There is no way to use a custom Priority when using the
PropertyConfigurator. Major bummer, I know, because that's certainly more
straightforward than DOMConfigurator to use. The format of the XML for
DOMConfigurator is easy (if you know XML), but it's a bit of a pain to have
to include the extra libraries.
Other than that, the code below should give you a good example of how to
address your other concerns:
/**
* Provides support for the {@link TraceablePriority.TRACE} priority.
*/
public class TraceableCategory extends Category {
private static final Factory factory = new Factory();
private static final String instanceFQCN =
TraceableCategory.class.getName();
public TraceableCategory(String name) {
super(name);
}
/**
* This method overrides {@link Category#getInstance(String)} by supplying
* its own factory type as a parameter.
*/
public static Category getInstance(String name) {
return Category.getInstance(name, factory);
}
/**
* This method overrides {@link Category#getInstance(String)} by supplying
* its own factory type as a parameter.
*/
public static Category getInstance(Class cls) {
return Category.getInstance(cls.getName(), factory);
}
/**
* Log a message object with the {@link TraceablePriority#TRACE TRACE}
* priority.<p>
*
* This method first checks if this category is <code>TRACE</code>
* enabled by comparing the priority of this category with the {@link
* TraceablePriority#TRACE TRACE} priority. If this category is
* <code>TRACE</code> enabled, then it converts the message object
* (passed as parameter) to a string by invoking the appropriate
* {@link ObjectRenderer}. It then proceeds to call all the
* registered appenders in this category and also higher in the
* hierarchy depending on the value of the additivity flag.
*
* @param message the message object to log.
*/
public void trace(String message) {
if (isTraceEnabled())
callAppenders(new LoggingEvent(instanceFQCN, this,
TraceablePriority.TRACE,
message, null));
}
/**
* Check whether this category is enabled for the <code>TRACE</code>
* priority.<p>
*
* This function is intended to lessen the computational cost of
* disabled log trace statements.<p>
*
* For some <code>cat</code> Category object, when you write,
* <pre>
* cat.trace("This is entry number: " + i );
* </pre>
*
* You incur the cost constructing the message, concatenatiion in
* this case, regardless of whether the message is logged or not.<p>
*
* If you are worried about speed, then you should write
* <pre>
* if(cat.isTraceEnabled()) {
* cat.trace("This is entry number: " + i );
* }
* </pre>
*
* This way you will not incur the cost of parameter construction
* if tracing is disabled for <code>cat</code>. On the other hand,
* if the <code>cat</code> is trace enabled, you will incur the cost
* of evaluating whether the category is trace enabled twice. Once
* in <code>isTraceEnabled</code> and once in the <code>trace</code>.
* This is an insignificant overhead since evaluating a category
* takes about 1% of the time it takes to actually log.
*
* @return boolean - <code>true</code> if this category is trace
* enabled, <code>false</code> otherwise.
*/
public boolean isTraceEnabled() {
return(disable >= TraceablePriority.TRACE_INT) ?
false :
TraceablePriority.TRACE.isGreaterOrEqual(this.getChainedPriority());
}
// Any sub-class of Category must also have its own implementation of
// CategoryFactory.
public static class Factory implements CategoryFactory {
public Factory() {
}
public Category makeNewCategoryInstance(String name) {
return new TraceableCategory(name);
}
}
}
/**
* This class introduces a new priority level called TRACE. TRACE has
* lower priority than DEBUG.
*/
public class TraceablePriority extends Priority {
public static final int TRACE_INT = 800;
// We assimilate TRACE to DEBUG on Syslog
private static final int SYSLOG_TRACE_INT = 7;
public static final TraceablePriority TRACE =
new TraceablePriority(TRACE_INT, "TRACE", SYSLOG_TRACE_INT);
protected TraceablePriority(int level, String strLevel, int syslogEquiv) {
super(level, strLevel, syslogEquiv);
}
public static Priority toPriority(String sArg) {
if (sArg == null)
return TraceablePriority.TRACE;
return (sArg.equalsIgnoreCase("TRACE")) ?
TraceablePriority.TRACE :
Priority.toPriority(sArg);
}
public static Priority toPriority(int i) throws IllegalArgumentException {
return (i == TRACE_INT) ?
TraceablePriority.TRACE :
Priority.toPriority(i);
}
}
Then you would have an entry like this in your log4j.xml file:
<!-- Note the class attributes! -->
<root class="TraceableCategory">
<priority value ="trace"
class="TraceablePriority"/>
<appender-ref ref="MAIN" />
</root>
There's no need for mucking around with Hierarchies. The package scope used
in Priority is a nuisance (I consider the use of package scope to be a
design flaw in general), but inheratance let me treat it as private data and
continue on.
-Jim Moore
-----Original Message-----
From: Geert Mergan [mailto:[EMAIL PROTECTED]]
Sent: Thursday, February 15, 2001 10:42 AM
To: [EMAIL PROTECTED]
Subject: adding custom priorities
Hello,
I suppose I'm not the only one's trying to define custom priorities (TRACE,
ALWAYS, DEBUG2). It seems this is not as easy as I hoped it would be.
I've started with writing MyPriority (extending Priority as the javadoc says
you shoulds when enlarging the priority set). That already gave some
problems because the _INT fields have package scope. This seems like a
design flaw to me, since I'd like to access these fields in MyPriority (in
com.mycompany.util.logging package), but I managed to bypass via copy/paste
(or so I hope).
Now the next thing I do is writing MyCategory (extends Category) since I
need to add the methods trace(), always() and debug2(). I suppose I must
also implement getInstance() because otherwise I won't be able to create
MyCategory events. And then I have to write a MyHierarchy class since
getInstance() requires a hierarchy and who knows what other classes I'll
have to subclass and I won't even be sure that it will work so...
I start to suspect I'm not on the right track to add custom priorities.
Anyone every tried to add custom priorities?
G.
---------------
Geert Mergan
Java Developer
Email: [EMAIL PROTECTED]
Phone: +32-2-3571765
EuropeanInvestor.com
Lasne Business Park
Chaussée de Louvain 431, Building F
B-1380 Lasne
Phone: +32-2-3571711
Fax: +32-2-3571700
URL: http://www.europeaninvestor.com
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