updated Publisher to support auto-discovery.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@15683 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/DescriptorExtensionList.java

@@ -30,6 +30,8 @@ import hudson.model.ViewDescriptor;
 import hudson.model.Descriptor.FormException;
 import hudson.util.Memoizer;
 import hudson.slaves.NodeDescriptor;
+import hudson.tasks.Publisher;
+import hudson.tasks.Publisher.DescriptorExtensionListImpl;
 
 import java.util.List;
 import java.util.ArrayList;
@@ -58,13 +60,23 @@ import net.sf.json.JSONObject;
  *
  * @since 1.286
  */
-public final class DescriptorExtensionList<T extends Describable<T>, D extends Descriptor<T>> extends ExtensionList<D> {
+public class DescriptorExtensionList<T extends Describable<T>, D extends Descriptor<T>> extends ExtensionList<D> {
+    /**
+     * Creates a new instance.
+     */
+    public static <T extends Describable<T>,D extends Descriptor<T>>
+    DescriptorExtensionList<T,D> create(Hudson hudson, Class<T> describableType) {
+        if(describableType==Publisher.class)
+            return (DescriptorExtensionList)new DescriptorExtensionListImpl(hudson);
+        return new DescriptorExtensionList<T,D>(hudson,describableType);
+    }
+
     /**
      * Type of the {@link Describable} that this extension list retains.
      */
     private final Class<T> describableType;
 
-    public DescriptorExtensionList(Hudson hudson, Class<T> describableType) {
+    protected DescriptorExtensionList(Hudson hudson, Class<T> describableType) {
         super(hudson, (Class)Descriptor.class, legacyDescriptors.get(describableType));
         this.describableType = describableType;
     }

core/src/main/java/hudson/ExtensionList.java

@@ -35,7 +35,6 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Vector;
 import java.util.concurrent.CopyOnWriteArrayList;
-import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * Retains the known extension instances for the given type 'T'.
@@ -65,7 +64,8 @@ public class ExtensionList<T> extends AbstractList<T> {
     /**
      * Once discovered, extensions are retained here.
      */
-    private volatile CopyOnWriteArrayList<T> extensions;
+    @CopyOnWrite
+    private volatile List<T> extensions;
 
     /**
      * Place to store manually registered instances with the per-Hudson scope.
@@ -119,11 +119,14 @@ public class ExtensionList<T> extends AbstractList<T> {
      *      Prefer automatic registration.
      */
     @Override
-    public boolean add(T t) {
+    public synchronized boolean add(T t) {
         legacyInstances.add(t);
         // if we've already filled extensions, add it
-        if(extensions!=null)
-            extensions.add(t);
+        if(extensions!=null) {
+            List<T> r = new ArrayList<T>(extensions);
+            r.add(t);
+            extensions = sort(r);
+        }
         return true;
     }
 
@@ -149,7 +152,7 @@ public class ExtensionList<T> extends AbstractList<T> {
             if(extensions==null) {
                 List<T> r = load();
                 r.addAll(legacyInstances);
-                extensions = new CopyOnWriteArrayList<T>(r);
+                extensions = sort(r);
             }
             return extensions;
         }
@@ -165,6 +168,17 @@ public class ExtensionList<T> extends AbstractList<T> {
         return r;
     }
 
+    /**
+     * If the {@link ExtensionList} implementation requires sorting extensions,
+     * override this method to do so.
+     *
+     * <p>
+     * The implementation should copy a list, do a sort, and return the new instance.
+     */
+    protected List<T> sort(List<T> r) {
+        return r;
+    }
+
     public static <T> ExtensionList<T> create(Hudson hudson, Class<T> type) {
         if(type==ExtensionFinder.class)
             return new ExtensionList<T>(hudson,type) {

