I've added a section on the Wiki under the examples:
http://en.wikibooks.org/wiki/Clojure_Programming/Examples#Invoking_Java_method_through_method_name_as_a_String
Again, thanks!
-Rich
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This is _so_ awesome!!
Thanks a ton for your patient help Tim, and others.
In the end I also had to switch the use of into-array to to-array, since
into-array expects all the elements to be the same type, and my args were of
varying types. Using to-array worked since it cast each element to the
O
> I guess I'm still stuck on how to expand the vector of arguments in place...
One way is (apply function vector) -> (function v1 v2 v3)
> and I'm really not very sure what you're doing with the '&' in the
> parameters for the str-invoke. Is that a way of slurping all the remaining
> parameters
On Sun, Feb 22, 2009 at 4:44 AM, Richard Lyman wrote:
[...]
> user=> (defn str-invoke [instance method-str & args]
> (clojure.lang.Reflector/invokeInstanceMethod instance method-str (into-array
> args)))
> #'user/str-invoke
> user=> (def i "sampleString")
> #'user/i
> user=> (def m "substring")
>
Cool... that looks like it got me past the 'method-as-a-string' problem, but
now I'm getting errors with not finding a matching method on the class by
that name. I'm guessing that this means there was a problem matching the
type signature of the method.
The arguments to the method are stored in a
How embarrassing!
This works much better:
(defn str-invoke [method-str instance & args]
(clojure.lang.Reflector/invokeInstanceMethod instance method-str (to-
array args)))
(let [ts "toString", ct "compareTo"]
(println (str-invoke ts 5))
(println (str-invoke ct 5 4))
(println (str-invoke
Thanks for the quick response! :-)
This works fine when the method name is not in a var, but if you try:
user=> (defmacro my-invoke [method-str instance & args]
`(. ~instance ~(symbol method-str) ~...@args))
nil
user=> (my-invoke "toString" 5)
"5"
user=> (def command "toString")
#'user/command
u
Hi Richard,
As you probably know, Clojure java interop requires the method to be a
symbol:
user=> (. 5 toString)
"5"
So if you want to invoke a method from a string, you can convert the
string to symbol first:
user=> (symbol "toString")
toString
Great! but (. 5 (symbol "toString")) wont work be
On Feb 21, 8:31 am, Richard Lyman wrote:
> I have an instance of the Java class in a variable.
> I have the method arguments in a vector.
> I have the method name as a String.
>
> I've tried so many different ways to invoke that method on that class and
> pass those parameters. I've tried macros,
I have an instance of the Java class in a variable.
I have the method arguments in a vector.
I have the method name as a String.
I've tried so many different ways to invoke that method on that class and
pass those parameters. I've tried macros, reflection, and read/eval. None of
the ways I've trie
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