updated PageDecorator to support auto discovery

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@15674 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/Functions.java

@@ -1037,7 +1037,7 @@ public class Functions {
      * Gets all the {@link PageDecorator}s.
      */
     public static List<PageDecorator> getPageDecorators() {
-        return (List)PageDecorator.ALL;
+        return PageDecorator.all();
     }
     
     public static DescriptorList<Cloud> getCloudDescriptors() {

core/src/main/java/hudson/model/Hudson.java

@@ -536,7 +536,6 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
             l.onLoaded();
 
         WindowsInstallerLink.registerIfApplicable();
-        UsageStatistics.register();
         LoadStatistics.register();
         NodeProvisioner.launch();
     }
@@ -2043,7 +2042,7 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
             for( JobPropertyDescriptor d : JobPropertyDescriptor.all() )
                 result &= configureDescriptor(req,json,d);
 
-            for( PageDecorator d : PageDecorator.ALL )
+            for( PageDecorator d : PageDecorator.all() )
                 result &= configureDescriptor(req,json,d);
 
             for( JSONObject o : StructuredForm.toList(json,"plugin"))

core/src/main/java/hudson/model/PageDecorator.java

@@ -25,9 +25,11 @@ package hudson.model;
 
 import hudson.ExtensionPoint;
 import hudson.Plugin;
+import hudson.ExtensionListView;
+import hudson.DescriptorExtensionList;
+import hudson.Extension;
 
 import java.util.List;
-import java.util.concurrent.CopyOnWriteArrayList;
 
 /**
  * Participates in the rendering of HTML pages for all pages of Hudson.
@@ -42,8 +44,8 @@ import java.util.concurrent.CopyOnWriteArrayList;
  *
  * <h2>Life-cycle</h2>
  * <p>
- * Instances of this class is singleton. {@link Plugin}s that contribute this extension point
- * should instantiate a new decorator and add it to the {@link #ALL} list in {@link Plugin#start()}. 
+ * {@link Plugin}s that contribute this extension point
+ * should implement a new decorator and put {@link Extension} on the class.
  *
  * <h2>Associated Views</h2>
  * <h4>global.jelly</h4>
@@ -74,15 +76,9 @@ public abstract class PageDecorator extends Descriptor<PageDecorator> implements
         super(yourClass);
     }
 
-    /**
-     * Infers the type of the corresponding {@link Describable} from the outer class.
-     * This version works when you follow the common convention, where a descriptor
-     * is written as the static nested class of the describable class.
-     *
-     * @since 1.278
-     */
-    protected PageDecorator() {
-    }
+// this will never work because Descriptor and Describable are the same thing.
+//    protected PageDecorator() {
+//    }
 
     public final Descriptor<PageDecorator> getDescriptor() {
         return this;
@@ -98,6 +94,15 @@ public abstract class PageDecorator extends Descriptor<PageDecorator> implements
 
     /**
      * All the registered instances.
+     * @deprecated as of 1.286
+     *      Use {@link #all()} for read access, and use {@link Extension} for registration.
      */
-    public static final List<PageDecorator> ALL = new CopyOnWriteArrayList<PageDecorator>();
+    public static final List<PageDecorator> ALL = ExtensionListView.createList(PageDecorator.class);
+
+    /**
+     * Returns all the registered {@link PageDecorator} descriptors.
+     */
+    public static DescriptorExtensionList<PageDecorator,PageDecorator> all() {
+        return Hudson.getInstance().getDescriptorList(PageDecorator.class);
+    }
 }

core/src/main/java/hudson/model/UpdateCenter.java

@@ -894,16 +894,13 @@ public class UpdateCenter extends AbstractModelObject {
     /**
      * Adds the update center data retriever to HTML.
      */
+    @Extension
     public static class PageDecoratorImpl extends PageDecorator {
         public PageDecoratorImpl() {
             super(PageDecoratorImpl.class);
         }
     }
 
-    static {
-        PageDecorator.ALL.add(new PageDecoratorImpl());
-    }
-
     /**
      * Sequence number generator.
      */

core/src/main/java/hudson/model/UsageStatistics.java

@@ -26,6 +26,7 @@ package hudson.model;
 import com.trilead.ssh2.crypto.Base64;
 import hudson.PluginWrapper;
 import hudson.Util;
+import hudson.Extension;
 import hudson.node_monitors.ArchitectureMonitor.DescriptorImpl;
 import static hudson.util.TimeUnit2.DAYS;
 import net.sf.json.JSONObject;
@@ -55,6 +56,7 @@ import java.util.zip.GZIPOutputStream;
 /**
  * @author Kohsuke Kawaguchi
  */
+@Extension
 public class UsageStatistics extends PageDecorator {
     private final String keyImage;
 
@@ -81,16 +83,6 @@ public class UsageStatistics extends PageDecorator {
         load();
     }
 
-    // register the instance
-    static {
-        PageDecorator.ALL.add(new UsageStatistics());
-    }
-
-    /**
-     * No-op, but calling this method makes sure that the static initializer is run.
-     */
-    static void register() {}
-
     /**
      * Returns true if it's time for us to check for new version.
      */