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 = Writing POV-Ray Support for NetBeans IX—Build Support
 :jbake-type: platform_tutorial
 :jbake-tags: tutorials
 :jbake-status: published
 :syntax: true
 :source-highlighter: pygments
 :toc: left
 :toc-title:
 :icons: font
 :experimental:
 :description: Writing POV-Ray Support for NetBeans IX—Build Support - Apache NetBeans
 :keywords: Apache NetBeans Platform, Platform Tutorials, Writing POV-Ray Support for NetBeans IX—Build Support

 This is a continuation of the tutorial for building a POV-Ray rendering application on the NetBeans Platform. If you have not read the  link:nbm-povray-1.html[first],  link:nbm-povray-2.html[second],  link:nbm-povray-3.html[third],  link:nbm-povray-4.html[fourth],  link:nbm-povray-5.html[fifth]  link:nbm-povray-6.html[sixth],  link:nbm-povray-7.html[seventh], and  link:nbm-povray-8.html[eighth] parts of this tutorial, you may want to start there.


 == Project Action Support

 You may recall that early on, when we were writing `PovrayProject`, we stubbed out the implementation of `PovrayProject.ActionsProviderImpl`—so in fact the build, clean and run actions are all disabled when a POV-Ray project is active. We should quickly implement them.

 Open `PovrayProject` in the code editor, and implement the methods of `ActionProviderImpl` as follows:


 [source,java]
 ----

 private final class ActionProviderImpl implements ActionProvider {

     @Override
     public String[] getSupportedActions() {
         return new String[]{
                     ActionProvider.COMMAND_BUILD,
                     ActionProvider.COMMAND_CLEAN,
                     ActionProvider.COMMAND_COMPILE_SINGLE
         };
     }

     @Override
     public void invokeAction(String string, Lookup lookup) throws IllegalArgumentException {
         int idx = Arrays.asList(getSupportedActions()).indexOf(string);
         switch (idx) {
             case 0: //build
                 final RendererService ren = (RendererService) getLookup().lookup(RendererService.class);
                 RequestProcessor.getDefault().post(new Runnable() {
                     @Override
                     public void run() {
                         FileObject image = ren.render();
                         //If we succeeded, try to open the image
                         if (image != null) {
                             DataObject dob;
                             try {
                                 dob = DataObject.find(image);
                                 OpenCookie open = (OpenCookie) dob.getNodeDelegate().getLookup().lookup(OpenCookie.class);
                                 if (open != null) {
                                     open.open();
                                 }
                             } catch (DataObjectNotFoundException ex) {
                                 Exceptions.printStackTrace(ex);
                             }
                         }
                     }
                 });
                 break;
             case 1: //clean
                 FileObject fob = getImagesFolder(false);
                 if (fob != null) {
                     DataFolder fld = DataFolder.findFolder(fob);
                     for (Enumeration en = fld.children(); en.hasMoreElements();) {
                         DataObject ob = (DataObject) en.nextElement();
                         try {
                             ob.delete();
                         } catch (IOException ioe) {
                             Exceptions.printStackTrace(ioe);
                         }
                     }
                 }
                 break;
             case 2: //compile-single
                 final DataObject ob = (DataObject) lookup.lookup(DataObject.class);
                 if (ob != null) {
                     final RendererService ren1 = (RendererService) getLookup().lookup(RendererService.class);
                     RequestProcessor.getDefault().post(new Runnable() {
                         @Override
                         public void run() {
                             if (ob.isValid()) { //Could theoretically change before we run
                                 ren1.render(ob.getPrimaryFile());
                             }
                         }
                     });
                 }
                 break;
             default:
                 throw new IllegalArgumentException(string);
         }
     }

     @Override
     public boolean isActionEnabled(String string, Lookup lookup) throws IllegalArgumentException {
         int idx = Arrays.asList(getSupportedActions()).indexOf(string);
         boolean result;
         switch (idx) {
             case 0: //build
                 result = true;
                 break;
             case 1: //clean
                 result = getImagesFolder(false) != null
                         &amp;&amp; getImagesFolder(false).getChildren().length > 0;
                 break;
             case 2: //compile-single
                 DataObject ob = (DataObject) lookup.lookup(DataObject.class);
                 if (ob != null) {
                     FileObject file = ob.getPrimaryFile();
                     result = "text/x-povray".equals(file.getMIMEType());
                 } else {
                     result = false;
                 }
                 break;
             default:
                 result = false;
         }
         return result;
     }

