Hi Ceki,
the only thing that I don't understand is why Appender requires a
layout at all.
It would by cleaner if there was a sub-interface, e.g.
LayoutAwareAooender (just a spontaneous suggestion), that extended
Appender and would add said methods.
Some appenders, like SocketAppender or some fictitious appender that
would simply serialize the events to a file (I'm planning to implement
such an appender, btw), just don't need a layout at all.
AppenderBase would then just implement the basic Appender interface,
leaving the layout implementation to appenders that would really
require it.
This topic is covered by both http://jira.qos.ch/browse/LBCORE-1 and
http://jira.qos.ch/browse/LBCORE-56
Regards,
Joern.
On 09.02.2009, at 19:50, Ceki Gulcu wrote:
Hello all,
While working on chapter 11, migration of log4j appenders to
logback-classic, it occured to me that the current way AppenderBase
implements its layout setter and getter can be confusing. Here is the
relevant code:
abstract public class AppenderBase<E> extends ContextAwareBase
implements
Appender<E> {
public Layout<E> getLayout() {
return null;
}
public void setLayout(Layout<E> layout) {
}
// omitted code
}
The fact that the setLayout does nothing and getLayout always returns
null is somethat unexpected and may suprise users. This has apparently
already happended to Thilo Tanner as reported in LBCORE-56. See also
http://jira.qos.ch/browse/LBCORE-56
I'd like to change AppenderBase to:
abstract public class AppenderBase<E> extends ContextAwareBase
implements
Appender<E> {
Layout<E> layout;
public Layout<E> getLayout() {
return layout;
}
public void setLayout(Layout<E> layout) {
this.layout = layout;
}
// omitted code
}
The new code offers a reasonable default implementation for layout
getter and setter methods. It should decrease the aforementioned
surprise factor without causing harm to many appender implementations
which do not need a layout.
Comments?
--
Ceki Gülcü
Logback: The reliable, generic, fast and flexible logging framework
for Java.
http://logback.qos.ch
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