question: protected void engineInit ( AlgorithmParameterSpec genParamSpec , SecureRandom random ) throws InvalidAlgorithmParameterException { if ( ! ( genParamSpec instanceof DHGenParameterSpec ) ) { throw new InvalidAlgorithmParameterException ( "Inappropriate parameter type" ) ; } DHGenParameterSpec dhParamSpec = ( DHGenParameterSpec ) genParamSpec ; primeSize = dhParamSpec . getPrimeSize ( ) ; try { checkKeySize ( primeSize ) ; } catch ( InvalidParameterException ipe ) { throw new InvalidAlgorithmParameterException ( ipe . getMessage ( ) ) ; } exponentSize = dhParamSpec . getExponentSize ( ) ; if ( exponentSize <= 0 ) { throw new InvalidAlgorithmParameterException ( "Exponent size must be greater than zero" ) ; } if ( exponentSize >= primeSize ) { throw new InvalidAlgorithmParameterException ( "Exponent size must be less than modulus size" ) ; } }
target:  Initializes this parameter generator with a set of parameter generation values, which specify the size of the prime modulus and the size of the random exponent, both in bits.