Partial redirection of System.out

[ceki]

Hello,

I am trying to use sysout-over-slf4j in order to redirect SOAP messages printed by the com.sun.xml.ws.transport.http.client.HttpTransportPipe class on System.out. This class directly invokes the System.out.println(String) method which is redirected just fine. However, HttpTransportPipe also invokes the Ssytem.out.write((byte b[], int off, int len) method which unfortunately is not redirected. It turns out that data I am actually interested in is output in that invocation. Anyway, looking at the SLF4JPrintStreamImpl class the culprit seems to be:

264 @OverRide
265 public void write(final byte[] buf, final int off, final int len) {
266 originalPrintStream.write(buf, off, len);
267 }

For some reason, this method seems to invoke the original stream instead of redirecting to SLF4J. Could you please shed some light on the matter?

See also: http://projects.lidalia.org.uk/sysout-over-slf4j/xref/uk/org/lidalia/sysoutslf4j/system/SLF4JPrintStreamImpl.html#266

[Mahoney]

Hi Ceki,

The write methods on SLF4JPrintStreamImpl deliberately write to the original System output in order to allow Logback, Log4J and JULI to append to the console without any additional performance impact, since they all use the write methods to do so.

As the problem I was trying to solve was basically naive System.out.println statements used for logging, this seemed to me the best compromise I could make, as otherwise logging to the console via a logging subsystem would be prohibitively expensive (it would require generating a stack trace and examining the stack to see if the call came from a logging subsystem or not on every single write to the console).

At the moment I can't think of a way to meet this use case without damaging performance in a way I suspect would be prohibitive.

[Mahoney]

Further note - I've got a fix for this in version 2, which I'll release when I've finished documenting it.