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

@@ -606,7 +606,7 @@ public class Functions {
     }
 
     public static List<Descriptor<Publisher>> getPublisherDescriptors(AbstractProject<?,?> project) {
-        return BuildStepDescriptor.filter(BuildStep.PUBLISHERS, project.getClass());
+        return BuildStepDescriptor.filter(Publisher.all(), project.getClass());
     }
 
     public static List<Descriptor<ComputerLauncher>> getComputerLauncherDescriptors() {

core/src/main/java/hudson/matrix/MatrixProject.java

@@ -536,7 +536,7 @@ public class MatrixProject extends AbstractProject<MatrixProject,MatrixBuild> im
 
         buildWrappers.rebuild(req, json, BuildWrappers.getFor(this));
         builders.rebuildHetero(req, json, Builder.all(), "builder");
-        publishers.rebuild(req, json, BuildStepDescriptor.filter(BuildStep.PUBLISHERS,this.getClass()));
+        publishers.rebuild(req, json, BuildStepDescriptor.filter(Publisher.all(),this.getClass()));
         updateTransientActions(); // to pick up transient actions from builder, publisher, etc.
 
         rebuildConfigurations();

core/src/main/java/hudson/maven/MavenModuleSet.java

@@ -604,7 +604,7 @@ public final class MavenModuleSet extends AbstractMavenProject<MavenModuleSet,Ma
         ignoreUpstremChanges = !json.has("triggerByDependency");
 
         reporters.rebuild(req,json,MavenReporters.getConfigurableList());
-        publishers.rebuild(req,json,BuildStepDescriptor.filter(BuildStep.PUBLISHERS,this.getClass()));
+        publishers.rebuild(req,json,BuildStepDescriptor.filter(Publisher.all(),this.getClass()));
         buildWrappers.rebuild(req,json,BuildWrappers.getFor(this));
 
         updateTransientActions(); // to pick up transient actions from builder, publisher, etc.

core/src/main/java/hudson/maven/RedeployPublisher.java

@@ -24,6 +24,7 @@
 package hudson.maven;
 
 import hudson.Launcher;
+import hudson.Extension;
 import hudson.maven.reporters.MavenAbstractArtifactRecord;
 import hudson.model.AbstractBuild;
 import hudson.model.AbstractProject;
@@ -31,6 +32,7 @@ import hudson.model.BuildListener;
 import hudson.model.Result;
 import hudson.tasks.BuildStepDescriptor;
 import hudson.tasks.Publisher;
+import hudson.tasks.Recorder;
 import net.sf.json.JSONObject;
 import org.apache.maven.artifact.deployer.ArtifactDeploymentException;
 import org.apache.maven.artifact.repository.ArtifactRepository;
@@ -50,7 +52,7 @@ import java.io.IOException;
  * @author Kohsuke Kawaguchi
  * @since 1.191
  */
-public class RedeployPublisher extends Publisher {
+public class RedeployPublisher extends Recorder {
     /**
      * Repository ID. This is matched up with <tt>~/.m2/settings.xml</tt> for authentication related information.
      */
@@ -115,16 +117,8 @@ public class RedeployPublisher extends Publisher {
         return build.getAction(MavenAbstractArtifactRecord.class);
     }
 
-    public BuildStepDescriptor<Publisher> getDescriptor() {
-        return DESCRIPTOR;
-    }
-
-    public static final DescriptorImpl DESCRIPTOR = new DescriptorImpl();
-
+    @Extension
     public static class DescriptorImpl extends BuildStepDescriptor<Publisher> {
-        private DescriptorImpl() {
-        }
-
         protected DescriptorImpl(Class<? extends Publisher> clazz) {
             super(clazz);
         }

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

@@ -286,7 +286,7 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
      */
     private transient final Memoizer<Class,DescriptorExtensionList> descriptorLists = new Memoizer<Class,DescriptorExtensionList>() {
         public DescriptorExtensionList compute(Class key) {
-            return new DescriptorExtensionList(Hudson.this,key);
+            return DescriptorExtensionList.create(Hudson.this,key);
         }
     };
 
@@ -654,7 +654,7 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
      * Gets the publisher descriptor by name. Primarily used for making them web-visible.
      */
     public Descriptor<Publisher> getPublisher(String shortClassName) {
-        return findDescriptor(shortClassName, BuildStep.PUBLISHERS);
+        return findDescriptor(shortClassName, Publisher.all());
     }
 
     /**
@@ -2027,7 +2027,7 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
             for( Descriptor<Builder> d : Builder.all() )
                 result &= configureDescriptor(req,json,d);
 
-            for( Descriptor<Publisher> d : BuildStep.PUBLISHERS )
+            for( Descriptor<Publisher> d : Publisher.all() )
                 result &= configureDescriptor(req,json,d);
 
             for( Descriptor<BuildWrapper> d : BuildWrapper.all() )

