Change parameter of method

Question

Say I have a following function in java, may be not good example but just came in mind ;)

public StudentEntity updateStudent(StudentEntity studentEntity)
{
    studentEntity.setName(...);
    studentEntity.setAddress(...);
    return studentEntity;
}

Is above approach valid?

Can we store a studentEntity in separate variable and update and return it. For example

public StudentEntity updateStudent(StudentEntity studentEntity)
{
    StudentEntity _studentEntity = studentEntity;
    _studentEntity.setName(...);
    _studentEntity.setAddress(...);
    return _studentEntity;
}

Is this correct ? How mutator methods should be? Please make me correct if wrong!

Possible duplicate: http://stackoverflow.com/questions/17655639/bad-programming-practice-to-alter-passed-objects-in-java — Ben Green, Aug 01 '14 at 09:25

score 3 · Answer 1 · answered Aug 01 '14 at 09:23

3

There is no reason to write

   StudentEntity _studentEntity = studentEntity;

It's just redundant.

If you are just updating and return prefer first way. The second way creates unnecessary confusion while reading the code aswell.

answered Aug 01 '14 at 09:23

Suresh Atta

120,458
37
198
307

some thoughts on website confuses. Says do not use out parameters or do not change them. PMD or Sonar reports also says same? – Prashant Shilimkar Aug 01 '14 at 09:28
@PrashantShilimkar what do you mean by that. Sorry , Did'nt get you. – Suresh Atta Aug 01 '14 at 09:31
His method does return the same object as it receives as a parameter. In most cases this seems redundant. An updateXY method sounds like something that mutates the given object. So no need for a return value. This pattern more reminds me of methods acting on immutable objects like Strings where the return value is a new String object. – mdo Aug 01 '14 at 16:06

Change parameter of method

1 Answers1