added bean, which creates a live read-only map of an object's javabeans properties

1 files changed, 25 insertions, 0 deletions

diff --git a/src/boot.clj b/src/boot.clj
index ea9842df..ad3d540e 100644
--- a/src/boot.clj
+++ b/src/boot.clj
@@ -1192,6 +1192,30 @@
 
 (. (the-var defmacro*) (setMacro))
 
+(defn bean [#^Object x]
+  (let [c (. x (getClass))
+	pmap (reduce (fn [m #^java.beans.PropertyDescriptor pd]
+			 (let [name (. pd (getName))
+			       method (. pd (getReadMethod))]
+			   (if (and method (zero? (alength (. method (getParameterTypes)))))
+			     (assoc m (keyword name) (fn [] (. method (invoke x nil))))
+			     m)))
+		     {}
+		     (seq (.. java.beans.Introspector
+			      (getBeanInfo c)
+			      (getPropertyDescriptors))))
+	v (fn [k] ((pmap k)))]
+    (implement [clojure.lang.IPersistentMap]
+      (containsKey [k] (contains? pmap k))
+      (entryAt [k] (when (contains? pmap k) (new clojure.lang.MapEntry k (v k))))
+      (valAt ([k] (v k))
+	     ([k default] (if (contains? pmap k) (v k) default)))
+      (count [] (count pmap))
+      (seq [] ((fn this [pseq]
+		  (when pseq
+		    (lazy-cons (new clojure.lang.MapEntry (first pseq) (v (first pseq)))
+			       (this (rest pseq))))) (keys pmap))))))
+
 (export
 	'(  load-file load
 		list cons conj defn
@@ -1257,5 +1281,6 @@
 		nthrest
 		string? symbol? map? seq? vector?
 		let* fn* defn* defmacro*
+		bean
 	))