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

@@ -187,7 +187,7 @@ public abstract class Project<P extends Project<P,B>,B extends Build<P,B>>
 
         buildWrappers.rebuild(req,json, BuildWrappers.getFor(this));
         builders.rebuildHetero(req,json, Builder.all(), "builder");
-        publishers.rebuild(req, json, BuildStepDescriptor.filter(BuildStep.PUBLISHERS, this.getClass()));
+        publishers.rebuild(req, json, BuildStepDescriptor.filter(Publisher.all(), this.getClass()));
         updateTransientActions(); // to pick up transient actions from builder, publisher, etc.
     }
 

core/src/main/java/hudson/tasks/ArtifactArchiver.java

@@ -26,6 +26,7 @@ package hudson.tasks;
 import hudson.FilePath;
 import hudson.Launcher;
 import hudson.Util;
+import hudson.Extension;
 import hudson.maven.AbstractMavenProject;
 import hudson.model.AbstractBuild;
 import hudson.model.AbstractProject;
@@ -48,7 +49,7 @@ import net.sf.json.JSONObject;
  *
  * @author Kohsuke Kawaguchi
  */
-public class ArtifactArchiver extends Publisher {
+public class ArtifactArchiver extends Recorder {
 
     /**
      * Comma- or space-separated list of patterns of files/directories to be archived.
@@ -146,13 +147,7 @@ public class ArtifactArchiver extends Publisher {
         return true;
     }
 
-    public Descriptor<Publisher> getDescriptor() {
-        return DESCRIPTOR;
-    }
-
-
-    public static final Descriptor<Publisher> DESCRIPTOR = new DescriptorImpl();
-
+    @Extension
     public static class DescriptorImpl extends BuildStepDescriptor<Publisher> {
         public String getDisplayName() {
             return Messages.ArtifactArchiver_DisplayName();

core/src/main/java/hudson/tasks/BuildStep.java

@@ -25,6 +25,7 @@ package hudson.tasks;
 
 import hudson.Launcher;
 import hudson.Extension;
+import hudson.ExtensionList;
 import hudson.util.DescriptorList;
 import hudson.maven.RedeployPublisher;
 import hudson.model.AbstractBuild;
@@ -34,6 +35,7 @@ import hudson.model.Build;
 import hudson.model.BuildListener;
 import hudson.model.Descriptor;
 import hudson.model.Project;
+import hudson.model.Hudson;
 import hudson.tasks.junit.JUnitResultArchiver;
 import hudson.tasks.test.AggregatedTestResultPublisher;
 
@@ -41,6 +43,9 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.AbstractList;
+import java.util.Iterator;
+import java.util.WeakHashMap;
 
 /**
  * One step of the whole build process.
@@ -140,25 +145,32 @@ public interface BuildStep {
      * results, etc.
      *
      * @see PublisherList#addNotifier(Descriptor)
-     * @see PublisherList#addRecorder(Descriptor) 
+     * @see PublisherList#addRecorder(Descriptor)
+     *
+     * @deprecated as of 1.286.
+     *      Use {@link Publisher#all()} for read access, and use
+     *      {@link Extension} for registration.
      */
-    public static final PublisherList PUBLISHERS = new PublisherList(Descriptor.toList(
-        ArtifactArchiver.DESCRIPTOR,
-        Fingerprinter.DESCRIPTOR,
-        JavadocArchiver.DESCRIPTOR,
-        JUnitResultArchiver.DescriptorImpl.DESCRIPTOR,
-        AggregatedTestResultPublisher.DescriptorImpl.INSTANCE,
-        BuildTrigger.DESCRIPTOR,
-        RedeployPublisher.DESCRIPTOR,
-        Mailer.DESCRIPTOR
-    ));
+    public static final PublisherList PUBLISHERS = new PublisherList();
 
