Maths Puzzle: The self descriptive number

SelfRef.java

import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Supplier;
import java.util.stream.Stream;

/*

Maths Puzzle: The self descriptive number

https://www.youtube.com/watch?v=K6Qc4oK_HqY

4: 1210
4: 2020
5: 21200
7: 3211000
8: 42101000
9: 521001000
10: 6210001000

*/
public class SelfRef {
	public static class Ints implements Supplier<Integer> {
		private final AtomicInteger CURRENT = new AtomicInteger();

		private Ints(int start) {
			CURRENT.set(start);
		}

		@Override
		public Integer get() {
			return CURRENT.getAndIncrement();
		}
	}

	public static class Longs implements Supplier<Long> {
		private final AtomicLong CURRENT = new AtomicLong();

		@Override
		public Long get() {
			return CURRENT.getAndIncrement();
		}
	}

	private static final long[] POW = new long[11];

	static {
		for (int i = 0; i <= 10; i++) {
			POW[i] = (long) Math.pow(10, i);
		}
	}

	public static void main(String... args) {
		for (int numDigits = 1; numDigits <= 10; numDigits++) {
			int myNumDigits = numDigits;
			long max = tenPow(myNumDigits) - 1L;
			Stream.generate(new Longs()).parallel()
				.limit(max)
				.filter(number -> isValidNumber(number, myNumDigits))
				.forEach(number -> print(myNumDigits, number));
		}
	}

	private static synchronized void print(int numDigits, long number) {
		System.out.printf("%d: %d", numDigits, number).println();
	}

	private static boolean isValidNumber(long number, int numDigits) {
		if (crossSum(number, numDigits) != numDigits) {
			return false;
		}

		for (int idx = 0; idx < numDigits; idx++) {
			if (count(number, idx, numDigits) != getDigit(number, idx, numDigits)) {
				return false;
			}
		}
		return true;
	}

	private static int crossSum(long number, int numDigits) {
		int result = 0;
		for (int idx = 0; idx < numDigits; idx++) {
			result += getDigit(number, idx, numDigits);
		}
		return result;
	}

	private static int count(long number, int searchFor, int numDigits) {
		int result = 0;
		for (int idx = 0; idx < numDigits; idx++) {
			if (getDigit(number, idx, numDigits) == searchFor) {
				result++;
			}
		}
		return result;
	}

	private static int getDigit(long number, int digitIndex, int numDigits) {
		return (int) ((number / tenPow(numDigits - 1 - digitIndex)) % 10);
	}

	private static long tenPow(int x) {
		return POW[x];
	}
}