JUZU-48 : Remove unnecessary bottleneck when retrieving Requests

Actually, there a big bottleneck JUZU applications
Each time a JUZU application is displayed in a page, all other HTTP requests that wants to display any other page that uses JUZU will be blocked because of one operation in JUZU application lifecycle.
In fact, inside the "retrieve the response" phase, the operation "get the filters beans associated to the Stage type(Unmarshaling, Handler, Lifecycle, Invoke)" is synchronized (blocker, one operation at a time).
The filters are SINGLETON beans, so we should put those beans in the JUZU controller context once for all.

core/src/main/java/juzu/impl/plugin/controller/ControllerService.java

@@ -24,6 +24,7 @@
 import juzu.impl.request.ContextualParameter;
 import juzu.impl.request.ControlParameter;
 import juzu.impl.request.ControllerHandler;
+import juzu.impl.request.RequestFilter;
 import juzu.impl.value.ValueType;
 import juzu.request.Phase;
 import juzu.io.UndeclaredIOException;
@@ -36,11 +37,13 @@
 import juzu.request.RequestParameter;
 
 import javax.inject.Inject;
+
 import java.io.IOException;
 import java.lang.reflect.Method;
 import java.lang.reflect.UndeclaredThrowableException;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.List;
 
 /** @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a> */
 public class ControllerService extends ApplicationService {
@@ -51,6 +54,9 @@ public class ControllerService extends ApplicationService {
   /** . */
   final ArrayList<ValueType<?>> valueTypes = new ArrayList<ValueType<?>>();
 
+  /** . */
+  final List<RequestFilter<?>>                             filters = new ArrayList<RequestFilter<?>>();
+
   /** . */
   @Inject
   private Application application;
@@ -83,6 +89,20 @@ public ServiceDescriptor init(ServiceContext context) throws Exception {
   public InjectionContext<?, ?> getInjectionContext() {
     return application.getInjectionContext();
   }
+
+  public List<RequestFilter<?>> getFilters() {
+    if (filters.isEmpty()) {
+      synchronized (filters) {
+        if (filters.isEmpty()) {
+          // Build the filter list
+          for (RequestFilter<?> filter : getInjectionContext().resolveInstances(RequestFilter.class)) {
+            filters.add(filter);
+          }
+        }
+      }
+    }
+    return filters;
+  }
 
   public <T> ValueType<T> resolveValueType(Class<T> type) {
     for (int i = 0;i < valueTypes.size();i++) {

core/src/main/java/juzu/impl/request/Stage.java

@@ -64,7 +64,7 @@ public Stage(Request request) {
 
     // Build the filter list
     List<RequestFilter<?>> filters = new ArrayList<RequestFilter<?>>();
-    for (RequestFilter<?> filter : request.controllerPlugin.getInjectionContext().resolveInstances(RequestFilter.class)) {
+    for (RequestFilter<?> filter : request.controllerPlugin.getFilters()) {
       if (getClass().isAssignableFrom(filter.getStageType())) {
         filters.add(filter);
       }