     /**
      * List of publisher descriptor.
      */
-    public static final class PublisherList extends ArrayList<Descriptor<Publisher>> {
-        public PublisherList(Collection<? extends Descriptor<Publisher>> c) {
-            super(c);
+    public static final class PublisherList extends AbstractList<Descriptor<Publisher>> {
+        /**
+         * {@link Descriptor}s are actually stored in here.
+         * Since {@link PublisherList} lives longer than {@link Hudson} we cannot directly use {@link ExtensionList}.
+         */
+        private final DescriptorList<Publisher> core = new DescriptorList<Publisher>(Publisher.class);
+
+        /**
+         * For descriptors that are manually registered, remember what kind it was since
+         * older plugins don't extend from neither {@link Recorder} nor {@link Notifier}.
+         */
+        /*package*/ static final WeakHashMap<Descriptor<Publisher>,Class<? extends Publisher>/*either Recorder.class or Notifier.class*/>
+                KIND = new WeakHashMap<Descriptor<Publisher>, Class<? extends Publisher>>();
+
+        private PublisherList() {
         }
 
         /**
@@ -172,7 +184,8 @@ public interface BuildStep {
          * @see #addRecorder(Descriptor)
          */
         public void addNotifier( Descriptor<Publisher> d ) {
-            add(d);
+            KIND.put(d,Notifier.class);
+            core.add(d);
         }
         
         /**
@@ -185,18 +198,31 @@ public interface BuildStep {
          * @see #addNotifier(Descriptor) 
          */
         public void addRecorder( Descriptor<Publisher> d ) {
-            int idx = super.indexOf(Mailer.DESCRIPTOR);
-            add(idx,d);
+            KIND.put(d,Recorder.class);
+            core.add(d);
         }
 
         @Override
         public boolean add(Descriptor<Publisher> d) {
-            return !contains(d) && super.add(d);
+            return !contains(d) && core.add(d);
         }
 
         @Override
         public void add(int index, Descriptor<Publisher> d) {
-            if(!contains(d)) super.add(index, d);
+            if(!contains(d)) core.add(d);
+        }
+
+        public Descriptor<Publisher> get(int index) {
+            return core.get(index);
+        }
+
+        public int size() {
+            return core.size();
+        }
+
+        @Override
+        public Iterator<Descriptor<Publisher>> iterator() {
+            return core.iterator();
         }
     }
 }

core/src/main/java/hudson/tasks/BuildTrigger.java

@@ -24,6 +24,7 @@
 package hudson.tasks;
 
 import hudson.Launcher;
+import hudson.Extension;
 import hudson.security.AccessControlled;
 import hudson.matrix.MatrixAggregatable;
 import hudson.matrix.MatrixAggregator;
@@ -33,7 +34,6 @@ import hudson.model.AbstractProject;
 import hudson.model.BuildListener;
 import hudson.model.DependecyDeclarer;
 import hudson.model.DependencyGraph;
-import hudson.model.Descriptor;
 import hudson.model.Hudson;
 import hudson.model.Item;
 import hudson.model.Items;
@@ -74,7 +74,7 @@ import java.util.logging.Logger;
  *
  * @author Kohsuke Kawaguchi
  */
-public class BuildTrigger extends Publisher implements DependecyDeclarer, MatrixAggregatable {
+public class BuildTrigger extends Recorder implements DependecyDeclarer, MatrixAggregatable {
 
     /**
      * Comma-separated list of other projects to be scheduled.
@@ -237,13 +237,7 @@ public class BuildTrigger extends Publisher implements DependecyDeclarer, Matrix
         return this;
     }
 
-    public Descriptor<Publisher> getDescriptor() {
-        return DESCRIPTOR;
-    }
-
-
-    public static final Descriptor<Publisher> DESCRIPTOR = new DescriptorImpl();
-
+    @Extension
     public static class DescriptorImpl extends BuildStepDescriptor<Publisher> {
         public DescriptorImpl() {
             Hudson.getInstance().getJobListeners().add(new ItemListener() {
@@ -251,8 +245,8 @@ public class BuildTrigger extends Publisher implements DependecyDeclarer, Matrix
                 public void onRenamed(Item item, String oldName, String newName) {
                     // update BuildTrigger of other projects that point to this object.
                     // can't we generalize this?
-                    for( Project p : Hudson.getInstance().getProjects() ) {
-                        BuildTrigger t = (BuildTrigger) p.getPublishers().get(BuildTrigger.DESCRIPTOR);
+                    for( Project<?,?> p : Hudson.getInstance().getProjects() ) {
+                        BuildTrigger t = p.getPublishersList().get(BuildTrigger.class);
                         if(t!=null) {
                             if(t.onJobRenamed(oldName,newName)) {
                                 try {

