Robert Klemme schrieb:
Still, why do you want to do this? What problem are you trying to
solve? I'm not convinced that it is a good idea - especially when using
unbounded buffers.
A pipe is not a memory stream. In a pipe the reader
does read where the writer does write. But I don't
have this requirement.
The only requirement I have, is that I can use
the memory streams in place of >>TEMPORARY FILES<<.
Whereas >>TEMPORARY FILES<< have a name and usually
exist on some media.
The memory streams should not exist on some media,
except in the memory. But they should share with
TEMPORARY FILES<< multiple readers / writers and
positioninng. Since I can use a >>TEMPORARY FILES<<
name and open a RandomAccessFile with it.
So basically in my application I would like to have
some class, call it MemoryStream. And It would like
to be able to instantiate it. And this instance serves
than as a kind of a file name.
So this instance I should be able to use where I normally
would use the >>TEMPORARY FILES<< name. The only places
that come to my mind are:
- creating an input stream from a file name, should
then work from a memory stream instance.
- creating an output stream from a file name, should
then work from a memory stream instance.
- creating a random acccess file from a file name,
should then work from a memory stream instance.
What the memory stream instance will have in common
with a >>TEMPORARY FILES<< name, is that it will go
away when the application closes. So they are very
similar to >>TEMPORARY FILES<< with the option delete
on close.
Also I would like to be able to use the same memory stream
to open input streams, output streams, random access files,
as many as I want. This is also provided by >>TEMPORARY
FiLES<<, once a >>TEMPORARY FILES<< name is established, it
can be used for all kinds of stuff.
Here is a little example:
A large clip board: This could be realized by a temporary
file. When you make the copy operation, you simply write
the copied content into the temporary file. When you make
the past operation you reopen the temporary file and
read the content that should be pasted from it.
The above could be realized by even passing the >>TEMPORARY
FILES<< name around in the system clipboard, so that the copy
paste works across applications. Provided that the applications
understand the content type.
But memory streams cannot passed around like this. Here is
the difference to >>TEMPORARY FILES<<. In their simple
implementation they are confined to the application that
created them.
Of course we could extend them and provide some RMI extension
of them, or what ever, so that the a memory stream references
becomes mobile. Or we could implement them in special shared
memory of the operating system, so that a direct shared access
from multiple applications is possible.
This mobility and shared access across multiple application,
which is a property of >>TEMPORARY FILES<<, is not required
for the memory streams I am looking for. So I guess if my
grandmother could program as she can knit pullovers for me,
she might do a memory stream class for me.
But unfortunately she knows only COBOL and I am looking for
a Java library. But she assured me that something like this
must exist on the web, and that I don't need to go into lengths
to code it by myself. So she told me:
It's not difficult, but why reinvent the wheel?
real problem you are trying to solve. Basically if you want to use
effort to modify byte code of classes. So your "memory stream" could be
made to work easily with your own code only. But then, you'd probably
sequences of bytes. If you need to store unstructured text, you can use
a StringBuffer. If you need to store other kinds of data you can use
create disk IO. For short lived temporary files chances are that you
delete the file before it got written to disk. And then there are in