BZ 1035723 BZ 1035722 do not load the servlet invoker until we get th…

…e first request.

Then, don't log an error message unless we got alot of these, and log at debug level.
This error message is rarely indicative of a problem.

Cherry-Pick master 809d86f
Signed-off-by: Jay Shaughnessy <jshaughn@redhat.com>

modules/enterprise/gui/remoting-war/src/main/java/org/rhq/enterprise/communications/servlet/ServerInvokerServlet.java

@@ -20,14 +20,19 @@
 package org.rhq.enterprise.communications.servlet;
 
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import javax.management.MBeanServer;
 import javax.management.MBeanServerInvocationHandler;
 import javax.management.MalformedObjectNameException;
 import javax.management.ObjectName;
 import javax.servlet.ServletConfig;
 import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
 
+import org.jboss.logging.Logger;
 import org.jboss.remoting.transport.servlet.ServletServerInvokerMBean;
 
 /**
@@ -42,6 +47,56 @@
 public class ServerInvokerServlet extends org.jboss.remoting.transport.servlet.web.ServerInvokerServlet {
     private static final long serialVersionUID = 1L;
 
+    private static Logger log = Logger.getLogger(ServerInvokerServlet.class);
+
+    private ServletConfig servletConfig;
+    private AtomicInteger evilLogMessageCount = new AtomicInteger(0);
+    private final AtomicBoolean alreadyInitialized = new AtomicBoolean(false);
+
+    @Override
+    public void init(ServletConfig config) throws ServletException {
+        // purposefully do not call init(config) - we can't have the superclass try to get
+        // the servletInvoker yet and risk getting that dreaded and evil log message!
+        super.init();
+        this.servletConfig = config;
+    }
+
+    @Override
+    protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException,
+        java.io.IOException {
+
+        // find the servlet invoker now - catch exceptions and avoid logging so we don't scare people
+        if (initServletInvokerNow()) {
+            super.processRequest(request, response);
+        } else {
+            // tell the client we can't process the request
+            response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE, "Server is not ready yet");
+        }
+    }
+
+    /**
+     * Performs the "real" init so the JBoss/Remoting superclass loads the servlet invoker.
+     * This returns true if we can keep going; false if an error occurred and we can't process the current request.
+     */
+    private boolean initServletInvokerNow() {
+        try {
+            synchronized (alreadyInitialized) {
+                if (!alreadyInitialized.get()) {
+                    super.init(this.servletConfig);
+                    alreadyInitialized.set(true);
+                }
+            }
+            return true;
+        } catch (Exception e) {
+            // only log a message (at debug level) if we see this lots of times, but only every 10th time
+            int msgCount = evilLogMessageCount.incrementAndGet();
+            if ((msgCount % 10 == 0) && (msgCount >= 100)) {
+                log.debug(e);
+            }
+            return false;
+        }
+    }
+
     /**
      * Returns the servlet server invoker. In our implementation, this always returns
      * the MBean.
@@ -89,4 +144,4 @@ protected ServletServerInvokerMBean getInvokerFromInvokerName(ServletConfig conf
         return (ServletServerInvokerMBean) MBeanServerInvocationHandler.newProxyInstance(mbeanServer,
             theInvokerObjectName, ServletServerInvokerMBean.class, false);
     }
-}
+}