+1 to everything Nick said.
On 26 January 2014 16:40, Nick Williams <nicho...@nicholaswilliams.net>wrote: > I would be OK with getting rid of the ordinal. It makes it less enum-like, > but I agree that the ordinal really has little purpose now. The intLevel is > more important. > > Here may be the best approach I can think of for calculating the > StandardLevel-equivalent on instantiation: > > public static Level OFF = new Level("OFF", 0, StandardLevel.OFF) {}; > ... > public static Level ALL = new Level("ALL", Integer.MAX_VALUE, > StandardLevel.ALL); > > ... > > private Level(String name, int intLevel, StandardLevel standardLevel) > { // this is the only c-tor standard levels use > // same logic as current constructor > this.standardLevel = standardLevel; > } > > protected Level(String name, int intLevel) { // this is the only c-tor > custom levels use > this(name, intLevel, Level.calculateStandardLevel(intLevel)); > } > > public enum StandardLevel { > OFF, FATAL, ERROR, WARN, INFO, DEBUG, TRACE, ALL > } > > Thoughts? > > N > > On Jan 26, 2014, at 4:02 PM, Ralph Goers wrote: > > > I do have one other comment. You mention that the ordinal value isn’t > guaranteed because the levels might be instantiated in a different order > each time. An alternative wold be to just get rid of the ordinal. It > isn’t used anywhere by anything and when custom values are added they will > be added after the standard levels, which is correct but might not be what > you would expect. Eliminating that would allow the static initialization > to stay as it is and get rid of the need for synchronization in the > constructor. > > > > Ralph > > > > On Jan 26, 2014, at 12:41 PM, Nick Williams < > nicho...@nicholaswilliams.net> wrote: > > > >> Some (ok, a lot of) feedback: > >> > >> - `private static ConcurrentMap<String, Level> levels` should be final. > >> > >> - `private static Object constructorLock` should be final. In fact, > code inspection flags this as a warning since code synchronizes on it. > >> > >> - The standard Level constants should be instantiated in a static > initializer like in my original code. Otherwise the order they are > instantiated in is unpredictable, and DEBUG (for example) may even have a > different ordinal each time the JVM starts. > >> > >> - Level isn't abstract. However, you use `new Level("xxx", n) {}` > (brackets) for Level.OFF, ExtendedLevels.NOTE, and ExtendedLevels.DETAIL, > but you use `new Level("xxx", n)` (no brackets) for other levels. IMO, > Level should be abstract (so that there's always exactly one instance of > every class that extends Level, just like a real enum), and the levels > should all use {} to construct. However, if we don't make Level abstract, > then we should remove {} from OFF, NOTE, and DETAIL because it's > unnecessary. > >> > >> - The way StdLevel appears in the middle of Level separates its static > fields from its instance fields, constructor, and methods. It makes it > difficult to read. I have to scroll pass StdLevel to see the rest of Level. > Can we please move StdLevel to the bottom of Level? > >> > >> - This is more personal preference, but I don't like abbreviating > things in class names. What is Std? We may know, but does everyone? To > someone unfamiliar with English, Standard is easy to translate, but they > have to first figure out that Std is short for Std. Can be please > un-abbreviate this to StandardLevel? > >> > >> - I disagree with this approach: > >> > >> if (levels.containsKey(name)) { > >> Level level = levels.get(name); > >> if (level.intLevel() != intLevel) { > >> throw new IllegalArgumentException("Level " + name + > " has already been defined."); > >> } > >> ordinal = level.ordinal; > >> } > >> > >> This allows multiple Levels with the same name/intLevel to be > instantiated, which prevents equality testing (level == Level.OFF) from > being 100% deterministic. It should really be this: > >> > >> if (levels.containsKey(name)) { > >> throw new IllegalArgumentException("Level " + name + " > has already been defined."); > >> } > >> > >> - I think we should make all of the methods of Level final. Custom > levels shouldn't be able to change their behavior, IMO. Alternatively, if > we don't make Level abstract, we should make it final. > >> > >> - Level has no JavaDoc. The Level constants in Level have no JavaDoc. > That needs to be fixed. > >> > >> - I'm still not convinced StdLevel/StandardLevel is necessary. It seems > like an anti-pattern to me. From what I can tell (please let me know if I'm > missing something), StdLevel's entire purpose is to allow us to still > switch on the standard levels. I think that's a bad reason to create an > enum whose constants mirror Level. The primary problem with the StdLevel is > that the conversion from a Level to a StdLevel in many cases happens __on > every logging event__. That's going to be hugely inefficient. Really, when > a custom Level is created, it should be created with an equivalent standard > Level (or StdLevel). There are several ways to accomplish this that are > open to discussion, but I don't think the current StdLevel.getStdLevel is > the right approach. One alternative: > >> > >> private final Level standardLevel; > >> > >> protected Level(String name, int level, Level mapToOtherFrameworksAs) > { > >> this(name, level); > >> this.standardLevel = mapToOtherFrameworksAs; > >> } > >> > >> private Level(String name, int level) { > >> // same as now > >> this.standardLevel = this; > >> } > >> > >> public final Level getStandardLevel() { > >> return this.standardLevel; > >> } > >> > >> This does, admittedly, have some problems. Another alternative that I > could also be happy with that keeps the StandardLevel enum: > >> > >> private final StandardLevel standardLevel; > >> > >> protected Level(String name, int level, StandardLevel > mapToOtherFrameworksAs) { > >> this(name, level); > >> this.standardLevel = mapToOtherFrameworksAs; > >> } > >> > >> private Level(String name, int level) { > >> // same as now > >> this.standardLevel = this; > >> } > >> > >> public final StandardLevel getStandardLevel() { > >> return this.standardLevel; > >> } > >> > >> Nick > >> > >> On Jan 26, 2014, at 1:38 PM, Ralph Goers wrote: > >> > >>> I’ve committed the changes. Take a look at ExtendedLevels.java, > ExtendedLevelTest.java and log4j-customLevel.xml in the log4j-core test > directories to see how it works. > >>> > >>> Ralph > >>> > >>> On Jan 26, 2014, at 1:19 AM, Remko Popma <remko.po...@gmail.com> > wrote: > >>> > >>>> I'm very curious! Can't wait to see it. Go for it! > >>>> > >>>> On Sunday, January 26, 2014, Ralph Goers <ralph.go...@dslextreme.com> > wrote: > >>>> I have completed the work on custom levels. It uses a variation of > Nick’s “extensible enum” class. The major difference with what he proposed > is that the custom enums must be declared in a class annotated with > @Plugin(name=“xxxx” category=“Level”) for them to be usable during > configuration. > >>>> > >>>> Are their any objections to me checking this in? I’ll be doing the > commit at around noon Pacific Daylight Time if I don’t hear any. > >>>> > >>>> Ralph > >>>> > >>>> > >>>> > >>>> On Jan 25, 2014, at 7:08 AM, Ralph Goers <ralph.go...@dslextreme.com> > wrote: > >>>> > >>>>> I am working on the implementation of custom levels now. I should > have it done today. > >>>>> > >>>>> Ralph > >>>>> > >>>>> On Jan 24, 2014, at 7:07 PM, Remko Popma <remko.po...@gmail.com> > wrote: > >>>>> > >>>>>> What is the best way to make progress on the custom levels > implementation? > >>>>>> > >>>>>> Do we re-open LOG4J-41 or start a fresh Jira ticket? For > implementation ideas, do we attach files to Jira, or create a branch? > >>>>>> > >>>>>> Remko > >>>>>> > >>>>>> On Saturday, January 25, 2014, Gary Gregory <garydgreg...@gmail.com> > wrote: > >>>>>> On Fri, Jan 24, 2014 at 11:48 AM, Remko Popma < > remko.po...@gmail.com> wrote: > >>>>>> Gary, > >>>>>> > >>>>>> The hard-coded levels were proposed because it seemed that the > extensible enum idea raised by Nick was not going to be accepted. > >>>>>> My original position was that Markers could fulfill the requirement > but Nick and yourself made it clear that this was not satisfactory. > >>>>>> > >>>>>> With extensible enums and markers off the table it seemed that the > hard-coded levels was the only alternative, and discussion ensued about > what these levels should be called and what strength they should have. > >>>>>> > >>>>>> During this discussion, several people, including me, repeatedly > expressed strong reservations about adding pre-defined levels, but by this > time I think people were thinking there was no alternative. > >>>>>> > >>>>>> It looked like we were getting stuck, with half the group moving in > one direction ("add pre-defined levels!") and the other half wanting to > move in another direction ("don't add pre-defined levels!"). I asked that > we re-reviewed our assumptions and try to reach a solution that would > satisfy all users. > >>>>>> > >>>>>> We then decided to explore the option of using extensible enums > again. This is still ongoing, but I haven't seen anyone arguing against > this idea since we started this thread. > >>>>>> > >>>>>> Hard-coded levels and the extensible enum are different solutions > to the same problem. > >>>>>> > >>>>>> Hello All: > >>>>>> > >>>>>> Absolutely not. See my DEFCON example. > >>>>>> Talking about an "extensible enum" is mixing design and > implementation, we are talking about 'custom' and/or 'extensible' levels. > >>>>>> Custom/Extensible levels can be designed to serve one or all of: > >>>>>> > >>>>>> - Allow inserting custom levels between built-in levels. > >>>>>> - Allow for domain specific levels outside of the concept of > built-in levels, the DEFCON example. > >>>>>> - Should the custom levels themselves be extensible? > >>>>>> > >>>>>> Gary > >>>>>> > >>>>>> The extensible enum solution satisfies all of us who are opposed to > adding pre-defined levels, while also satisfying the original requirement > raised by Nick and yourself. Frankly I don't understand why you would still > want the pre-defined levels. > >>>>>> > >>>>>> Remko > >>>>>> > >>>>>> > >>>>>> > >>>>>> On Sat, Jan 25, 2014 at 12:53 AM, Gary Gregory < > garydgreg...