core/src/main/java/hudson/tasks/Builder.java

@@ -74,5 +74,4 @@ public abstract class Builder extends BuildStepCompatibilityLayer implements Bui
     public static DescriptorExtensionList<Builder,Descriptor<Builder>> all() {
         return Hudson.getInstance().getDescriptorList(Builder.class);
     }
-
 }

core/src/main/java/hudson/tasks/Fingerprinter.java

@@ -27,13 +27,13 @@ import hudson.FilePath;
 import hudson.FilePath.FileCallable;
 import hudson.Launcher;
 import hudson.Util;
+import hudson.Extension;
 import hudson.maven.AbstractMavenProject;
 import hudson.model.AbstractBuild;
 import hudson.model.AbstractProject;
 import hudson.model.Action;
 import hudson.model.Build;
 import hudson.model.BuildListener;
-import hudson.model.Descriptor;
 import hudson.model.Fingerprint;
 import hudson.model.Fingerprint.BuildPtr;
 import hudson.model.FingerprintMap;
@@ -67,7 +67,7 @@ import java.util.logging.Logger;
  *
  * @author Kohsuke Kawaguchi
  */
-public class Fingerprinter extends Publisher implements Serializable {
+public class Fingerprinter extends Recorder implements Serializable {
 
     /**
      * Comma-separated list of files/directories to be fingerprinted.
@@ -103,7 +103,7 @@ public class Fingerprinter extends Publisher implements Serializable {
                 record(build, listener, record, targets);
 
             if(recordBuildArtifacts && build instanceof Build) {
-                ArtifactArchiver aa = (ArtifactArchiver) ((Build<?,?>)build).getProject().getPublishers().get(ArtifactArchiver.DESCRIPTOR);
+                ArtifactArchiver aa = ((Build<?,?>)build).getProject().getPublishersList().get(ArtifactArchiver.class);
                 if(aa==null) {
                     // configuration error
                     listener.error(Messages.Fingerprinter_NoArchiving());
@@ -195,12 +195,7 @@ public class Fingerprinter extends Publisher implements Serializable {
         }
     }
 
-    public Descriptor<Publisher> getDescriptor() {
-        return DESCRIPTOR;
-    }
-
-    public static final Descriptor<Publisher> DESCRIPTOR = new DescriptorImpl();
-
+    @Extension
     public static class DescriptorImpl extends BuildStepDescriptor<Publisher> {
         public String getDisplayName() {
             return Messages.Fingerprinter_DisplayName();

core/src/main/java/hudson/tasks/JavadocArchiver.java

@@ -26,6 +26,7 @@ package hudson.tasks;
 import hudson.FilePath;
 import hudson.Launcher;
 import hudson.Util;
+import hudson.Extension;
 import hudson.maven.AbstractMavenProject;
 import hudson.model.*;
 import hudson.util.FormFieldValidator;
@@ -43,7 +44,7 @@ import java.io.IOException;
  *
  * @author Kohsuke Kawaguchi
  */
-public class JavadocArchiver extends Publisher {
+public class JavadocArchiver extends Recorder {
     /**
      * Path to the Javadoc directory in the workspace.
      */
@@ -115,12 +116,6 @@ public class JavadocArchiver extends Publisher {
         return new JavadocAction(project);
     }
 
-    public Descriptor<Publisher> getDescriptor() {
-        return DESCRIPTOR;
-    }
-
-    public static final Descriptor<Publisher> DESCRIPTOR = new DescriptorImpl();
-
     protected static abstract class BaseJavadocAction implements Action {
         public String getUrlName() {
             return "javadoc";
@@ -197,6 +192,7 @@ public class JavadocArchiver extends Publisher {
         }
     }
 
