condition: refinements

2 files changed, 31 insertions, 16 deletions

diff --git a/src/clojure/contrib/condition/Condition.clj b/src/clojure/contrib/condition/Condition.clj
index b3a24340..18449653 100644
--- a/src/clojure/contrib/condition/Condition.clj
+++ b/src/clojure/contrib/condition/Condition.clj
@@ -16,16 +16,28 @@
 (ns clojure.contrib.condition.Condition
   (:gen-class :extends Throwable
               :implements [clojure.lang.IMeta]
-              :state _meta
+              :state state
               :init init
-              :constructors
-              {[clojure.lang.IPersistentMap] []}))
+              :post-init post-init
+              :constructors {[clojure.lang.IPersistentMap]
+                             [String Throwable]}))
 
 (defn -init
-  [meta]
-  [[] meta])
+  "Constructs a Condition object with condition (a map) as its
+  metadata. Also initializes the superclass with the values at :message
+  and :cause, if any, so they are also available via .getMessage and
+  .getCause."
+  [condition]
+  [[(:message condition) (:cause condition)] (atom condition)])
+
+(defn -post-init
+  "Adds :stack-trace to the condition. Drops the bottom 3 frames because
+  they are always the same: implementation details of Condition and raise."
+  [this condition]
+  (swap! (.state this) assoc
+         :stack-trace (into-array (drop 3 (.getStackTrace this)))))
 
 (defn -meta
+  "Returns this object's metadata, the condition"
   [this]
-  (assoc (._meta this)
-    :stack-trace (into-array (drop 3 (.getStackTrace this)))))
+  @(.state this))
diff --git a/src/clojure/contrib/condition/example.clj b/src/clojure/contrib/condition/example.clj
index 36d7b36f..5a7d72ef 100644
--- a/src/clojure/contrib/condition/example.clj
+++ b/src/clojure/contrib/condition/example.clj
@@ -12,28 +12,31 @@
 ;;  Created 09 June 2009
 
 (ns clojure.contrib.condition.example
-  (:use clojure.contrib.condition))
+  (:use (clojure.contrib
+         [condition
+          :only (handler-case print-stack-trace raise *condition*)])))
 
 (defn func [x y]
-  (if (neg? x)
-    (raise :reason :illegal-argument :arg 'x :value x :message "cannot be negative")
-    (+ x y)))
+  "Raises an exception if x is negative"
+  (when (neg? x)
+    (raise :type :illegal-argument :arg 'x :value x))
+  (+ x y))
 
 (defn main
   []
   
   ;; simple handler
   
-  (handler-case :reason
+  (handler-case :type
     (println (func 3 4))
     (println (func -5 10))
     (handle :illegal-argument
-      (print-stack-trace *condition*))
+            (print-stack-trace *condition*))
     (println 3))
 
   ;; multiple handlers
   
-  (handler-case :reason
+  (handler-case :type
     (println (func 4 1))
     (println (func -3 22))
     (handle :overflow
@@ -43,8 +46,8 @@
 
   ;; nested handlers
 
-  (handler-case :reason
-    (handler-case :reason
+  (handler-case :type
+    (handler-case :type
       nil
       nil
       (println 1)