@gmail.com> wrote: > >>>>>> On Thu, Jan 23, 2014 at 10:45 PM, Remko Popma < > remko.po...@gmail.com> wrote: > >>>>>> Gary, > >>>>>> > >>>>>> I think that's a very cool idea! > >>>>>> Much more flexible, powerful and elegant than pre-defined levels > could ever be. > >>>>>> > >>>>>> As I wrote: "I am discussing custom levels here with the > understanding that this is a separate topic from what the built-in levels > are." > >>>>>> > >>>>>> I'm not sure why you want to make the features mutually exclusive. > (Some) others agree that these are different features. > >>>>>> > >>>>>> I see two topics: > >>>>>> > >>>>>> - What are the default levels for a 21st century logging framework. > Do we simply blindly copy Log4j 1? Or do we look at frameworks from > different languages and platforms for inspiration? > >>>>>> - How (not if, I think we all agree) should we allow for custom > levels. > >>>>>> > >>>>>> Gary > >>>>>> > >>>>>> It definitely makes sense to design the extensible enum with this > potential usage in mind. > >>>>>> > >>>>>> Remko > >>>>>> > >>>>>> > >>>>>> On Friday, January 24, 2014, Gary Gregory <garydgreg...@gmail.com> > wrote: > >>>>>> I am discussing custom levels here with the understanding that this > is a separate topic from what the built-in levels are. Here is how I > convinced myself that custom levels are a “good thing”. > >>>>>> > >>>>>> No matter which built-in levels exits, I may want custom levels. > For example, I want my app to use the following levels DEFCON1, DEFCON2, > DEFCON3, DEFCON4, and DEFCON5. This might be for one part of my app or a > whole subsystem, no matter, I want to use the built-in levels in addition > to the DEFCON levels. It is worth mentioning that if I want that feature > only as a user, I can “skin” levels in a layout and assign any label to the > built-in levels. If I am also a developer, I want to use DEFCON levels in > the source code. > >>>>>> > >>>>>> > >>>>>> > >>>>>> At first, my code might look like: > >>>>>> > >>>>>> > >>>>>> > >>>>>> logger.log(DefconLevels.DEFCON5, “All is quiet”); > >>>>>> > >>>>>> > >>>>>> > >>>>>> Let’s put aside for now the type of DefconLevels.DEFCON* objects. I > am a user, and I care about my call sites. > >>>>>> > >>>>>> > >>>>>> > >>>>>> What I really want of course is to write: > >>>>>> > >>>>>> > >>>>>> > >>>>>> defconLogger.defcon5(“All is quiet”) > >>>>>> > >>>>>> > >>>>>> > >>>>>> Therefore, I argue that for any “serious” use of a custom level, I > will wrap a Logger in a custom logger class providing call-site friendly > methods like defcon5(String). > >>>>>> > >>>>>> > >>>>>> > >>>>>> So now, as a developer, all I care about is DefConLogger. It might > wrap (or subclass) the Log4J Logger, who knows. The implementation of > DefConLogger is not important to the developer (all I care is that the > class has ‘defconN’ method) but it is important to the configuration > author. This tells me that as a developer I do not care how DefConLogger is > implemented, with custom levels, markers, or elves. However, as > configuration author, I also want to use DEFCON level just like the > built-in levels. > >>>>>> > >>>>>> > >>>>>> > >>>>>> The configuration code co > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>> -- > >>>>>> E-Mail: garydgreg...@gmail.com | ggreg...@apache.org > >>>>>> Java Persistence with Hibernate, Second Edition > >>>>>> JUnit in Action, Second Edition > >>>>>> Spring Batch in Action > >>>>>> Blog: http://garygregory.wordpress.com > >>>>>> Home: http://garygregory.com/ > >>>>>> Tweet! http://twitter.com/GaryGregory > >>>>> > >>>> > >>> > >> > >> > >> --------------------------------------------------------------------- > >> To unsubscribe, e-mail: log4j-dev-unsubscr...@logging.apache.org > >> For additional commands, e-mail: log4j-dev-h...@logging.apache.org > >> > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: log4j-dev-unsubscr...@logging.apache.org > > For additional commands, e-mail: log4j-dev-h...@logging.apache.org > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: log4j-dev-unsubscr...@logging.apache.org > For additional commands, e-mail: log4j-dev-h...@logging.apache.org > > -- Matt Sicker <boa...@gmail.com>