From 4bb4c101431a6402c9603d35db244c2fd5aeb4c4 Mon Sep 17 00:00:00 2001
From: Stuart Halloway <stu@thinkrelevance.com>
Date: Mon, 17 Sep 2012 07:45:36 -0400
Subject: [PATCH] interface IExceptionInfo

---
 src/clj/clojure/core.clj                 |    8 ++++----
 src/jvm/clojure/lang/ExceptionInfo.java  |    2 +-
 src/jvm/clojure/lang/IExceptionInfo.java |   20 ++++++++++++++++++++
 test/clojure/test_clojure/errors.clj     |    7 +++++++
 4 files changed, 32 insertions(+), 5 deletions(-)
 create mode 100644 src/jvm/clojure/lang/IExceptionInfo.java

diff --git a/src/clj/clojure/core.clj b/src/clj/clojure/core.clj
index 4a6e61f..50fb33e 100644
--- a/src/clj/clojure/core.clj
+++ b/src/clj/clojure/core.clj
@@ -4287,7 +4287,7 @@
     (with-out-str
      (apply println xs)))
 
-(import clojure.lang.ExceptionInfo)
+(import clojure.lang.ExceptionInfo clojure.lang.IExceptionInfo)
 (defn ex-info
   "Alpha - subject to change.
    Create an instance of ExceptionInfo, a RuntimeException subclass
@@ -4300,12 +4300,12 @@
 
 (defn ex-data
   "Alpha - subject to change.
-   Returns exception data (a map) if ex is an ExceptionInfo.
+   Returns exception data (a map) if ex is an IExceptionInfo.
    Otherwise returns nil."
   {:added "1.4"}
   [ex]
-  (when (instance? ExceptionInfo ex)
-    (.getData ^ExceptionInfo ex)))
+  (when (instance? IExceptionInfo ex)
+    (.getData ^IExceptionInfo ex)))
 
 (defmacro assert
   "Evaluates expr and throws an exception if it does not evaluate to
diff --git a/src/jvm/clojure/lang/ExceptionInfo.java b/src/jvm/clojure/lang/ExceptionInfo.java
index 1ebc83c..7ccaa0b 100644
--- a/src/jvm/clojure/lang/ExceptionInfo.java
+++ b/src/jvm/clojure/lang/ExceptionInfo.java
@@ -15,7 +15,7 @@ package clojure.lang;
  * richer semantics for exceptions should use this in lieu of defining project-specific
  * exception classes.
  */
-public class ExceptionInfo extends RuntimeException{
+public class ExceptionInfo extends RuntimeException implements IExceptionInfo {
     public final IPersistentMap data;
 
     public ExceptionInfo(String s, IPersistentMap data) {
diff --git a/src/jvm/clojure/lang/IExceptionInfo.java b/src/jvm/clojure/lang/IExceptionInfo.java
new file mode 100644
index 0000000..be7dc80
--- /dev/null
+++ b/src/jvm/clojure/lang/IExceptionInfo.java
@@ -0,0 +1,20 @@
+/**
+ * Copyright (c) Rich Hickey. All rights reserved.
+ * The use and distribution terms for this software are covered by the
+ * Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+ * which can be found in the file epl-v10.html at the root of this distribution.
+ * By using this software in any fashion, you are agreeing to be bound by
+ * the terms of this license.
+ * You must not remove this notice, or any other, from this software.
+ */
+
+package clojure.lang;
+
+/**
+ * Interface for exceptions that carry data (a map) as additional payload. Clojure 
+ * programs that need richer semantics for exceptions should use this in lieu of 
+ * defining project-specific exception classes.
+ */
+public interface IExceptionInfo {
+    public IPersistentMap getData();
+}
diff --git a/test/clojure/test_clojure/errors.clj b/test/clojure/test_clojure/errors.clj
index 67e51d6..98cab48 100644
--- a/test/clojure/test_clojure/errors.clj
+++ b/test/clojure/test_clojure/errors.clj
@@ -45,3 +45,10 @@
     (is (thrown-with-msg? IllegalArgumentException
                           (re-pattern (format msg-regex-str *ns*))
                           (macroexpand form)))))
+
+(deftest extract-ex-data
+  (try
+   (throw (ex-info "example error" {:foo 1}))
+   (catch Throwable t
+     (is (= {:foo 1} (ex-data t)))))
+  (is (nil? (ex-data (RuntimeException. "example non ex-data")))))
-- 
1.7.3.5