qpid-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Martin Ritchie <martin.a.ritc...@jpmorgan.com>
Subject Re: Bug: BytesMessage.reset() throws MessageNotWriteableException
Date Wed, 06 Sep 2006 13:35:20 GMT
I've had a look at the rest code and I would suggest the checkWritable(); 
is not required. Removing this as below would prevent the exception from 

The problem is I don't understand the difference in mina between flip() 
and rewind().

from the mina spec.

flip() makes a buffer ready for a new sequence of channel-write or 
relative get operations: It sets the limit to the current position and 
then sets the position to zero.
rewind() makes a buffer ready for re-reading the data that it already 
contains: It leaves the limit unchanged and sets the position to zero. 

I seems to me that rewind() would be what we want for a JMS reset() [Puts 
the message body in read-only mode and repositions the stream of bytes to 
the beginning. ]

However the BytesMessageTest fails when using rewind() as the size of the 
read bytes is not known. Which suggests that the code uses the limit value 
in the mina buffer to determine the size of the ByteMessage and as it 
isn't set with a rewind() it returns the size of the Mina buffer (1024).

I'm sure flip() is correct and all that need be done is remove the 
checkWritable() call. It would be good if someone (I guess Robert or 
Gordon) more familiar with this bit of code could OK this change.

   public void reset() throws JMSException
        _readable = true;



"Colin Crist" <colincrist@messageforge.org>
2006-09-05 17:36
Please respond to qpid-dev
        To:     <qpid-dev@incubator.apache.org>
        Subject:        Bug: BytesMessage.reset() throws 

BytesMessage.reset() can be called on a read only message, its purpose
is to "reset" the message so it can be read again from the start, it
does not affect the message content.
2006-09-05 17:25:34,436 [AWT-EventQueue-0] ERROR
hermes.renderers.HexMessageRenderer - exception converting message to
javax.jms.MessageNotWriteableException: You need to call clearBody() to
make the message writable

This communication is for informational purposes only. It is not intended as an offer or solicitation
for the purchase or sale of any financial instrument or as an official confirmation of any
transaction. All market prices, data and other information are not warranted as to completeness
or accuracy and are subject to change without notice. Any comments or statements made herein
do not necessarily reflect those of JPMorgan Chase & Co., its subsidiaries and affiliates.

This transmission may contain information that is privileged, confidential, legally privileged,
and/or exempt from disclosure under applicable law. If you are not the intended recipient,
you are hereby notified that any disclosure, copying, distribution, or use of the information
contained herein (including any reliance thereon) is STRICTLY PROHIBITED. Although this transmission
and any attachments are believed to be free of any virus or other defect that might affect
any computer system into which it is received and opened, it is the responsibility of the
recipient to ensure that it is virus free and no responsibility is accepted by JPMorgan Chase
& Co., its subsidiaries and affiliates, as applicable, for any loss or damage arising
in any way from its use. If you received this transmission in error, please immediately contact
the sender and destroy the material in its entirety, whether in electronic or hard copy format.
Thank you.

View raw message