Convert an enum to integer

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11 Replies - 29628 Views - Last Post: 14 February 2010 - 06:10 PM Rate Topic: -----

#1 Guest_Johan Groth*


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Convert an enum to integer

Posted 12 February 2010 - 10:02 AM

Hi all,
suppose you got an enum defined like this:
enum ServerErrorCodes {
  OK(100), NotFound(404);

  private final int id;
  ServerErrorCodes(int id) {
     this.id = id;
  }
}

Then suppose you get back an error code from a server as an integer, how do I convert that integer to enum ServerErrorCodes. I would like to write something like:
int result = getServerService("document");// dummy code just for this example
ServerErrorCodes serverResult = result; // this does not work. What magic is required, though?
switch (serverResult) {
  case OK:
     return true;
  case NotFound:
     return false;
}


Does anyone here know how to do it?

Regards,
Johan

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Replies To: Convert an enum to integer

#2 SwiftStriker00  Icon User is offline

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Re: Convert an enum to integer

Posted 12 February 2010 - 10:21 AM

You should be able to just cast out the value
int i = (int)ServerErrorCodes.NotFound;

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#3 n8wxs  Icon User is offline

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Re: Convert an enum to integer

Posted 12 February 2010 - 10:59 AM

Have a look at Java Programming - int to Enum
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#4 g00se  Icon User is offline

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Re: Convert an enum to integer

Posted 12 February 2010 - 11:14 AM

You'd only need to do

return serverResult.getId();


, having given it that method
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#5 SwiftStriker00  Icon User is offline

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Re: Convert an enum to integer

Posted 12 February 2010 - 11:38 AM

thanks for correcting me, too much C#
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#6 Guest_Johan Groth*


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Re: Convert an enum to integer

Posted 12 February 2010 - 02:05 PM

God, the subject is wrong! :stupid:
I meant I want to convert an integer to an Enum. If you look at the code (which thankfully describes what I want) that is what I'm trying to do.

So the question again. Does anyone here know how to do that?

Regards,
Johan
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#7 g00se  Icon User is offline

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Re: Convert an enum to integer

Posted 12 February 2010 - 02:14 PM

Quote

I meant I want to convert an integer to an Enum


In the technical sense of 'convert' that's not possible
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#8 jgroth  Icon User is offline

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Re: Convert an enum to integer

Posted 12 February 2010 - 02:29 PM

Ok, so the only way to do it is to implement a method that does it like:

ServerErrorCodes getEnum(int i) {
  switch (i) {
    case 100:
      return OK;
    case 404:
      return NotFound;
  }
}


Am I correct in this?

Regards,
Johan
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#9 g00se  Icon User is offline

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Re: Convert an enum to integer

Posted 12 February 2010 - 03:17 PM

You could do

    public ServerErrorCodes fromInt(int i) {
	return i == id? this : null;
    }

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#10 jgroth  Icon User is offline

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Re: Convert an enum to integer

Posted 14 February 2010 - 08:30 AM

So much more elegant than my solution. :)
Thank you very much.

Regards,
jgroth
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#11 horace  Icon User is offline

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Re: Convert an enum to integer

Posted 14 February 2010 - 09:29 AM

View Postjgroth, on 12 February 2010 - 08:29 PM, said:

Ok, so the only way to do it is to implement a method that does it like:

ServerErrorCodes getEnum(int i) {
  switch (i) {
    case 100:
      return OK;
    case 404:
      return NotFound;
  }
}


Am I correct in this?

Regards,
Johan

why not do something like
public final int OK=100, NotFound=404;

then use the values
switch (serverResult) {
  case OK:
     return true;
  case NotFound:
     return false;
 }

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#12 pbl  Icon User is offline

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Re: Convert an enum to integer

Posted 14 February 2010 - 06:10 PM

if you have to convert an enum into an int it is because your design has a flaw
review your architecture
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