From c960607c4f3a4d099aea4d0a0dc1548b3e29feca Mon Sep 17 00:00:00 2001
From: Christian Kaltepoth <christian@kaltepoth.de>
Date: Mon, 14 Jul 2014 08:01:48 +0200
Subject: [PATCH] DispatchType now caches the DispatcherTypeProvider list on a
 per request basis

---
 .../rewrite/servlet/config/DispatchType.java  | 27 +++++++++++++------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/config-servlet/src/main/java/org/ocpsoft/rewrite/servlet/config/DispatchType.java b/config-servlet/src/main/java/org/ocpsoft/rewrite/servlet/config/DispatchType.java
index 405b19f44..b5826fad0 100644
--- a/config-servlet/src/main/java/org/ocpsoft/rewrite/servlet/config/DispatchType.java
+++ b/config-servlet/src/main/java/org/ocpsoft/rewrite/servlet/config/DispatchType.java
@@ -37,18 +37,13 @@
  */
 public class DispatchType extends HttpCondition
 {
+   private final static String PROVIDER_KEY = DispatchType.class.getName() + "_PROVIDERS";
+
    private final DispatcherType type;
-   private final List<DispatcherTypeProvider> providers;
 
    private DispatchType(final DispatcherType type)
    {
       this.type = type;
-
-      // for performance reasons only create the list of providers once
-      providers = Iterators.asList(
-               ServiceLoader.loadTypesafe(DispatcherTypeProvider.class).iterator());
-      Collections.sort(providers, new WeightedComparator());
-
    }
 
    @Override
@@ -66,7 +61,7 @@ public boolean evaluateHttp(final HttpServletRewrite event, final EvaluationCont
     */
    private DispatcherType getDispatcherType(final HttpServletRewrite event)
    {
-      for (DispatcherTypeProvider provider : providers) {
+      for (DispatcherTypeProvider provider : getDispatcherTypeProviders(event)) {
          DispatcherType dispatcherType = provider.getDispatcherType(event.getRequest(), event.getServletContext());
          if (dispatcherType != null) {
             return dispatcherType;
@@ -75,6 +70,22 @@ private DispatcherType getDispatcherType(final HttpServletRewrite event)
       throw new IllegalStateException("Unable to determine dispatcher type of current request");
    }
 
+   /**
+    * Simple caching mechanism for the providers on a per request basis
+    */
+   @SuppressWarnings("unchecked")
+   private List<DispatcherTypeProvider> getDispatcherTypeProviders(HttpServletRewrite event)
+   {
+      List<DispatcherTypeProvider> providers = (List<DispatcherTypeProvider>)
+               event.getRequest().getAttribute(PROVIDER_KEY);
+      if (providers == null) {
+         providers = Iterators.asList(ServiceLoader.loadTypesafe(DispatcherTypeProvider.class).iterator());
+         Collections.sort(providers, new WeightedComparator());
+         event.getRequest().setAttribute(PROVIDER_KEY, providers);
+      }
+      return providers;
+   }
+
    /**
     * Create a {@link DispatchType} condition that ensures the current {@link HttpServletRewrite} is a
     * {@link DispatcherType#FORWARD}