[brailleblaster] Re: byte arrays versus strings
- From: "qubit" <lauraeaves@xxxxxxxxx>
- To: <brailleblaster@xxxxxxxxxxxxx>
- Date: Fri, 10 Dec 2010 13:37:38 -0600
Thanks Chris -- that's good to know.
I'll save this for future reference.
I'm going back to the online class docs and perhaps I'll find what I need.
--le
----- Original Message -----
From: "Chris von See" <chris@xxxxxxxxxxxxx>
To: <brailleblaster@xxxxxxxxxxxxx>
Sent: Friday, December 10, 2010 1:17 PM
Subject: [brailleblaster] Re: byte arrays versus strings
Maybe I'm not understanding your question...
Any classes derived from java.io.InputStream and java.io.OutputStream
are by definition byte-oriented streams:
http://download.oracle.com/javase/tutorial/essential/io/bytestreams.html
so if you are using the objects returned from Process.getInputStream()
and Process.getOutputStream() you are required to write bytes, not
Java characters, to the stream.
Character streams, by contrast, are derived from java.io.Reader and
java.io.Writer:
http://download.oracle.com/javase/tutorial/essential/io/charstreams.html
and allow you to read and write Java characters and String objects.
You can convert a character-oriented reader/writer to a byte-oriented
stream using java.io.InputStreamReader and java.io.OutputStreamWriter,
which allow you to specify the encoding of the byte stream to be
written. Any characters read from or written to those classes are
automatically converted from/to bytes using the encoding you specify,
or the default encoding if you don't specify one.
Cheers
Chris
On Dec 10, 2010, at 10:20 AM, John J. Boyer wrote:
> Laura,
>
> I am no exxpert, but I think the input, output and error streems
> should
> be character streams. This will handle most stuff and will be easily
> usable by Java. Graphics would have to be handled differently, but I
> think we should wait until we have a need to handle them with C
> libraries. They will require separate clases.
>
> I haven't looked much at the Process class, though I have looked at
> Runtime to find out how to call file2brl in a subcommand. I'm afraid
> we
> will be learning together.
>
> John
>
> On Fri, Dec 10, 2010 at 11:54:04AM -0600, qubit wrote:
>> JohnB --
>> I understand what you are saying -- but there's still a sticking
>> point.
>> The input, output, and error streams are declared as InputStream and
>> OutputStream's, which are general streams that could take either
>> byte arrays
>> (for binary or general data) or character streams, which I
>> understand can be
>> put in a String class. I am unsure what exactly the
>> getInputStream(),
>> getOutputStream() and getErrorStream() are returning as there are
>> subclasses
>> to class InputStream and OutputStream that cater to both kinds of
>> data. I
>> am wondering if there is a way to query the type of subclass of a
>> class of
>> an object. That would solve it.
>> Anyway, There might be uses of my class that want to do some kind of
>> operation on a general data file. For example, is there ever a
>> graphic or
>> other binary data embedded in what I would be sending through the
>> program
>> that would be spit back out on the output stream?
>>
>> This is just a matter of understanding java from the ters online
>> docs. I
>> could resort to one of the books I guess. But I think the online
>> docs
>> should be enough.
>> --le
>>
>>
>>
>>
>>
>>
>> ----- Original Message -----
>> From: "John J. Boyer" <john.boyer@xxxxxxxxxxxxxxxxx>
>> To: <brailleblaster@xxxxxxxxxxxxx>
>> Sent: Friday, December 10, 2010 1:29 AM
>> Subject: [brailleblaster] Re: byte arrays versus strings
>>
>>
>> Laura,
>>
>> As I see it, your code should be written for generality, so it can be
>> used to calll other command-line filters. The input and output
>> streams
>> should therefore be strings.
>>
>> Another part of your code might take a stream containing a MathML
>> fragment and convert it to a JDOM subtree. This code might be
>> useful in
>> other parts of BrailleBlaster, so it should also be generalized.
>>
>> Hope this helps,
>> John B.
>>
>> On Thu, Dec 09, 2010 at 07:25:06PM -0600, qubit wrote:
>>> Ok, this is where I need JohnB's expertise with characters and byte
>>> strings.
>>> Of course, anyone else can chime in too.
>>>
>>> I have a buffered stream going from brailleblaster to the input of
>>> process
>>> just spawned, and 2 streams coming back for standard error and
>>> standard
>>> out.
>>>
>>> I will be managing the pipes in a class constructor / finalizer.
>>> My question is, in the docs for the input and output streams in
>>> java.io,
>>> there are subclasses that manage byte arrays and subclasses that
>>> do just
>>> character strings.
>>> My class will provide you with a read and a write method. Should
>>> I just
>>> assume that everything that goes over the pipe is a character
>>> stream, or
>>> are
>>> there cases where I can't assume that?
>>>
>>> Should this be a character stream or a byte stream?
>>> Should I use threads that handle the input and output on these
>>> streams?
>>>
>>> I am trying to get all my "ducks in a row" as a family member
>>> likes to
>>> say.
>>> Any comments are welcome.
>>> --le
>>>
>>
>> --
>> John J. Boyer; President, Chief Software Developer
>> Abilitiessoft, Inc.
>> http://www.abilitiessoft.com
>> Madison, Wisconsin USA
>> Developing software for people with disabilities
>>
>>
>
> --
> John J. Boyer; President, Chief Software Developer
> Abilitiessoft, Inc.
> http://www.abilitiessoft.com
> Madison, Wisconsin USA
> Developing software for people with disabilities
>
>
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