constructor loading it's object from a file

[Murat Tasan]

i'd like to have a constructor that loads an object from disk and returns
it... kinda like:

class MyClass
{
MyClass(File f)
{
ObjectInputStre am s = new ObjectInputStre am(new
FileInputStream (f));
this = (MyClass)s.read Object();
}
}

now i know you cannot do this because this in the constructor is a final
variable...

is there trick that i don't know of that can do this?

p.s., before i get the typical responses... i already am using a static
factory method to accomplish the same thing... i'm just looking to make it
even easier to use my classes.

thanks for any help,

murat


--
Murat Tasan
mxt6@po.cwru.ed u
tasan@eecs.cwru .edu
murat.tasan@cwr u.edu

http://genomics.cwru.edu

[Raymond DeCampo]

Re: constructor loading it's object from a file

Murat Tasan wrote:[color=blue]
> i'd like to have a constructor that loads an object from disk and returns
> it... kinda like:
>
> class MyClass
> {
> MyClass(File f)
> {
> ObjectInputStre am s = new ObjectInputStre am(new
> FileInputStream (f));
> this = (MyClass)s.read Object();
> }
> }
>
> now i know you cannot do this because this in the constructor is a final
> variable...
>
> is there trick that i don't know of that can do this?
>
> p.s., before i get the typical responses... i already am using a static
> factory method to accomplish the same thing... i'm just looking to make it
> even easier to use my classes.
>[/color]

What makes a constructor "easier" than a static method?

If you really wanted to do this you could read in the object from the
file and then copy all of its instance variables. Sounds like too much
work and too error prone for my taste however.

Ray

P.S. Can't tell if you edited it for posting, but don't forget to close
your streams in a finally clause.

[Amey Samant]

Re: constructor loading it's object from a file

> class MyClass[color=blue]
> {
> MyClass(File f)
> {
> ObjectInputStre am s = new ObjectInputStre am(new
> FileInputStream (f));
> this = (MyClass)s.read Object();
> }
> }
>[/color]

how about instead of reading your object into this , read it in some
temporary local object variable & then perform member by member copy
into this
something of this sort

class MyClass
{
int x;
MyClass(File f)
{
MyClass temp;
ObjectInputStre am s = new ObjectInputStre am(new
FileInputStream (f));
temp= (MyClass)s.read Object();
this.x=temp.x; //member by member
copy for all members
}
}



hope this should help
regards
amey