 }
 ----


 == Ensuring There Is A Main File

 We now have handling implemented for all of the standard project actions that make sense for a POV-Ray project. Now, if you've been following very carefully, you may have noticed that there is one bug we need to fix: `isActionEnabled()` will always return true for build. But we implemented the following code in `Povray.getFileToRender()`:


 [source,java]
 ----

 render = provider.getMainFile();
 if (render == null) {
     ProjectInformation info = (ProjectInformation) proj.getLookup().lookup(ProjectInformation.class);
     //XXX let the user choose
     throw new IOException(NbBundle.getMessage(Povray.class, "MSG_NoMainFile", info.getDisplayName()));
 }
 ----

 So if there is no main file set for a project, the build action will be enabled, but if it is invoked, it will throw an exception! The simple choice would be to test if there is a main file, and if not, disable the build action—but this would be rather non-intuitive to the user who might not be able to figure out what is wrong with the project. And we would miss an opportunity to explore the Explorer &amp; Property Sheet API, together with the Dialogs APIs!

 So instead, we will post a dialog which will allow the user to choose which file should be the main file, if none is set when build is called:


 [start=1]
 1. On the Povray Project module, following the procedure outlined in previous sections of this tutorial, add a module dependency on the Explorer &amp; Property Sheet API.

 [start=2]
 1. Right-click the `org.netbeans.examples.modules.povproject` package and chose New > Other > Swing GUI Forms > JPanel Form. Click Next. Name The JPanel "MainFileChooser" and click Finish. The GUI Designer (Matisse) will open.

 [start=3]
 1. In the Palette (Ctrl-Shift-8), click the item for `JLabel` and drag it to the top of the `JPanel`. Drag the right-hand edge of the `JLabel` to the right edge of the `JPanel` so that the `JLabel` will resize automatically at runtime.

 [start=4]
 1.
 In the Palette, click the item for `JScrollPane` and drag it to the `JPanel` below the `JLabel`. Drag the bottom right corner of the `JScrollPane` down and to the right until the bottom and right edge alignment guidelines appear. The result should look like this:


 image::images/povray_71_ch9_pic1.png[]


 [start=5]
 1. Make sure the Properties window (Ctrl-Shift-7) is open. Select the `JLabel` and and then click the [...] button for its `text` property in the Properties window. A custom editor will open:


 image::images/povray_71_ch9_pic2.png[]


 [start=6]
 1. Change the drop-down at the top of the dialog to "Custom code", as shown below, and then type  ``Bundle.LBL_ChooseMainFile()`` :


 image::images/povray_71_ch9_pic3.png[]

 Click OK. Now add this annotation above the class signature:

 *@NbBundle.Messages("LBL_ChooseMainFile=Select Main File")*

 [source,java]
 ----

 public class MainFileChooser extends javax.swing.JPanel {
 ----

 Save the file. Now the annotation is converted to a String constant in a  ``Bundle``  class and the reference to this class in the  ``initComponents``  block should not show an error anymore.


 [start=7]
 1. Edit the signature of the class so that it implements the interface `ExplorerManager.Provider`:

 [source,java]
 ----

 public class MainFileChooser extends javax.swing.JPanel implements ExplorerManager.Provider {
 ----


 [start=8]
 1. Add the following code to implement `ExplorerManager.Provider`:

 [source,java]
 ----

 private final ExplorerManager mgr = new ExplorerManager();

 public ExplorerManager getExplorerManager() {
     return mgr;
 }
 ----


 [start=9]
 1. Modify the constructor so it reads as follows:


 [source,java]
 ----

 public MainFileChooser(PovrayProject proj) {

     initComponents();

     setLayout(new BorderLayout());

