proposed new contrib: java-utils
Stuart Halloway
I would like to pull together functions that help with Java interop
and place them in a new contrib: java-utils. Some examples:
(1) Pull out SteveG's properties fn, currently hidden in the internals
of clojure.contrib.sql
(2) reflective helpers for accessing private and protected values
(3) coercions for Java's irritating types: File/String, URL/String,
IPAddress/String, etc.
(4) Maybe some of the utils currently hiding in Compojure (James,
would that be cool with you? Have you signed/would you sign the
contributor agreement?)
If this is interesting to others (or at least inoffensive) I will move
forward with it.
Are there other little nuggets of Java-interop code that I should also
consider?
Cheers,
Stu
Stephen C. Gilardi
On Apr 3, 2009, at 10:17 AM, Stuart Halloway wrote:
> If this is interesting to others (or at least inoffensive) I will move
> forward with it.
I'm in favor.
I'd also like to get your latest thinking on your suggestions from
some time ago about clojure.contrib.lazy-seqs. If they can be
rewritten as you suggested as functions that return a new sequence
rather than as "def'd" sequences, that's strictly more powerful and
would be an improvement. (One can always use a def'd var to hold such
a function if that's desired in a particular application.)
--Steve
Kyle Schaffrick
Stuart Halloway <stuart....@gmail.com> wrote:
>
> Hi all,
>
> I would like to pull together functions that help with Java interop
> and place them in a new contrib: java-utils. Some examples:
>
>
> If this is interesting to others (or at least inoffensive) I will
> move forward with it.
>
I like it. Sounds like a "Clojure for people who don't know Java APIs"
layer. I'm in that group for the most part.
I do acknowledge and see the value in arguments against doing excessive
wrapping of Java-land, but at the same time, the Java libraries seem
quite baroque at times and can be difficult to understand for people who
haven't been steeped in Java idioms. Sometimes I find myself thinking,
"what on earth do I need to make all these objects for!?" (*cough* NIO
*cough*). But I must remind myself that perhaps such architectures solve
problems that I haven't had to deal with coming from other languages.
It's a tough issue.
> Are there other little nuggets of Java-interop code that I should
> also consider?
>
I would love to see a non-blocking IO API that isn't psychotic. My brain
starts to liquify when I read the NIO API documentation, and from what I
can tell, even seasoned Java folks find it a bit much :)
-Kyle
Stuart Sierra
> (3) coercions for Java's irritating types: File/String, ...
clojure.contrib.duck-streams has "file" but not the others
-the other Stuart
Stuart Halloway
> some time ago about clojure.contrib.lazy-seqs. If they can be
> rewritten as you suggested as functions that return a new sequence
> rather than as "def'd" sequences, that's strictly more powerful and
> would be an improvement. (One can always use a def'd var to hold
> such a function if that's desired in a particular application.)
Steve,
At quick glance it looks to me that all three of the lazy-seqs should
be functions. If you want me to I'll change this and add tests.
Stuart
Stephen C. Gilardi
On Apr 5, 2009, at 4:27 PM, Stuart Halloway wrote:
> At quick glance it looks to me that all three of the lazy-seqs should
> be functions. If you want me to I'll change this and add tests.
Please do. Thanks.
--Steve
Stuart Halloway
functions and do not hold their heads. primes is still a sequence
because it needs to hold past values for efficiency.
Stuart
Perry Trolard
I had occasion to wrap java.util.Properties. If there's interest, may
be a good candidate for c.c.java-utils.
It's pasted in below, & attached in the group at
http://clojure.googlegroups.com/web/props.clj
Feel free to change as you see fit.
Best,
Perry
----
(ns props
; Convenience lib for interacting with java.util.Properties
(:use [clojure.contrib.duck-streams :only (reader writer)]
[clojure.contrib.java-utils :only (the-str)])
(:import (java.util Properties)))
(defn props-to-map
"Convert Properties to map."
[p]
(into {} p))
(defn map-to-props
"Convert map to Properties."
{:tag Properties}
[m]
(let [p (Properties.)]
(doseq [[k v] m]
(.setProperty p (the-str k) (str v)))
p))
(defn read-props
"Read Properties from file into map. Uses duck-streams/reader to
read from file,
so duck-streams/*default-encoding* determines character decoding."
[file]
(props-to-map
(with-open [rdr (reader file)]
(doto (Properties.)
(.load rdr)))))
(defn write-props
"Write Properties from map into file. Uses duck-streams/writer to
write to file,
so duck-streams/*default-encoding* determines character encoding."
{:tag Properties}
([m file] (write-props m file nil))
([m file comments]
(with-open [wtr (writer file)]
(doto (map-to-props m)
(.store wtr comments)))))