Question

Questions 9 and 10 are based on the code fragment below: if ((currentYear % 4 0) && (currentYear 100 !-0)) 11 (current Year 400 0)) daysInMonth [0]-31; days InMonth [1)-29; daysInMonth [2] -31; daysInMonth [3]-30; days InMonth [4]-31; daysInMonth [5]-30; daysInMonth [6]-31; days InMonth [7]-31; daysInMonth [8] -30; daysInMonth [9] -31; days InMonth [10]-30; daysInMonth [11)-31; ) else daysInMonth [0]-31; days InMonth [1]-28 daysInMonth [2] -31; daysInMonth [3] -30; days InMonth [4] -31 daysInMonth [5] -30; daysInMonth [6] -31; days InMonth [7]-31; daysInMonth [8] -30; daysInMonth [9] -31; days InMonth [10]-30; daysInMonth [11 ]-31; Using various refactorings discussed in lectures, we may rewrite this code as follows: daysInMonth -getDaysInMonth (isLeapYear (currentYear) ) ; private boolean isLeapYear (int year) final int FOUR 4 final int CENTURY 100 final int QUAD CENTURY 400; return (year FOUR 0) (year CENTURY Y0) 11 - (year QUAD CENTURY - 0); private int [] getDays In Month (boolean leapYear) int days - (31,28,31 , 30, 31,30,31,31, 30, 31,30, 31); if (leapYear) days (1) 29 return days QUESTION 9 The refactorings used in the code transformation above were DecomposeConditional, ExtractMethod, ExtractClass DecomposeConditional, ExtractMethod, ExtractConstant DecomposeConditional, ExtractMethod, ExtractConstant, ExtractClass (a) (b) (c) (d) DecomposeConditional, ExtractMethod, ExtractClass, Extractinterface. None of the above. (e) QUESTION 10 Which of the following statement/s about the refactored code is/are true? (a) Method is LeapYear is an example of the Observer patterm. (b) The methods isLeapYear and getDays InMonth could reasonably be declared public staticto allow wider use The refactored code correctly sets the number of days in February based on whether the current year is a leap year, but leaves other months unchanged from their initial setting (d) Options (a) and (e). Options (b) and (c) (e) QUESTION 11 With respect to Java's collections framework, lists differ from arrays because: arrays are of a fixed size but lists can shrink and grow lists are a primitive type but arrays are a subtype of class Object. any array element can be indexed but lists can be accessed by their endpoints only (a) (b) (c) all the elements of an array must be of the same type, but list elements can all be of different types (d) (e) Options (a) and (d) QUESTION 12 Suppose that you are writing an application which requires standardised, high volume accesses to a back-end SQL database via the JDBC API. You may assume that the tasks involve a mix of simple queries -with variations in the query parameters- and a number of more complex DB operations. The best approach for these high-volume queries is most likely to involve: (a) use of the JDBC:ODBC bridge and carefully constructed groups of Statement objects. use of the JDBC:ODBC bridge, Statement objects and stored procedures a vendor-specific Java DB driver and carefully constructed groups of Statement objects (b) (c) (d) a vendor-specific Java DB driver and wide use of PreparedStatement objects. (e) a vendor-specific Java DB driver and use of PreparedStatements and stored procedures

Answer 1

9. b) DecomposeConditional, ExtractMethod, ExtraConstant

10. (b) and (c)

11. a) arrays are of fixed size but lists can grow and shrink

12. a) use of the JDBC:ODBC bridge and carefully constructed groups of statement objects.