Fixed markdown, added docu, added resource for uptime

README.md

@@ -1,9 +1,34 @@
-##A 9 kB WAR Ping For JavaEE 7 Application Servers
+# Tiny Ping For JavaEE 7 Application Servers
 
-Ping exposes via a convenient URI basic health / jndi / jvm and OS information.
+Ping exposes basic health, JNDI, JVM and OS metrics via a convenient URI, 
+which enables an easy integration into application monitoring solutions
+and smoke tests. The whole WAR file is only a couple of kilobytes in size.
 
-Tested with GlassFish, Payara, TomEE, WLP and Wildfly
+Tested with GlassFish, Payara, TomEE, WebSphere Liberty and Wildfly.
 
-###Installation:
+## Features:
+
+  * Echo Resource `/resources/pings/echo/{message}`
+  * List system properties `/resources/pings/system-properties`
+  * List environment variables `/resources/pings/environment-variables` 
+  * List java: namespace `/resources/pings/jndi/java:`
+  * List java:comp/env namespace `/resources/pings/jndi/java:comp/env`
+  * List jave:global namespace `/resources/pings/jndi/java:global`
+  * Start boot time `/resources/health/start-time`
+  * Uptime in milliseconds `/resources/health/uptime`
+  * Current memory stats `/resources/health/current-memory`
+  * Operating system stats `/resources/health/os-info`
+
+## Installation:
 
 Drop the WAR https://github.com/AdamBien/ping/releases/ into your autodeploy folder and access the application with http://localhost:[YOUR_PORT]/ping
+
+## Build:
+
+Ping can be built with Maven like this:
+
+    mvn clean package
+
+Your WAR file will be written to the following directory:
+
+    target/ping.war

src/main/java/com/airhacks/ping/boundary/HealthResource.java

@@ -1,6 +1,8 @@
 package com.airhacks.ping.boundary;
 
 import com.airhacks.ping.control.ServerWatch;
+import java.time.ZonedDateTime;
+import java.time.temporal.ChronoUnit;
 import javax.inject.Inject;
 import javax.json.Json;
 import javax.json.JsonObject;
@@ -28,6 +30,13 @@ public String bootTime() {
         return this.watch.getDateTime().toString();
     }
 
+    @GET
+    @Path("/uptime")
+    @Produces(MediaType.TEXT_PLAIN)
+    public String uptime() {
+        return Long.toString(ChronoUnit.MILLIS.between(this.watch.getDateTime(), ZonedDateTime.now()));
+    }
+
     @GET
     @Path("/current-memory")
     public JsonObject availableHeap() {

src/main/webapp/index.html

@@ -35,6 +35,9 @@ <h2>Health</h2>
             <article>
                 <a href="./resources/health/start-time">Start (boot) time</a>
             </article>
+            <article>
+                <a href="./resources/health/uptime">Uptime in milliseconds</a>
+            </article>
             <article>
                 <a href="./resources/health/current-memory">Current memory stats</a>
             </article>