null vs String.Empty

[Chris Maunder]

If you have a function that returns a string, and that function fails, do you prefer to return null or String.Empty? Vote 1 = null Vote 5 = String.Empty

cheers, Chris Maunder

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[Smith]

3. "failed" :-D

NULL

[DotNetInterest]

I would return null, since String.Empty could be a valid string for the "caller", but a null object is "typically" not and i would expect the caller to handle "null" value returned by a called funtion (good practice).

[Zac Howland]

I take it this is in Java? Or are you talking about just in general?

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week Zac

[Nemanja Trifunovic]

Chris Maunder wrote:

do you prefer to return null or String.Empty?

Neither. If a function "fails", I simply throw an exception.

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[Dario Solera]

I'd say it could be more correct to return String.Empty, but I use null. Actually I don't know what is "phisically" String.Empty, but I guess it's an instance. If you return a null, at least you save memory and therefore less GC calls are needed (especially because you're using strings). IMHO.

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[Chris Losinger]

C++ doesn't have String.Empty.

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[Graham Bradshaw]

Neither. I would never mix the return value and the success/fail. In MFC/C++, I'd do that as a function that returned a BOOL, indicating whether it worked or not, and a reference to a CString as a parameter.

[Dario Solera]

Nemanja Trifunovic wrote:

Neither. If a function "fails", I simply throw an exception.

It could be correct, if the method actually fails. A null indicates some "void" result, I guess, and not necessarily a failure or error. :)

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[Judah Gabriel Himango]

String.Empty is in the .NET framework

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[Nish Nishant]

Chris Losinger wrote:

C++ doesn't have String.Empty.

It does if you turn on /clr - and then you have String::Empty :rolleyes:

Regards, Nish

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[Zac Howland]

Chris Losinger wrote:

C++ doesn't have String.Empty.

Returning a string("") or CString("") would be almost equivalent to String.Empty.

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week Zac

[Douglas Troy]

Not sure it matters, since you can just use the following check:

if (!string.IsNullOrEmpty(MyReturnStringValue)) 
{ 
    ... 
}

But I generally return empty strings ...

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[Judah Gabriel Himango]

If the function truely failed, that's what exceptions are for. If the function has functioned properly (has not failed) but the there is no result, that's when you return null. Say you had a function like this: public string GetNodeTextAtIndex(int index) { ... } If the function fails for any reason (say, bad input, maybe specifying a negative number as the index), then you throw an exception. If the function otherwise succeeds, but doesn't find any node at that index, you return null.

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[Kevin McFarlane]

If the method actually fails then throwing an exception is appropriate. But if the method doesn't fail then returning String.Empty or null could be valid depending on the context. However, in general, I like to interpret null as either "not initialised" or indicative of an error. Ideally the source code should describe exactly what it means when it returns an empty string or or a null.

Kevin

[Colin Angus Mackay]

It depends. It may be valid to return an empty string, in which case you can't use it to signify a failure, in which case null is the best option.

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[Anish M]

May be null, but for sure not an Empty String

[led mike]

Chris Maunder wrote:

and that function fails

Based on the responses so far you need to define "fails". IMHO failure indicates an exceptional condition and therefore an exception should be thrown. However if you are referring to a valid outcome of an operation I would likely choose null over an empty string for two reasons: 1) it is more efficient 2) Since the caller must "check" the return value to determine the outcome, it is part of the contract and documented, and therefore is not significant in ways other than efficiency.

led mike

[Kevin McFarlane]

Good summary, Judah.:)

Kevin

[Nemanja Trifunovic]

Judah Himango wrote:

String.Empty is in the .NET framework

I know that. I usually don't criticize things I don't know :) [EDIT} So you answered to Chris L. not me. Another CP forum joke[/EDIT]

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