question: public void doneWithParameters ( ) { if ( info . parameterCount == VAR_ARGS ) { int len = varArgs . size ( ) ; checkParameterCount ( len ) ; args = new Expression [ len ] ; varArgs . toArray ( args ) ; varArgs = null ; } else { int len = args . length ; if ( len > 0 && args [ len - 1 ] == null ) { throw DbException . get ( ErrorCode . INVALID_PARAMETER_COUNT_2 , info . name , "" + len ) ; } } }
target:  This method is called after all the parameters have been set. It checks if the parameter count is correct.