Added an extension point for inserting actions across all projects without configuration.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@22262 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/Util.java

@@ -862,6 +862,10 @@ public class Util {
         return l!=null ? l : Collections.<T>emptySet();
     }
 
+    public static <T> Collection<T> fixNull(Collection<T> l) {
+        return l!=null ? l : Collections.<T>emptySet();
+    }
+
     /**
      * Cuts all the leading path portion and get just the file name.
      */

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

@@ -482,6 +482,9 @@ public abstract class AbstractProject<P extends AbstractProject<P,R>,R extends A
                 if(a!=null)
                     transientActions.add(a);
             }
+
+            for (TransientProjectActionFactory tpaf : TransientProjectActionFactory.all())
+                transientActions.addAll(Util.fixNull(tpaf.createFor(this))); // be defensive against null
         }
     }
 
@@ -814,6 +817,8 @@ public abstract class AbstractProject<P extends AbstractProject<P,R>,R extends A
      * Note that this method returns a read-only view of {@link Action}s.
      * {@link BuildStep}s and others who want to add a project action
      * should do so by implementing {@link BuildStep#getProjectAction(AbstractProject)}.
+     *
+     * @see TransientProjectActionFactory
      */
     @Override
     public synchronized List<Action> getActions() {

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

@@ -0,0 +1,70 @@
+/*
+ * 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.model;
+
+import hudson.Extension;
+import hudson.ExtensionList;
+import hudson.ExtensionPoint;
+import hudson.tasks.BuildStep;
+
+import java.util.Collection;
+
+/**
+ * Extension point for inserting transient {@link Action}s into {@link AbstractProject}s.
+ *
+ * <p>
+ * Actions of projects are primarily determined by {@link BuildStep}s that are associated by configurations,
+ * but sometimes it's convenient to be able to add actions across all or many projects, without being invoked
+ * through configuration. This extension point provides such a mechanism.
+ *
+ * Actions of {@link AbstractProject}s are transient &mdash; they will not be persisted, and each time Hudson starts
+ * or the configuration of the job changes, they'll be recreated. Therefore, to maintain persistent data
+ * per project, you'll need to do data serialization by yourself. Do so by storing a file
+ * under {@link AbstractProject#getRootDir()}.
+ *
+ * <p>
+ * To register your implementation, put {@link Extension} on your subtype.
+ *
+ * @author Kohsuke Kawaguchi
+ * @since 1.327
+ * @see Action
+ */
+public abstract class TransientProjectActionFactory implements ExtensionPoint {
+    /**
+     * Creates actions for the given project.
+     *
+     * @param target
+     *      The project for which the action objects are requested. Never null.
+     * @return
+     *      Can be empty but must not be null.
+     */
+    public abstract Collection<? extends Action> createFor(AbstractProject target);
+
+    /**
+     * Returns all the registered {@link TransientProjectActionFactory}s.
+     */
+    public static ExtensionList<TransientProjectActionFactory> all() {
+        return Hudson.getInstance().getExtensionList(TransientProjectActionFactory.class);
+    }
+}