if ( ( n_terminal == null ) || ( c_terminal == null ) ) {
throw new IllegalArgumentException( "attempt to create binary domain combination using null" );
}
- _id_0 = n_terminal;
- _id_1 = c_terminal;
+ _id_0 = n_terminal.getId();
+ _id_1 = c_terminal.getId();
}
public DirectedBinaryDomainCombination( final String n_terminal, final String c_terminal ) {