+    @Extension
     public static class DescriptorImpl extends BuildStepDescriptor<Publisher> {
         public String getDisplayName() {
             return Messages.JavadocArchiver_DisplayName();

core/src/main/java/hudson/tasks/Mailer.java

@@ -25,12 +25,11 @@ package hudson.tasks;
 
 import hudson.Launcher;
 import hudson.Functions;
+import hudson.Extension;
 import hudson.maven.AbstractMavenProject;
 import hudson.model.AbstractBuild;
 import hudson.model.AbstractProject;
-import hudson.model.Build;
 import hudson.model.BuildListener;
-import hudson.model.Descriptor;
 import hudson.model.User;
 import hudson.model.UserPropertyDescriptor;
 import hudson.util.FormFieldValidator;
@@ -66,7 +65,7 @@ import net.sf.json.JSONObject;
  *
  * @author Kohsuke Kawaguchi
  */
-public class Mailer extends Publisher {
+public class Mailer extends Notifier {
     protected static final Logger LOGGER = Logger.getLogger(Mailer.class.getName());
 
     /**
@@ -97,7 +96,7 @@ public class Mailer extends Publisher {
             /** Check whether a path (/-separated) will be archived. */
             @Override
             public boolean artifactMatches(String path, AbstractBuild<?,?> build) {
-                ArtifactArchiver aa = (ArtifactArchiver) build.getProject().getPublishersList().toMap().get(ArtifactArchiver.DESCRIPTOR);
+                ArtifactArchiver aa = build.getProject().getPublishersList().get(ArtifactArchiver.class);
                 if (aa == null) {
                     LOGGER.finer("No ArtifactArchiver found");
                     return false;
@@ -119,12 +118,7 @@ public class Mailer extends Publisher {
         }.execute(build,listener);
     }
 
-    public Descriptor<Publisher> getDescriptor() {
-        return DESCRIPTOR;
-    }
-
-    public static final DescriptorImpl DESCRIPTOR = new DescriptorImpl();
-
+    @Extension
     public static final class DescriptorImpl extends BuildStepDescriptor<Publisher> {
         /**
          * The default e-mail address suffix appended to the user name found from changelog,

core/src/main/java/hudson/tasks/Notifier.java

+/*
+ * The MIT License
+ *
+ * Copyright (c) 2004-2009, Sun Microsystems, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package hudson.tasks;
+
+import hudson.Extension;
+import hudson.ExtensionPoint;
+
+/**
+ * {@link BuildStep}s that run after the build is completed.
+ *
+ * <p>
+ * {@link Notifier} is a kind of {@link Publisher} that sends out the outcome of the builds to
+ * other systems and humans. This marking ensures that notifiers are run after the build result
+ * is set to its final values by other {@link Recorder}s.
+ *
+ * <p>
+ * To register a custom {@link Publisher} from a plugin,
+ * put {@link Extension} on your descriptor.
+ *
+ *
+ * @author Kohsuke Kawaguchi
+ * @since 1.286
+ * @see Recorder
+ */
+public abstract class Notifier extends Publisher implements ExtensionPoint {
+    public BuildStepDescriptor getDescriptor() {
+        return (BuildStepDescriptor)super.getDescriptor();
+    }
+}

core/src/main/java/hudson/tasks/Publisher.java

@@ -25,6 +25,8 @@ package hudson.tasks;
 
 import hudson.ExtensionPoint;
 import hudson.Launcher;
+import hudson.DescriptorExtensionList;
+import hudson.Extension;
 import hudson.maven.MavenReporter;
 import hudson.model.Action;
 import hudson.model.Build;
@@ -32,13 +34,20 @@ import hudson.model.BuildListener;
 import hudson.model.Describable;
 import hudson.model.Project;
 import hudson.model.AbstractBuild;
+import hudson.model.Descriptor;
+import hudson.model.Hudson;
+
+import java.util.List;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
 
