pushing ItemGroupParent implementations outside to facilitate different implemenations.

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

@@ -126,7 +126,6 @@ import hudson.util.TextFile;
 import hudson.util.VersionNumber;
 import hudson.util.XStream2;
 import hudson.util.Service;
-import hudson.util.IOUtils;
 import hudson.views.DefaultMyViewsTabBar;
 import hudson.views.DefaultViewsTabBar;
 import hudson.views.MyViewsTabBar;
@@ -155,7 +154,6 @@ import org.jvnet.hudson.reactor.ReactorListener;
 import org.jvnet.hudson.reactor.TaskGraphBuilder.Handle;
 import org.kohsuke.args4j.Argument;
 import org.kohsuke.args4j.Option;
-import org.kohsuke.stapler.Ancestor;
 import org.kohsuke.stapler.HttpRedirect;
 import org.kohsuke.stapler.HttpResponse;
 import org.kohsuke.stapler.HttpResponses;
@@ -539,6 +537,21 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
      */
     private transient final AdjunctManager adjuncts;
 
+    /**
+     * Code that handles {@link ItemGroup} work.
+     */
+    private transient final ItemGroupMixIn itemGroupMixIn = new ItemGroupMixIn(this,this) {
+        @Override
+        protected void add(TopLevelItem item) {
+            items.put(item.getName(),item);
+        }
+
+        @Override
+        protected File getRootDirFor(String name) {
+            return Hudson.this.getRootDirFor(name);
+        }
+    };
+
     @CLIResolver
     public static Hudson getInstance() {
         return theInstance;
@@ -2085,25 +2098,8 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
      * @throws IllegalArgumentException
      *      if a project of the give name already exists.
      */
-    public synchronized TopLevelItem createProject( TopLevelItemDescriptor type, String name, boolean notify )
-            throws IOException {
-        if(items.containsKey(name))
-            throw new IllegalArgumentException("Project of the name "+name+" already exists");
-
-        TopLevelItem item;
-        try {
-            item = type.newInstance(name);
-        } catch (Exception e) {
-            throw new IllegalArgumentException(e);
-        }
-        item.onCreatedFromScratch();
-        item.save();
-        items.put(name,item);
-
-        if (notify)
-            ItemListener.fireOnCreated(item);
-
-        return item;
+    public synchronized TopLevelItem createProject( TopLevelItemDescriptor type, String name, boolean notify ) throws IOException {
+        return itemGroupMixIn.createProject(type,name,notify);
     }
 
     /**
@@ -2613,67 +2609,7 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
     }
 
     public synchronized Item doCreateItem( StaplerRequest req, StaplerResponse rsp ) throws IOException, ServletException {
-        checkPermission(Job.CREATE);
-
-        TopLevelItem result;
-
-        String requestContentType = req.getContentType();
-        if(requestContentType==null) {
-            rsp.sendError(HttpServletResponse.SC_BAD_REQUEST,"No Content-Type header set");
-            return null;
-        }
-        boolean isXmlSubmission = requestContentType.startsWith("application/xml") || requestContentType.startsWith("text/xml");
-
-        String name = req.getParameter("name");
-        if(name==null) {
-            rsp.sendError(HttpServletResponse.SC_BAD_REQUEST,"Query parameter 'name' is required");
-            return null;
-        }
-
-        name = checkJobName(name);
-
-        String mode = req.getParameter("mode");
-        if(mode!=null && mode.equals("copy")) {
-            String from = req.getParameter("from");
-            TopLevelItem src = getItem(from);
-            if(src==null) {
-                rsp.setStatus(SC_BAD_REQUEST);
-                if(Util.fixEmpty(from)==null)
-                    sendError("Specify which job to copy",req,rsp);
-                else
-                    sendError("No such job: "+from,req,rsp);
-                return null;
-            }
-
-            result = copy(src,name);
-        } else {
-            if(isXmlSubmission) {
-                result = createProjectFromXML(name, req.getInputStream());
-                rsp.setStatus(HttpServletResponse.SC_OK);
-                return result;
-            } else {
-                if(mode==null) {
-                    rsp.sendError(SC_BAD_REQUEST);
-                    return null;
-                }
-                // create empty job and redirect to the project config screen
-                result = createProject(Items.getDescriptor(mode), name);
-            }
-        }
-
-        // send the browser to the config page
-        // use View to trim view/{default-view} from URL if possible
-        String redirect = result.getUrl()+"configure";
-        List<Ancestor> ancestors = req.getAncestors();
-        for (int i = ancestors.size() - 1; i >= 0; i--) {
-            Object o = ancestors.get(i).getObject();
-            if (o instanceof View) {
-                redirect = req.getContextPath() + '/' + ((View)o).getUrl() + redirect;
-                break;
-            }
-        }
-        rsp.sendRedirect2(redirect);
-        return result;
+        return itemGroupMixIn.createTopLevelItem(req, rsp);
     }
 
