/// <summary>
/// Finds the currency pair that is a cross between this pair and the other pair.
/// <para>
/// The cross is only returned if the two pairs contains three currencies in total,
/// such as AAA/BBB and BBB/CCC and neither pair is an identity such as AAA/AAA.
/// <ul>
/// <li>Given two pairs AAA/BBB and BBB/CCC the result will be AAA/CCC or CCC/AAA as per the market convention.
/// <li>Given two pairs AAA/BBB and CCC/DDD the result will be empty.
/// <li>Given two pairs AAA/AAA and AAA/BBB the result will be empty.
/// <li>Given two pairs AAA/BBB and AAA/BBB the result will be empty.
/// <li>Given two pairs AAA/AAA and AAA/AAA the result will be empty.
/// </ul>
///
/// </para>
/// </summary>
/// <param name="other"> the other currency pair </param>
/// <returns> the cross currency pair, or empty if no cross currency pair can be created </returns>
public Optional <CurrencyPair> cross(CurrencyPair other)
{
ArgChecker.notNull(other, "other");
if (Identity || other.Identity || this.Equals(other) || this.Equals(other.inverse()))
{
return(null);
}
// AAA/BBB cross BBB/CCC
if (counter.Equals(other.@base))
{
return(of(@base, other.counter).toConventional());
}
// AAA/BBB cross CCC/BBB
if (counter.Equals(other.counter))
{
return(of(@base, other.@base).toConventional());
}
// BBB/AAA cross BBB/CCC
if (@base.Equals(other.@base))
{
return(of(counter, other.counter).toConventional());
}
// BBB/AAA cross CCC/BBB
if (@base.Equals(other.counter))
{
return(of(counter, other.@base).toConventional());
}
return(null);
}
public virtual void test_inverse_same()
{
CurrencyPair test = CurrencyPair.of(GBP, GBP);
assertEquals(test.inverse(), CurrencyPair.of(GBP, GBP));
}