 /**
  * {@link BuildStep}s that run after the build is completed.
  *
  * <p>
  * To register a custom {@link Publisher} from a plugin,
- * add it to {@link BuildStep#PUBLISHERS}.
+ * put {@link Extension} on your descriptor implementation.
  *
  * <p>
  * Starting 1.178, publishers are exposed to all kinds of different
@@ -55,7 +64,15 @@ import hudson.model.AbstractBuild;
  * @author Kohsuke Kawaguchi
  */
 public abstract class Publisher extends BuildStepCompatibilityLayer implements BuildStep, Describable<Publisher>, ExtensionPoint {
-//
+    /**
+     * @deprecated
+     *      Don't extend from {@link Publisher} directly. Instead, choose {@link Recorder} or {@link Notifier}
+     *      as your base class.
+     */
+    protected Publisher() {
+    }
+
+    //
 // these two methods need to remain to keep binary compatibility with plugins built with Hudson < 1.150
 //
     /**
@@ -99,4 +116,55 @@ public abstract class Publisher extends BuildStepCompatibilityLayer implements B
     public boolean needsToRunAfterFinalized() {
         return false;
     }
+
+    public Descriptor<Publisher> getDescriptor() {
+        return Hudson.getInstance().getDescriptor(getClass());
+    }
+
+    /**
+     * {@link Publisher} has a special sort semantics that requires a subtype.
+     *
+     * @see DescriptorExtensionList#create(Hudson, Class) 
+     */
+    public static final class DescriptorExtensionListImpl extends DescriptorExtensionList<Publisher,Descriptor<Publisher>>
+            implements Comparator<Descriptor<Publisher>> {
+        public DescriptorExtensionListImpl(Hudson hudson) {
+            super(hudson,Publisher.class);
+        }
+
+        @Override
+        protected List<Descriptor<Publisher>> sort(List<Descriptor<Publisher>> r) {
+            List<Descriptor<Publisher>> copy = new ArrayList<Descriptor<Publisher>>(r);
+            Collections.sort(copy,this);
+            return copy;
+        }
+
+        public int compare(Descriptor<Publisher> lhs, Descriptor<Publisher> rhs) {
+            return classify(lhs)-classify(rhs);
+        }
+
+        /**
+         * If recorder, return 0, if unknown return 1, if notifier returns 2.
+         * This is used as a sort key.
+         */
+        private int classify(Descriptor<Publisher> d) {
+            if(Recorder.class.isAssignableFrom(d.clazz))    return 0;
+            if(Notifier.class.isAssignableFrom(d.clazz))    return 2;
+
+            // for compatibility, if the descriptor is manually registered in a specific way, detect that.
+            Class<? extends Publisher> kind = PublisherList.KIND.get(d);
+            if(kind==Recorder.class)    return 0;
+            if(kind==Notifier.class)    return 2;
+
+            return 1;
+        }
+    }
+
+    /**
+     * Returns all the registered {@link Publisher} descriptors.
+     */
+    // for backward compatibility, the signature is not BuildStepDescriptor
+    public static DescriptorExtensionList<Publisher,Descriptor<Publisher>> all() {
+        return Hudson.getInstance().getDescriptorList(Publisher.class);
+    }
 }

core/src/main/java/hudson/tasks/Recorder.java

+/*
+ * The MIT License
+ *
+ * Copyright (c) 2004-2009, Sun Microsystems, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package hudson.tasks;
+
+import hudson.Extension;
+import hudson.ExtensionPoint;
+
+/**
+ * {@link BuildStep}s that run after the build is completed.
+ *
+ * <p>
+ * {@link Recorder} is a kind of {@link Publisher} that collects statistics from the build,
+ * and can mark builds as untable/failure. This marking ensures that builds are marked accordingly
+ * before notifications are sent via {@link Notifier}s. Otherwise, if the build is marked failed
+ * after some notifications are sent, inconsistency ensues.
+ *
+ * <p>
+ * To register a custom {@link Publisher} from a plugin,
+ * put {@link Extension} on your descriptor.
+ *
+ *
+ * @author Kohsuke Kawaguchi
+ * @since 1.286
+ * @see Notifier
+ */
+public abstract class Recorder extends Publisher implements ExtensionPoint {
+    public BuildStepDescriptor getDescriptor() {
+        return (BuildStepDescriptor)super.getDescriptor();
+    }
+}

core/src/main/java/hudson/tasks/junit/JUnitResultArchiver.java

@@ -26,6 +26,7 @@ package hudson.tasks.junit;
 import hudson.FilePath.FileCallable;
 import hudson.Launcher;
 import hudson.Util;
+import hudson.Extension;
 import hudson.maven.AbstractMavenProject;
 import hudson.matrix.MatrixAggregatable;
 import hudson.matrix.MatrixAggregator;
@@ -34,6 +35,7 @@ import hudson.model.*;
 import hudson.remoting.VirtualChannel;
 import hudson.tasks.Publisher;
 import hudson.tasks.BuildStepDescriptor;
+import hudson.tasks.Recorder;
 import hudson.tasks.test.TestResultAggregator;
 import hudson.tasks.test.TestResultProjectAction;
 import hudson.util.FormFieldValidator;
@@ -53,7 +55,7 @@ import java.io.Serializable;
  *
  * @author Kohsuke Kawaguchi
  */
-public class JUnitResultArchiver extends Publisher implements Serializable, MatrixAggregatable {
+public class JUnitResultArchiver extends Recorder implements Serializable, MatrixAggregatable {
 