     /**
@@ -2682,25 +2618,7 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
      * @since 1.319
      */
     public TopLevelItem createProjectFromXML(String name, InputStream xml) throws IOException {
-        // place it as config.xml
-        File configXml = Items.getConfigFile(getRootDirFor(name)).getFile();
-        configXml.getParentFile().mkdirs();
-        try {
-            IOUtils.copy(xml,configXml);
-
-            // load it
-            TopLevelItem result = (TopLevelItem)Items.load(this,configXml.getParentFile());
-            items.put(name,result);
-
-            ItemListener.fireOnCreated(result);
-            rebuildDependencyGraph();
-
-            return result;
-        } catch (IOException e) {
-            // if anything fails, delete the config file to avoid further confusion
-            Util.deleteRecursive(configXml.getParentFile());
-            throw e;
-        }
+        return itemGroupMixIn.createProjectFromXML(name,xml);
     }
 
     /**
@@ -2715,19 +2633,7 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
      */
     @SuppressWarnings({"unchecked"})
     public <T extends TopLevelItem> T copy(T src, String name) throws IOException {
-        T result = (T)createProject(src.getDescriptor(),name,false);
-
-        // copy config
-        Util.copyFile(Items.getConfigFile(src).getFile(),Items.getConfigFile(result).getFile());
-
-        // reload from the new config
-        result = (T)Items.load(this,result.getRootDir());
-        result.onCopiedFrom(src);
-        items.put(name,result);
-
-        ItemListener.fireOnCopied(src,result);
-
-        return result;
+        return itemGroupMixIn.copy(src,name);
     }
 
     // a little more convenient overloading that assumes the caller gives us the right type

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

 /*
  * The MIT License
  * 
- * Copyright (c) 2004-2009, Sun Microsystems, Inc., Kohsuke Kawaguchi
+ * Copyright (c) 2004-2009, Sun Microsystems, Inc., Kohsuke Kawaguchi, CloudBees, 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
@@ -23,21 +23,62 @@
  */
 package hudson.model;
 
+import hudson.Util;
+import hudson.model.listeners.ItemListener;
+import hudson.security.AccessControlled;
 import hudson.util.CopyOnWriteMap;
 import hudson.util.Function1;
+import hudson.util.IOUtils;
+import org.kohsuke.stapler.Ancestor;
+import org.kohsuke.stapler.StaplerRequest;
+import org.kohsuke.stapler.StaplerResponse;
 
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletResponse;
 import java.io.File;
 import java.io.FileFilter;
 import java.io.IOException;
+import java.io.InputStream;
+import java.util.List;
 import java.util.Map;
 