     LogicalViewProvider logicalView = (LogicalViewProvider) proj.getLookup().lookup(LogicalViewProvider.class);

     Node projectNode = logicalView.createLogicalView();

     mgr.setRootContext(new FilterNode(projectNode, new ProjectFilterChildren(projectNode)));

     BeanTreeView btv = new BeanTreeView();

     jScrollPane1.setViewportView(btv);

     btv.setPopupAllowed(false);

     btv.setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);

     add(btv, BorderLayout.CENTER);

 }
 ----

 The `BeanTreeView` we are showing is a UI class from the Explorer API—in fact, it is the very same component that you see in the Projects, Files, Runtime and Favorites tabs in the NetBeans IDE.

 What it will do is, when it is added to a component, search through the hierarchy of parent components until it finds one that implements `ExplorerManager.Provider`. That component's `ExplorerManager` will then become the place where the tree view gets its root node to display, and will be what it notifies when the selection changes.

 NOTE:  An error mark will remain for `ProjectFilterNode` because we have not yet written it.


 [start=10]
 1. Now we need to implement `ProjectFilterNode`. The Nodes API contains a class, `FilterNode`, which makes it possible to take one `Node`, and create another `Node` which "filters" the original `Node`—providing different children, actions, properties or whatever it chooses to.

 In our case, we want a `FilterNode` that will filter out any files that do not have the MIME type `text/x-povray`—so that, if the user has a text file or an image file or such in their project, they cannot set that to be the main file and try to pass it to POV-Ray.

 We don't actually need to implement `FilterNode`, we simply need to provide an alternate `Children` object which filters out files we don't want. Implement this as a nested class inside `MainFileChooser`:


 [source,java]
 ----

 private static final class ProjectFilterChildren extends FilterNode.Children {

     ProjectFilterChildren(Node projectNode) {
 	super(projectNode);
     }

     @Override
     protected Node[] createNodes(Node object) {
 	Node origChild = (Node) object;
 	DataObject dob = (DataObject) origChild.getLookup().lookup(DataObject.class);
 	if (dob != null) {
 	    FileObject fob = dob.getPrimaryFile();
 	    if ("text/x-povray".equals(fob.getMIMEType())) {
 		return super.createNodes(object);
 	    } else if (dob instanceof DataFolder) {
 		//Allow child folders of the scenes/ dir
 		return new Node[]{
 			    new FilterNode(origChild,
 			    new ProjectFilterChildren(origChild))
 			};
 	    }
 	}
 	//Don't create any nodes for non-povray files
 	return new Node[0];
     }

 }
 ----


 [start=11]
 1. Now we just need some code to use this panel. That code will go in `RenderServiceImpl`, before we call `Povray.render()`. Reimplement the no-argument version of the `render()` method as follows:


 [source,java]
 ----

 @Override
 public FileObject render() {
     MainFileProvider mfp = (MainFileProvider) proj.getLookup().lookup(MainFileProvider.class);
     assert mfp != null;
     if (mfp.getMainFile() == null) {
 	showChooseMainFileDlg(mfp);
     }
     if (mfp.getMainFile() != null) {
 	return render(null);
     } else {
 	return null;
     }
 }
 ----


 [start=12]
 1. Now we need to implement the method we are calling above, `showChooseMainFileDlg()`. This is the method which will ask the user to pick a main file. It will use the Dialogs API to show a dialog containing an instance of `MainFileChooser`, and enable the OK button once a file is selected. If the user selects a POV-Ray file, it will be stored in `MainFileProvider`, and so it will be non-null when we return to the `render()` method, and so `render()` will proceed:


 [source,java]
 ----

 @NbBundle.Messages("TTL_ChooseMainFile=Choose Main File")
 private void showChooseMainFileDlg(final MainFileProvider mfp) {

     final MainFileChooser chooser = new MainFileChooser(proj);

     String title = Bundle.TTL_ChooseMainFile();

     //Create a simple dialog descriptor describing what kind of dialog
     //we want and its title and contents
     final DialogDescriptor desc = new DialogDescriptor(chooser, title);

     //The OK button should be disabled initially
     desc.setValid(false);

