Creating a ServletContextListener that will run the functions specifi…

…ed in the context parameters context-init and context-destroy when the application is initialized or stopped. Both parameters are optional. Also included a small utility function to convert context params to a map.

The project now needs lein 2.0.0-preview10 to make use of the "provided" dependencies.

README.md

@@ -1,25 +1,26 @@
 #Ring java servlet
 
 Allows you to embed ring handlers in existing java web applications without having to add an AOT phase to your build process, by providing you with a generic way to declare servlets in your web.xml, and where the clojure ring handler is located.
+It also provides a ServletContextListener which can be configured to run a function when the web app is initialized and destroyed.
 
-##Example
-
-### Add the Ring java servlet dependency to your project
+##Setup
 Add this project as a dependency of your project. By means of transitive dependencies magic, you''ll need to add no other dependency.
 
 ring-java-servlet is distributed on clojars.org as a maven artifact, with following coordinates:
 
 * groupId=org.lpetit.ring
 * artifactId=ring-java-servlet
-* version=0.1.0 (as of the time where this README was last updated)
+* version=0.2.0 (as of the time where this README was last updated)
 
 ring-java-servlet artifacts are currently only available on clojars.org
 
+##Ring handler example
+
 ### Create your Ring handler
 Write a clojure ring handler and place it somewhere in your source/resources folder (so that your build system adds it to the webapp classpath, e.g. places it in WEB-INF/classes folder of your webapp) :
 
     ; file lpetit.ring_test.clj
-    (ns lpetit.ring-test
+    (ns lpetit.ring-test)
     (defn hello [req]
       {:status 200
        :headers {"Content-Type" "text/html"}
@@ -41,5 +42,36 @@ Write a clojure ring handler and place it somewhere in your source/resources fol
     </servlet-mapping>
 
 ### Test it
-That''s all. Next time you build your webapp and start it, you should see a "Hello world from ring java servlet" welcome message at http://the-server:the-port/<your-webapp-context>/foo.some-extension
+That's all. Next time you build your webapp and start it, you should see a "Hello world from ring java servlet" welcome message at http://the-server:the-port/<your-webapp-context>/foo.some-extension
+
+##ServletContextListener example
+
+### Create startup and shutdown functions
+Any clojure function with one parameter can be used as the startup or shutdown function. The RingServletContextListener will pass the ServletContext to the function. There is also a small utility function to convert the context parameters to a clojure map.
+
+    ; file lpetit.ring_test.clj
+    (ns lpetit.context-test
+      (:require [org.lpetit.ring.servlet.util :as util])
+
+    (defn start-up [ctx]
+      (println "Starting app with params: " (util/context-params ctx))
+
+    (defn shutdown [ctx]
+      (println "Stopping app with params: " (util/context-params ctx))
+
+
+### Declare the ServletContextListener in your web.xml
+
+Specify which funtions to run at start/stop with the `context-init` and `context-destroy` context parameters. Both parameters are optional.
 
+    <context-param>
+       <param-name>context-init</param-name>
+       <param-value>lpetit.context-test/start-up</param-value>
+    </context-param>
+    <context-param>
+       <param-name>context-destroy</param-name>
+       <param-value>lpetit.context-test/shutdown</param-value>
+    </context-param>
+    <listener>
+       <listener-class>org.lpetit.ring.servlet.RingServletContextListener</listener-class>
+    </listener>

project.clj

@@ -1,6 +1,8 @@
-(defproject org.lpetit.ring/ring-java-servlet "0.1.0"
+(defproject org.lpetit.ring/ring-java-servlet "0.2.0"
   :description "Ring generic servlet for using ring without AOT."
   :url "http://github.com/laurentpetit/ring-java-servlet"
-  :dependencies [[ring/ring-servlet "0.3.5" :exclusions [javax.servlet/servlet-api]]]
-  :dev-dependencies [[javax.servlet/servlet-api "2.5"]]
-  :aot [org.lpetit.ring.servlet.RingHttpServlet])
+  :dependencies [[ring/ring-servlet "1.1.0" :exclusions [javax.servlet/servlet-api]]]
+  :profiles {:provided
+                 {:dependencies
+                  [[javax.servlet/servlet-api "2.5"]]}}
+  :aot [org.lpetit.ring.servlet.RingHttpServlet org.lpetit.ring.servlet.RingServletContextListener])

src/org/lpetit/ring/servlet/RingHttpServlet_impl.clj

@@ -1,17 +1,17 @@
 (ns org.lpetit.ring.servlet.RingHttpServlet-impl
   (:require [ring.util.servlet :as s])
+  (:use org.lpetit.ring.servlet.util)
   (:import org.lpetit.ring.servlet.RingHttpServlet))
 
 (defn -initState [] [[] (atom {})])
 
 (defn -init-void [this]
-  (let [[n h] (map symbol ((juxt namespace name) (symbol (.getInitParameter this "handler"))))]
-    (require n)
-    (swap! 
+  (let [resolved-fn (require-and-resolve (.getInitParameter this "handler"))]
+    (swap!
       (.state this)
       assoc
       :service-fn
-      (s/make-service-method (ns-resolve (the-ns n) h)))))
+      (s/make-service-method resolved-fn))))
 
 (defn -service [this req resp]
   ((-> this .state deref :service-fn) this req resp))

src/org/lpetit/ring/servlet/RingServletContextListener.clj

@@ -0,0 +1,19 @@
+(ns org.lpetit.ring.servlet.RingServletContextListener
+  (:use org.lpetit.ring.servlet.util)
+  (:gen-class :implements [javax.servlet.ServletContextListener])
+  (:import [javax.servlet ServletContextEvent]))
+
+(defn run [contextEvent symbol-str]
+  (let [ctx (.getServletContext contextEvent)]
+    (if-let [the-fn (.getInitParameter ctx symbol-str)]
+      (let [resolved-fn (require-and-resolve the-fn)]
+        (resolved-fn ctx)))))
+
+(defn -contextInitialized [this ^ServletContextEvent contextEvent]
+  (run contextEvent "context-init"))
+
+(defn -contextDestroyed [this ^ServletContextEvent contextEvent]
+  (run contextEvent "context-destroy"))
+
+
+

src/org/lpetit/ring/servlet/util.clj

@@ -0,0 +1,13 @@
+(ns org.lpetit.ring.servlet.util
+  (:import [javax.servlet ServletContext]))
+
+(defn require-and-resolve [symbol-str]
+  (let [[n h] (map symbol ((juxt namespace name) (symbol symbol-str)))]
+    (require n)
+    (ns-resolve (the-ns n) h)))
+
+(defn context-params [^ServletContext ctx]
+  "Given a servlet context, it returns a map with all the context parameters. Keys are keywords."
+  (into {} (for [param (enumeration-seq (.getInitParameterNames ctx))
+                 :let [value (.getInitParameter ctx param)]]
+             [(keyword param) value])))