Improve implementation of double-check idiom by using a temp var to r…

…educe the number of accesses to the volatile field in the common scenario
wildfly · Oct 27, 2015 · b8f0a64 · b8f0a64
1 parent a6fe290
commit b8f0a64
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Showing 2 changed files with 48 additions and 41 deletions.
diff --git a/...ices/server-integration/src/main/java/org/jboss/as/webservices/injection/WSComponent.java b/...ices/server-integration/src/main/java/org/jboss/as/webservices/injection/WSComponent.java
@@ -46,18 +46,21 @@ public WSComponent(final WSComponentCreateService createService) {
     }
 
     public BasicComponentInstance getComponentInstance() {
-       if (wsComponentInstance == null) {
-           synchronized (lock) {
-               if (wsComponentInstance == null && reference == null) {
-                   wsComponentInstance = (BasicComponentInstance) createInstance();
-               }
-               if (wsComponentInstance == null && reference != null) {
-                   wsComponentInstance = (BasicComponentInstance) this.createInstance(reference.getInstance());
-               }
-           }
-       }
-       return wsComponentInstance;
-    }
+        BasicComponentInstance result = wsComponentInstance;
+        if (result == null) {
+            synchronized (lock) {
+                result = wsComponentInstance;
+                if (result == null) {
+                    if (reference == null) {
+                        wsComponentInstance = result = (BasicComponentInstance) createInstance();
+                    } else {
+                        wsComponentInstance = result = (BasicComponentInstance) this.createInstance(reference.getInstance());
+                    }
+                }
+            }
+        }
+        return result;
+     }
 
     public void setReference(ManagedReference reference) {
         this.reference = reference;

diff --git a/...egration/src/main/java/org/jboss/as/webservices/invocation/AbstractInvocationHandler.java b/...egration/src/main/java/org/jboss/as/webservices/invocation/AbstractInvocationHandler.java
@@ -50,7 +50,7 @@
  */
 abstract class AbstractInvocationHandler extends org.jboss.ws.common.invocation.AbstractInvocationHandler {
 
-   private ServiceName componentViewName;
+   private volatile ServiceName componentViewName;
    private volatile ComponentView componentView;
    protected volatile ManagedReference reference;
 
@@ -63,33 +63,36 @@ public void init(final Endpoint endpoint) {
        componentViewName = (ServiceName) endpoint.getProperty(COMPONENT_VIEW_NAME);
    }
 
-   /**
-    * Gets endpoint container lazily.
-    *
-    * @return endpoint container
-    */
-   protected ComponentView getComponentView() {
-       // we need to check both, otherwise it is possible for
-       // componentView to be initialized before reference
-      if (componentView == null) {
-         synchronized(this) {
-            if (componentView == null) {
-               componentView = getMSCService(componentViewName, ComponentView.class);
-               if (componentView == null) {
-                  throw WSLogger.ROOT_LOGGER.cannotFindComponentView(componentViewName);
-               }
-               if (reference == null) {
-                  try {
-                      reference = componentView.createInstance();
-                  } catch (Exception e) {
-                      throw new RuntimeException(e);
-                  }
-               }
+    /**
+     * Gets endpoint container lazily.
+     *
+     * @return endpoint container
+     */
+    protected ComponentView getComponentView() {
+        ComponentView cv = componentView;
+        // we need to check both, otherwise it is possible for
+        // componentView to be initialized before reference
+        if (cv == null) {
+            synchronized (this) {
+                cv = componentView;
+                if (cv == null) {
+                    cv = getMSCService(componentViewName, ComponentView.class);
+                    if (cv == null) {
+                        throw WSLogger.ROOT_LOGGER.cannotFindComponentView(componentViewName);
+                    }
+                    if (reference == null) {
+                        try {
+                            reference = cv.createInstance();
+                        } catch (Exception e) {
+                            throw new RuntimeException(e);
+                        }
+                    }
+                    componentView = cv;
+                }
             }
-         }
-      }
-      return componentView;
-   }
+        }
+        return cv;
+    }
 
    /**
     * Invokes WS endpoint.
@@ -106,7 +109,8 @@ public void invoke(final Endpoint endpoint, final Invocation wsInvocation) throw
          final ComponentView componentView = getComponentView();
          Component component = componentView.getComponent();
          //in case of @FactoryType annotation we don't need to go into EE interceptors
-         if(wsInvocation.getInvocationContext().getProperty("forceTargetBean") != null) {
+         final boolean forceTargetBean = (wsInvocation.getInvocationContext().getProperty("forceTargetBean") != null);
+         if (forceTargetBean) {
              this.reference = new ManagedReference() {
                  public void release() {
                  }
@@ -126,7 +130,7 @@ public Object getInstance() {
          context.setParameters(wsInvocation.getArgs());
          context.putPrivateData(Component.class, component);
          context.putPrivateData(ComponentView.class, componentView);
-         if(wsInvocation.getInvocationContext().getProperty("forceTargetBean") != null) {
+         if(forceTargetBean) {
              context.putPrivateData(ManagedReference.class, reference);
          }
          // invoke method