
        }
 *
 */
class Eratostene(maxPrime: Int) {

    protected val maxVal = maxPrime
    protected val sieve = Array.fill[Int](maxPrime)(1)

    require(maxPrime > 1)

    sieve(0) = 0
    sieve(1) = 0

    def compute() {

        var currentPrime = this.nextPrime(0)
        var i = 0

        while (currentPrime * currentPrime < this.maxVal) {
            i = currentPrime * currentPrime
            while (i < this.maxVal) {
                this.sieve(i) = 0
                i += currentPrime
            }
            currentPrime = this.nextPrime(currentPrime)
        }

    }

    def primes() : IndexedSeq[Int] = {

        for (p <- 0 until this.maxPrime
             if (this.sieve(p) == 1))
                yield p


    }

    private def nextPrime(lastPrime: Int): Int = {

        var i = lastPrime
        var foundIt = false

        while ( i <= this.maxVal && !foundIt) {
            i += 1
            if (this.sieve(i) == 1) foundIt = true
        }

        return i

    }

}