Add static utility methods on container to add and remove beans.

Signed-off-by: Lachlan Roberts <lachlan@webtide.com>

Author: lachlan-roberts

jetty-util/src/main/java/org/eclipse/jetty/util/component/Container.java

@@ -152,6 +152,46 @@ default List<EventListener> getEventListeners()
         return Collections.unmodifiableList(new ArrayList<>(getBeans(EventListener.class)));
     }
 
+    /**
+     * A utility method to add a bean to a container.
+     * @param parent the parent container.
+     * @param child the child bean.
+     * @return true if the child was added as a bean, false if parent was not instance of {@link Container} or bean was already present.
+     */
+    static boolean addBean(Object parent, Object child)
+    {
+        if (parent instanceof Container)
+            return ((Container)parent).addBean(child);
+        return false;
+    }
+
+    /**
+     * A utility method to add a bean to a container.
+     * @param parent the parent container.
+     * @param child the child bean.
+     * @param managed whether to managed the lifecycle of the bean.
+     * @return true if the child was added as a bean, false if parent was not instance of {@link Container} or bean was already present.
+     */
+    static boolean addBean(Object parent, Object child, boolean managed)
+    {
+        if (parent instanceof Container)
+            return ((Container)parent).addBean(child, managed);
+        return false;
+    }
+
+    /**
+     * A utility method to remove a bean from a container.
+     * @param parent the parent container.
+     * @param child the child bean.
+     * @return true if parent was an instance of {@link Container} and the bean was removed.
+     */
+    static boolean removeBean(Object parent, Object child)
+    {
+        if (parent instanceof Container)
+            return ((Container)parent).removeBean(child);
+        return false;
+    }
+
     /**
      * A listener for Container events.
      * If an added bean implements this interface it will receive the events

jetty-util/src/main/java/org/eclipse/jetty/util/component/ContainerLifeCycle.java

@@ -474,9 +474,9 @@ public boolean addEventListener(EventListener listener)
                     if (listener instanceof InheritedListener && b.isManaged() && b._bean instanceof Container)
                     {
                         if (b._bean instanceof ContainerLifeCycle)
-                            ((ContainerLifeCycle)b._bean).addBean(listener, false);
+                            Container.addBean(b._bean, listener, false);
                         else
-                            ((Container)b._bean).addBean(listener);
+                            Container.addBean(b._bean, listener);
                     }
                 }
             }
@@ -499,8 +499,8 @@ public boolean removeEventListener(EventListener listener)
                 {
                     cl.beanRemoved(this, b._bean);
 
-                    if (listener instanceof InheritedListener && b.isManaged() && b._bean instanceof Container)
-                        ((Container)b._bean).removeBean(listener);
+                    if (listener instanceof InheritedListener && b.isManaged())
+                        Container.removeBean(b._bean, listener);
                 }
             }
             return true;
@@ -541,9 +541,9 @@ private void manage(Bean bean)
                     if (l instanceof InheritedListener)
                     {
                         if (bean._bean instanceof ContainerLifeCycle)
-                            ((ContainerLifeCycle)bean._bean).addBean(l, false);
+                            Container.addBean(bean._bean, l, false);
                         else
-                            ((Container)bean._bean).addBean(l);
+                            Container.addBean(bean._bean, l);
                     }
                 }
             }
@@ -579,7 +579,7 @@ private void unmanage(Bean bean)
                 for (Container.Listener l : _listeners)
                 {
                     if (l instanceof InheritedListener)
-                        ((Container)bean._bean).removeBean(l);
+                        Container.removeBean(bean._bean, l);
                 }
             }
             bean._managed = Managed.UNMANAGED;