package net.jcip.examples;

import java.math.BigInteger;

import java.util.*;

import net.jcip.annotations.*;

/**

* OneValueCache

* <p/>

* Immutable holder for caching a number and its factors

*

* @author Brian Goetz and Tim Peierls

*/

@Immutable

public class OneValueCache {

private final BigInteger lastNumber;

private final BigInteger[] lastFactors;

public OneValueCache(BigInteger i,

BigInteger[] factors) {

lastNumber = i;

lastFactors = Arrays.copyOf(factors, factors.length);

}

public BigInteger[] getFactors(BigInteger i) {

if (lastNumber == null || !lastNumber.equals(i))

return null;

else

return Arrays.copyOf(lastFactors, lastFactors.length);

}

}