Re: Soften interface for javax.management.ObjectName.getInstance and friends
Hi Dave, I'm not sure this is quite a good idea because order doesn't count when comparing ObjectNames. So the folder analogy would just be a lure: /a/b/c would be equal to /a/c/b That said - I can see value in trying to get rid of the legacy Hashtable - so adding a new method that takes a Map wouldn't necessarily be a bad thing :-) A work around for your use case would be to use: static ObjectName getInstance(String name) instead of static ObjectName getInstance(String domain Hashtable table) An object name has both a string representation and a canonical representation. IIRC we did try to preserve the original string representation, even if it's not canonical. It's also preserved in the serial form. See: https://docs.oracle.com/javase/8/docs/api/javax/management/ObjectName.html#getKeyPropertyListString-- Hope this helps, -- daniel On 24/02/17 00:17, Dave Brosius wrote: Greetings. the method public static ObjectName getInstance(String domain, Hashtable table) throws MalformedObjectNameException { return new ObjectName(domain, table); } in javax.management.ObjectName allows for a provided Hashtable to specify properties for the objectname. The semantics of an ObjectName don't consider the order of these properties, however certain tools like jconsole (when used as a name for a jmx property) does consider the order. If you wish to create a folder structure to report metrics in jmx, you need to use this properties map to specify the folder names. JConsole, then, uses order of iteration to determine the order of the folder hierarchy. Suppose you want a folder hierarchy similar to a package name, you may specify properties like table.put("a0", "com"); table.put("a1", "acme"); table.put("name", "MyMetric"); in hopes of producing a metric in JConsole in the folder structure, com/acme/MyMetric. The problem is of course, that the argument is a Hashtable, not a Map, and so the items are not ordered at all, yet JConsole uses iteration order to build the path, so you may get acme/ao/MyMetric or MyMetric/acme/ao or . This means if you really want to have ordered packages, you have to derive from Hashtable, and override the entrySet() method, including that set's iterator() to return the values in the order you wish to have them shown. That is really janky. I'm proposing that the interface for getInstance be softened to public static ObjectName getInstance(String domain, Map table) as well as public ObjectName(String domain, Map table) thoughts?
Re: Soften interface for javax.management.ObjectName.getInstance and friends
You should send this topic to serviceability-dev which is the mailing list for JMX and other serviceability related issues. Mandy > On Feb 23, 2017, at 4:17 PM, Dave Brosius wrote: > > Greetings. the method > > public static ObjectName getInstance(String domain, > Hashtable table) >throws MalformedObjectNameException { >return new ObjectName(domain, table); >} > > in javax.management.ObjectName allows for a provided Hashtable to specify > properties for the objectname. > > The semantics of an ObjectName don't consider the order of these properties, > however certain tools like jconsole (when used as a name for a jmx property) > does consider the order. > > If you wish to create a folder structure to report metrics in jmx, you need > to use this properties map to specify the folder names. JConsole, then, uses > order of iteration to determine the order of the folder hierarchy. > > Suppose you want a folder hierarchy similar to a package name, you may > specify properties like > > table.put("a0", "com"); > table.put("a1", "acme"); > table.put("name", "MyMetric"); > > in hopes of producing a metric in JConsole in the folder structure, > com/acme/MyMetric. > > The problem is of course, that the argument is a Hashtable, not a Map, and so > the items are not ordered at all, yet JConsole uses iteration order to build > the path, so you may get > > acme/ao/MyMetric or MyMetric/acme/ao or . > > This means if you really want to have ordered packages, you have to derive > from Hashtable, and override the entrySet() method, including that set's > iterator() to return the values in the order you wish to have them shown. > > That is really janky. > > I'm proposing that the interface for getInstance be softened to > > public static ObjectName getInstance(String domain, > Map table) > > as well as > > public ObjectName(String domain, Map table) > > thoughts? > >
Soften interface for javax.management.ObjectName.getInstance and friends
Greetings. the method public static ObjectName getInstance(String domain, Hashtable table) throws MalformedObjectNameException { return new ObjectName(domain, table); } in javax.management.ObjectName allows for a provided Hashtable to specify properties for the objectname. The semantics of an ObjectName don't consider the order of these properties, however certain tools like jconsole (when used as a name for a jmx property) does consider the order. If you wish to create a folder structure to report metrics in jmx, you need to use this properties map to specify the folder names. JConsole, then, uses order of iteration to determine the order of the folder hierarchy. Suppose you want a folder hierarchy similar to a package name, you may specify properties like table.put("a0", "com"); table.put("a1", "acme"); table.put("name", "MyMetric"); in hopes of producing a metric in JConsole in the folder structure, com/acme/MyMetric. The problem is of course, that the argument is a Hashtable, not a Map, and so the items are not ordered at all, yet JConsole uses iteration order to build the path, so you may get acme/ao/MyMetric or MyMetric/acme/ao or . This means if you really want to have ordered packages, you have to derive from Hashtable, and override the entrySet() method, including that set's iterator() to return the values in the order you wish to have them shown. That is really janky. I'm proposing that the interface for getInstance be softened to public static ObjectName getInstance(String domain, Map table) as well as public ObjectName(String domain, Map table) thoughts?