Which XXX completes the power function?

public class ExponentMethod $\{$

public static double raiseToPower$($double base, double exponent$)\{$

if $($exponent $!=0)\{$

XXX

else $\{$

return $(1/$base$)*$ raiseToPower$($base$,$ exponent$+1)$;

$\}$

$\}$

else $\{$

return $1$;

$\}$

$\}$

public static void main$($String args$[])\{$

int userBase;

int userExponent;

userBase $=2$;

userExponent $=4$;

System.out.println$($userBase $+"^"+$ userExponent $+"="$

$+$ raiseToPower$($userBase$,$ userExponent$))$;

$\}$

$\}$