     /**
      * {@link FileSet} "includes" string, like "foo/bar/*.xml"
@@ -130,15 +132,10 @@ public class JUnitResultArchiver extends Publisher implements Serializable, Matr
         return new TestResultAggregator(build,launcher,listener);
     }
 
-    public Descriptor<Publisher> getDescriptor() {
-        return DescriptorImpl.DESCRIPTOR;
-    }
-
     private static final long serialVersionUID = 1L;
 
+    @Extension
     public static class DescriptorImpl extends BuildStepDescriptor<Publisher> {
-        public static final Descriptor<Publisher> DESCRIPTOR = new DescriptorImpl();
-
         public String getDisplayName() {
             return Messages.JUnitResultArchiver_DisplayName();
         }

core/src/main/java/hudson/tasks/test/AggregatedTestResultPublisher.java

@@ -25,6 +25,7 @@ package hudson.tasks.test;
 
 import hudson.Launcher;
 import hudson.Util;
+import hudson.Extension;
 import hudson.model.AbstractBuild;
 import hudson.model.AbstractProject;
 import hudson.model.BuildListener;
@@ -37,6 +38,7 @@ import hudson.model.TaskListener;
 import hudson.model.listeners.RunListener;
 import hudson.tasks.BuildStepDescriptor;
 import hudson.tasks.Publisher;
+import hudson.tasks.Recorder;
 import hudson.util.FormFieldValidator;
 import net.sf.json.JSONObject;
 import org.kohsuke.stapler.QueryParameter;
@@ -57,7 +59,7 @@ import java.util.List;
  *
  * @author Kohsuke Kawaguchi
  */
-public class AggregatedTestResultPublisher extends Publisher {
+public class AggregatedTestResultPublisher extends Recorder {
     /**
      * Jobs to aggregate. Camma separated.
      * Null if triggering downstreams.
@@ -74,10 +76,6 @@ public class AggregatedTestResultPublisher extends Publisher {
         return true;
     }
 
-    public DescriptorImpl getDescriptor() {
-        return DescriptorImpl.INSTANCE;
-    }
-
     /**
      * Action that serves the aggregated record.
      *
@@ -232,6 +230,7 @@ public class AggregatedTestResultPublisher extends Publisher {
         }
     }
 
+    @Extension
     public static final class DescriptorImpl extends BuildStepDescriptor<Publisher> {
         public boolean isApplicable(Class<? extends AbstractProject> jobType) {
             return true;    // for all types
@@ -268,8 +267,6 @@ public class AggregatedTestResultPublisher extends Publisher {
             else
                 return new AggregatedTestResultPublisher(s.getString("jobs"));
         }
-
-        public static final DescriptorImpl INSTANCE = new DescriptorImpl();
     }
 
 }

test/src/main/java/org/jvnet/hudson/test/HudsonTestCase.java

@@ -49,6 +49,7 @@ import hudson.slaves.RetentionStrategy;
 import hudson.tasks.BuildStep;
 import hudson.tasks.Mailer;
 import hudson.tasks.Maven;
+import hudson.tasks.Publisher;
 import hudson.tasks.Maven.MavenInstallation;
 import hudson.util.ProcessTreeKiller;
 import hudson.util.StreamTaskListener;
@@ -201,11 +202,6 @@ public abstract class HudsonTestCase extends TestCase {
         for (LenientRunnable r : tearDowns)
             r.run();
 
-        // TODO: avoid relying on singletons and switch to some DI container.
-        // In the mean time, discard descriptors created during this exercise.
-        // without this, plugins loaded in the tests will be left and interferes with the later tests.
-        cleanUpDescriptors(BuildStep.PUBLISHERS);
-
         hudson.cleanUp();
         env.dispose();
     }