Re: Reading from stdout

From:
=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 12 Sep 2013 20:32:03 -0400
Message-ID:
<52325d04$0$295$14726298@news.sunsite.dk>
On 9/12/2013 12:59 PM, White Spirit wrote:

I'm writing a unit test for a logger class that writes to stdout. The
logger class uses an OutputStreamWriter to wrap FileDescriptor.out:

   mOut = new OutputStreamWriter(new
FileOutputStream(FileDescriptor.out), "UTF-8");

My unit test instantiates the logger class as a local object. When I
try to read from FileDescriptor.out in my unit test class, however,
nothing is received:

  BufferedReader reader = new BufferedReader( new InputStreamReader( new
FileInputStream( FileDescriptor.out ) ) );
  // do some logging
  // ...
  String n = reader.readLine();

Is there any way of reading what the logger is outputting?


If that logger class had been well behaving and used System.out
as the documentation recommends, then it would be easy to do
with System.out, but this way it is more tricky because
FileDescriptor.out refers directly to some native OS ref.

The best thing would be to change that logger class to use
System.out.

If not then I think you would need to dive deep into some
JNI and native calls.

Arne

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