 /**
  * Defines a bunch of static methods to be used as a "mix-in" for {@link ItemGroup}
- * implementations.
+ * implementations. Not meant for a consumption from outside {@link ItemGroup}s.
  *
  * @author Kohsuke Kawaguchi
  */
-public class ItemGroupMixIn {
+public abstract class ItemGroupMixIn {
+    /**
+     * {@link ItemGroup} for which we are working.
+     */
+    private final ItemGroup parent;
+    private final AccessControlled acl;
+
+    protected ItemGroupMixIn(ItemGroup parent, AccessControlled acl) {
+        this.parent = parent;
+        this.acl = acl;
+    }
+
+    /*
+    * Callback methods to be implemented by the ItemGroup implementation.
+    */
+
+    /**
+     * Adds a newly created item to the parent.
+     */
+    protected abstract void add(TopLevelItem item);
+
+    /**
+     * Assigns the root directory for a prospective item.
+     */
+    protected abstract File getRootDirFor(String name);
+
+
+/*
+ * The rest is the methods that provide meat.
+ */
+
     /**
      * Loads all the child {@link Item}s.
      *
@@ -73,4 +114,145 @@ public class ItemGroupMixIn {
             return item.getName();
         }
     };
+
+    /**
+     * Creates a {@link TopLevelItem} from the submission of the '/lib/hudson/newFromList/formList'
+     */
+    public synchronized TopLevelItem createTopLevelItem( StaplerRequest req, StaplerResponse rsp ) throws IOException, ServletException {
+        acl.checkPermission(Job.CREATE);
+
+        TopLevelItem result;
+
+        String requestContentType = req.getContentType();
+        if(requestContentType==null)
+            throw new Failure("No Content-Type header set");
+
+        boolean isXmlSubmission = requestContentType.startsWith("application/xml") || requestContentType.startsWith("text/xml");
+
+        String name = req.getParameter("name");
+        if(name==null)
+            throw new Failure("Query parameter 'name' is required");
+
+        {// check if the name looks good
+            Hudson.checkGoodName(name);
+            name = name.trim();
+            if(parent.getItem(name)!=null)
+                throw new Failure(Messages.Hudson_JobAlreadyExists(name));
+        }
+
+        String mode = req.getParameter("mode");
+        if(mode!=null && mode.equals("copy")) {
+            String from = req.getParameter("from");
+            Item src = parent.getItem(from);
+            if(src==null) {
+                if(Util.fixEmpty(from)==null)
+                    throw new Failure("Specify which job to copy");
+                else
+                    throw new Failure("No such job: "+from);
+            }
+            if (!(src instanceof TopLevelItem)) {
+                throw new Failure(from+" cannot be copied");
+            }
+
+            result = copy((TopLevelItem) src,name);
+        } else {
+            if(isXmlSubmission) {
+                result = createProjectFromXML(name, req.getInputStream());
+                rsp.setStatus(HttpServletResponse.SC_OK);
+                return result;
+            } else {
+                if(mode==null)
+                    throw new Failure("No mode given");
+
+                // create empty job and redirect to the project config screen
+                result = createProject(Items.getDescriptor(mode), name, true);
+            }
+        }
+
+        // send the browser to the config page
+        // use View to trim view/{default-view} from URL if possible
+        String redirect = result.getUrl()+"configure";
+        List<Ancestor> ancestors = req.getAncestors();
+        for (int i = ancestors.size() - 1; i >= 0; i--) {
+            Object o = ancestors.get(i).getObject();
+            if (o instanceof View) {
+                redirect = req.getContextPath() + '/' + ((View)o).getUrl() + redirect;
+                break;
+            }
+        }
+        rsp.sendRedirect2(redirect);
+        return result;
+    }
+
+    /**
+     * Copies an existing {@link TopLevelItem} to a new name.
+     *
+     * The caller is responsible for calling {@link ItemListener#fireOnCopied(Item, Item)}. This method
+     * cannot do that because it doesn't know how to make the newly added item reachable from the parent.
+     */
+    @SuppressWarnings({"unchecked"})
+    public synchronized <T extends TopLevelItem> T copy(T src, String name) throws IOException {
+        acl.checkPermission(Job.CREATE);
+
+        T result = (T)createProject(src.getDescriptor(),name,false);
+
+        // copy config
+        Util.copyFile(Items.getConfigFile(src).getFile(),Items.getConfigFile(result).getFile());
+
+        // reload from the new config
+        result = (T)Items.load(parent,result.getRootDir());
+        result.onCopiedFrom(src);
+
+        add(result);
+        ItemListener.fireOnCopied(src,result);
+
+        return result;
+    }
+
+    public synchronized TopLevelItem createProjectFromXML(String name, InputStream xml) throws IOException {
+        acl.checkPermission(Job.CREATE);
+
+        // place it as config.xml
+        File configXml = Items.getConfigFile(getRootDirFor(name)).getFile();
+        configXml.getParentFile().mkdirs();
+        try {
+            IOUtils.copy(xml,configXml);
+
+            // load it
+            TopLevelItem result = (TopLevelItem)Items.load(parent,configXml.getParentFile());
+            add(result);
+
+            ItemListener.fireOnCreated(result);
+            Hudson.getInstance().rebuildDependencyGraph();
+
+            return result;
+        } catch (IOException e) {
+            // if anything fails, delete the config file to avoid further confusion
+            Util.deleteRecursive(configXml.getParentFile());
+            throw e;
+        }
+    }
+
+    public synchronized TopLevelItem createProject( TopLevelItemDescriptor type, String name, boolean notify )
+            throws IOException {
+        acl.checkPermission(Job.CREATE);
+
+        if(parent.getItem(name)!=null)
+            throw new IllegalArgumentException("Project of the name "+name+" already exists");
+
+        TopLevelItem item;
+        try {
+            item = type.newInstance(parent,name);
+        } catch (Exception e) {
+            throw new IllegalArgumentException(e);
+        }
+        item.onCreatedFromScratch();
+        item.save();
+        add(item);
+
+        if (notify)
+            ItemListener.fireOnCreated(item);
+
+        return item;
+    }
 }

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

@@ -24,15 +24,17 @@
 package hudson.model;
 
 import com.thoughtworks.xstream.XStream;
-import hudson.XmlFile;
 import hudson.DescriptorExtensionList;
 import hudson.Extension;
 import hudson.scm.RepositoryBrowser;
 import hudson.matrix.MatrixProject;
 import hudson.matrix.MatrixConfiguration;
+import hudson.XmlFile;
 import hudson.matrix.Axis;
-import hudson.util.XStream2;
+import hudson.matrix.MatrixConfiguration;
+import hudson.matrix.MatrixProject;
 import hudson.util.DescriptorList;
+import hudson.util.XStream2;
 
 import java.io.File;
 import java.io.IOException;

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

@@ -25,9 +25,12 @@ package hudson.model;
 
 import hudson.Extension;
 import hudson.ExtensionPoint;
+import hudson.matrix.MatrixConfiguration;
 
 /**
- * {@link Item} that can be directly displayed under {@link Hudson}. 
+ * {@link Item} that can be directly displayed under {@link Hudson} or other containers.
+ * Ones that don't need to be under specific parent (say, unlike {@link MatrixConfiguration}),
+ * and thus can be freely moved, copied, etc.
  *
  * <p>
  * To register a custom {@link TopLevelItem} class from a plugin, put {@link Extension} on your