reading bytes with BufferedReader?

[R]

Hi All,

I have a simple client - server application (using sockets).
80% responses of server are plain text messages,
20% are mixed: they are text messages with binary attachments.

The structure is very simple. If message is plain text the last line
contains "END OF TRANSMISSION".
If message has attachment (only 1 possible) it contains: BINATY
ATTACHMENT: {SIZE IN BYTES}

I'm reading messages with BufferedReader.

BufferedReader can not read bytes. It has read() method but it reads
ints - futher more
it reads int in big-endian order (the transmission is little-endian).

I pass socket.getInputStream() into constructor of my reading thread:

public InputThread(InputStream in) {
this.raw = in;
this.in = new BufferedReader(new InputStreamReader(in));
}

the beggining of the message is read with the BufferedReader,
then (if attachment is present) I use the raw object (InputStream),
it has read(byte[] buffer) method but when I use it it returns -1.
System.out.println(raw.read(bytes));

Can streams be mixed? E.g. I read some text with BufferedReader and
then I'll read some bytes
with orginal InputStream?

 

[bharat_sharma_5005]

Hi All,

I have a simple client - server application (using sockets).
80% responses of server are plain text messages,
20% are mixed: they are text messages with binary attachments.

The structure is very simple. If message is plain text the last line
contains "END OF TRANSMISSION".
If message has attachment (only 1 possible) it contains: BINATY
ATTACHMENT: {SIZE IN BYTES}

I'm reading messages with BufferedReader.

BufferedReader can not read bytes. It has read() method but it reads
ints - futher more
it reads int in big-endian order (the transmission is little-endian).

I pass socket.getInputStream() into constructor of my reading thread:

public InputThread(InputStream in) {
this.raw = in;
this.in = new BufferedReader(new InputStreamReader(in));

}the beggining of the message is read with the BufferedReader,
then (if attachment is present) I use the raw object (InputStream),
it has read(byte[] buffer) method but when I use it it returns -1.
System.out.println(raw.read(bytes));

Can streams be mixed? E.g. I read some text with BufferedReader and
then I'll read some bytes
with orginal InputStream?

 

[Tom Forsmo]

Hi All,

I have a simple client - server application (using sockets).
80% responses of server are plain text messages,
20% are mixed: they are text messages with binary attachments.

The structure is very simple. If message is plain text the last line
contains "END OF TRANSMISSION".
If message has attachment (only 1 possible) it contains: BINATY
ATTACHMENT: {SIZE IN BYTES}

I'm reading messages with BufferedReader.

BufferedReader can not read bytes. It has read() method but it reads
ints - futher more
it reads int in big-endian order (the transmission is little-endian).

First of all you should always stick to the internet standard of network
byte order, which is big endian. Second of all write the size in text
instead of as bytes, the same goes with the binary data format it using
Base64 coding or something similar. The you can read and process
everything as text and then convert to byte,integer, float etc, what you
need to convert.

Basically, stick to one format or the other, i.e. binary or text. It
doesn't complicate things as much and it will be easier to extend the
design of the protocol.

I pass socket.getInputStream() into constructor of my reading thread:

public InputThread(InputStream in) {
this.raw = in;
this.in = new BufferedReader(new InputStreamReader(in));
}

the beggining of the message is read with the BufferedReader,
then (if attachment is present) I use the raw object (InputStream),
it has read(byte[] buffer) method but when I use it it returns -1.
System.out.println(raw.read(bytes));

Can streams be mixed? E.g. I read some text with BufferedReader and
then I'll read some bytes
with orginal InputStream?

you should never mix streams. It makes the code unmanageable and the
functionality untrustworthy. Unless you are chaining them, as you have
done with the this.in stream. And yes it is technically possible to open
several readers and manipulate them independently, but as said its not
advisable.

An example is using a PushbackReader and when you find any bytes, you
push it back and open a new InputStream from the pushback stream and
read the raw bytes. But then you are going to have problems the next
time you read from the BufferedReader, because the mark of the stream is
at different places depending on whether you are using the inputstream
stream or the BufferedReader stream.

So as stated it is better to choose either complete binary or text protocol.

tom

 

[EJP]

An example is using a PushbackReader and when you find any bytes, you
push it back and open a new InputStream from the pushback stream

Well you can't even do that for a start, you can't put an InputStream on
top of a Reader.

In the OP's circumstance I would just use the dreaded
DataInputStream.readLine() to read the lines and DataInputStream.read()
to read the bytes.

 

[Tom Forsmo]

Well you can't even do that for a start, you can't put an InputStream on
top of a Reader.

No, but you can use the InputStream the Reader is based. Ok, its not
opening up a new InputStream, but you are still using the underlying
stream directly.

tom

 

[EJP]

No, but you can use the InputStream the Reader is based. Ok, its not
opening up a new InputStream, but you are still using the underlying
stream directly.

.... but you still won't get any of the data pushed back into the
PushbackInputStream!

 

[EJP]

No, but you can use the InputStream the Reader is based. Ok, its not
opening up a new InputStream, but you are still using the underlying
stream directly.

.... but you still won't get any data pushed back into the PushbackReader!

 

[Tom Forsmo]

.... but you still won't get any data pushed back into the PushbackReader!

I went back to the paragraph in the book I thought I read this, but I
must have misread it. I apologise for the confusion on that claim.

tom

 

[Tom Forsmo]

.... but you still won't get any data pushed back into the PushbackReader!

I went back to the paragraph in the book I thought I read this, but I
must have misread it. I apologise for the confusion on that claim.

What you can do, though, is to use a PushbackInputStream. Your read some
bytes, give it to a reader which parses it, when the reader reaches the
binary data, it returns with a value stating how many bytes where
consumed by the reader. What was not consumed is pushed back into the
stream and you open up e.g. a DataInputStream to read the binary data.
When the DataInputStream is finished you could potentially return and
give control to the reader again, this way going back and forth between
text and binary. Its a bit complicated and not as clean. It would be
easier and cleaner to just use a complete binary or text based protocol
instead.

tom