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A simple question?

Posted on 2004-09-22
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Last Modified: 2010-03-31
Hi Experts, I am a Java Newbie and am just about getting my head around Java Code. I have been looking at some source code available on the net and was wondering if someone could explain this (simply to me). first the code (or part of it(:

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import java.io.FileNotFoundException;
import java.io.IOException;

public class FileManager
{
  public FileManager() {  }
  public static void setFileTypeAndCreator(String s, long l, long ll) throws IOException {}
  public static void setFileType(String s, long l) throws IOException{}
  public static void setFileCreator(String s, long l) throws IOException{}
  public static long getFileTypes(String filename) throws IOException
  {
    return 0L;
  }
}

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The question is a simple one. What is the point of having a method for example that (if I understand this correctly), does nothing. For example the:

public static void setFileType(String s, long l) throws IOException{}

What does a method like this actually do? I keep seeing this sort of thing all over the place but I am puzzled as to what it is meant to achieve -- any help appreciated.


0
Comment
Question by:zaphod_beeblebrox
8 Comments
 
LVL 35

Expert Comment

by:girionis
ID: 12121781
>
> The question is a simple one. What is the point of having a method for
> example that (if I understand this correctly), does nothing. For example the:

> public static void setFileType(String s, long l) throws IOException{}

> What does a method like this actually do? I keep seeing this sort of
> thing all over the place but I am puzzled as to what it is meant to
> achieve -- any help appreciated.

Where did you get the code above? It is pointless to have it the way it is, you are right. However is you had an intereface where you need to implement you would need to provide implementations of the methods defined in the interface, even if they do nothing at all, so you coudl have somethign like the above.
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Accepted Solution

by:
CEHJ earned 75 total points
ID: 12121785
It's there so it can be overridden and implemented in a subclass or becuase it requires an implementation to fulfil an interface or abstract class
0
 
LVL 18

Expert Comment

by:armoghan
ID: 12121788
This class seems to be kind of Adaptor class which implements method with nothing in it.
When you extend from these classes you override these functions and provide implementation
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LVL 35

Expert Comment

by:girionis
ID: 12121793
Or maybe this is a generic class and the subclasses need to extend it, but again you do not extend any functionallity, so it's pointless I'd say.
0
 
LVL 35

Expert Comment

by:girionis
ID: 12121797
It would be better for the class to have been decalred abstract I reckon.
0
 

Author Comment

by:zaphod_beeblebrox
ID: 12121808
Hell guys, that was quick. I just wanted to know if the code made any sense as it was. I am awarding the points to CEHJ because his answers makes the most sense to me, but all your answers are good and much appreciated
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 12121818
>>It would be better for the class to have been decalred abstract I reckon.

Indeed. It's obviously been written by someone who doesn't understand interfaces/abstract classes
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 12121859
:-)
0

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