Interesting, thanks for the new perspective! Using YAML seems more flexible than what I was thinking, particularly since Clojure apparently doesn't make me worry too much about the specific kind of sequence/map I'm using.
(Yeah, I have an app which sends serialized objects all over the place, and one thing I didn't like was how brittle my serialization tool was when I made a little change to object definitions. (This is in Common Lisp.) In my next release, I'd like to make it less strict.) Tayssir On Dec 2, 11:12 am, Luc Prefontaine <[EMAIL PROTECTED]> wrote: > I use YAML to serialize. I needed a simple way to pass Maps, Lists and > Vector between java, Ruby and Clojure components. > I change the classes of Clojure in the YAML output to java.util.Map, > List and so on to remove dependencies > on Clojure classes while retaining the ability to walk through the > structures using these basic types in "foreign" > components. In Java it's pretty obvious, Map, List and Vectors are > always present and in Ruby these things are > also part of the core language. > > Have a look athttp://jyaml.sourceforge.net/ > > Essentially it sums up to something like this: > > (def *YAML-config* (YamlConfig.)) > (. *YAML-config* load yamlmsg) ;; Loads a YAML representation to an > equivalent object representation > (. *YAML-config* dump msg) ;; Dumps an object to a YAML string. > > I extended a bit the library to deal transparently with types like > java.sql.Date (I deal with several databases) > but nothing else was changed. Just beware of binary characters in your > strings. I encoded these with XML/HTML escapes before serializing. > I need to talk to the maintainer about this issue. > > Never liked Java serialization mainly because: > > a) The the binary representation of classes has to be exactly the same > at both ends otherwise you are stuck in a dead end. > > b) You need that [EMAIL PROTECTED]@[EMAIL PROTECTED] Serializable interface > which should be > implemented by default everywhere by Java, not you. > An embedded object misses the interface ? Well find it.. at run-time > and good luck. > > c) It's not easy to debug since it's not human readable. > > d) It makes upgrading a distributed environment a pain in the ass since > you may have upgrade everything even if no major > changes occurred in your classes. You added a method irrelevant to > most of the components in a class ? > That single change forces you to upgrade everything... this is a > typical example of developpers disconnected from real life. > In real life your systems are running and you may not be able to > interrupt services for a long period to upgrade them > all at once. You may have to do so in multiple steps and without > interrupting the service. > > e) I want the data serialized, not the access to it... > > If size of the YAML output becomes an issue then zip it. > > Luc > > On Tue, 2008-12-02 at 00:57 -0800, Tayssir John Gabbour wrote: > > Hi! > > > How should I approach serialization? I made a little test function > > which serializes and deserializes Clojure objects. It works for > > strings, integers, symbols, LazilyPersistentVectors and.. oddly.. > > PersistentHashMaps that have exactly one element. (My Clojure is about > > a month old.) > > > But for other things, like keywords and most PersistentHashMaps, it > > throws NotSerializableException. > > > My imagined possible solutions: > > > * Implement Serializable for Clojure data -- but is it possible in a > > dynamic "Hey I'll just write a new method!" way? > > > * Go into Clojure's source and implement Serializable to the Java > > classes. > > > My end goal is using a nonrelational DB like Tokyo Cabinet or > > BerkeleyDB. > > > Thanks, > > Tayssir > > > PS: Here's my test code: > > > (defn my-identity "Copies obj through serialization and > > deserialization." > > [obj] > > (let [byte-out (new java.io.ByteArrayOutputStream) > > obj-out (new java.io.ObjectOutputStream byte-out)] > > (try (.writeObject obj-out obj) > > (finally (.close obj-out))) > > (let [obj-in (new java.io.ObjectInputStream > > (new java.io.ByteArrayInputStream (.toByteArray > > byte-out)))] > > (try (.readObject obj-in) > > (finally (.close obj-in)))))) > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