     //Create a property change listener.  It will listen on the selection
     //in our MainFileChooser, and enable the OK button if an appropriate
     //node is selected:
     PropertyChangeListener pcl = new PropertyChangeListener() {
 	@Override
 	public void propertyChange(PropertyChangeEvent pce) {
 	    String propName = pce.getPropertyName();
 	    if (ExplorerManager.PROP_SELECTED_NODES.equals(propName)) {
 		Node[] n = (Node[]) pce.getNewValue();
 		boolean valid = n.length == 1;
 		if (valid) {
 		    DataObject ob = (DataObject) n[0].getLookup().lookup(DataObject.class);
 		    valid = ob != null;
 		    if (valid) {
 			FileObject selectedFile = ob.getPrimaryFile();
 			String mimeType = selectedFile.getMIMEType();
 			valid = "text/x-povray".equals(mimeType);
 		    }
 		}
 		desc.setValid(valid);
 	    }
 	}
     };
     chooser.getExplorerManager().addPropertyChangeListener(pcl);

     //Show the dialog—dialogResult will be OK or Cancel
     Object dialogResult = DialogDisplayer.getDefault().notify(desc);

     //If the user clicked OK, try to set the main file
     //from the selection
     if (DialogDescriptor.OK_OPTION.equals(dialogResult)) {

 	//Get the selected Node
 	Node[] n = chooser.getExplorerManager().getSelectedNodes();

 	//If it's > 1, explorer is broken—we set
 	//single selection mode
 	assert n.length <= 1;
 	DataObject ob = (DataObject) n[0].getLookup().lookup(
 		DataObject.class);

 	//Get the file from the data object
 	FileObject selectedFile = ob.getPrimaryFile();

 	//And save it as the main file
 	mfp.setMainFile(selectedFile);

     }

 }
 ----


 == Extending the Project Popup Menu

 Right now, if you run the application and open a new POV-Ray project and right-click on it, there are no render or clean actions. The first thing we can do is improve the popup menu for POV-Ray projects—we need to add a couple of menu items to those already returned.


 [start=1]
 1. Open `PovrayLogicalView` in the editor, and find the inner `ScenesNode` class.

 [start=2]
 1.
 Override `getActions()` as follows:


 [source,java]
 ----

 @NbBundle.Messages({
     "LBL_Build=Render Project",
     "LBL_Clean=Clean Project"
 })
 @Override
 public Action[] getActions(boolean popup) {
     Action[] result = new Action[]{
 	new ProjectAction(ActionProvider.COMMAND_BUILD, Bundle.LBL_Build(), project),
 	new ProjectAction(ActionProvider.COMMAND_CLEAN, Bundle.LBL_Clean(), project),
 	new OtherProjectAction(project, false),
 	SystemAction.get(NewTemplateAction.class),
 	SystemAction.get(FileSystemAction.class),
 	new OtherProjectAction(project, true),
     };
     return result;
 }
 ----

 This gives us two classes to implement—`ProjectAction` and `OtherProjectAction`. The former will simply be an action class which delegates to the action provider of the project, and the other will use the `OpenProjects` class from the Project UI API to close the project.


 [start=3]
 1. Implement `ProjectAction` as follows:


 [source,java]
 ----

 private static class ProjectAction extends AbstractAction {

     private final PovrayProject project;
     private final String command;

     public ProjectAction(String cmd, String displayName, PovrayProject prj) {
 	this.project = prj;
 	putValue(NAME, displayName);
 	this.command = cmd;
     }

     @Override
     public void actionPerformed(ActionEvent actionEvent) {
 	ActionProvider prov = (ActionProvider) project.getLookup().lookup(ActionProvider.class);
 	prov.invokeAction(command, null);
     }

     @Override
     public boolean isEnabled() {
 	ActionProvider prov = (ActionProvider) project.getLookup().lookup(ActionProvider.class);
 	return prov.isActionEnabled(command, null);
     }

 }
 ----


 [start=4]
 1. Then implement the brilliantly named `OtherProjectAction` this way, also as a nested class inside PovrayLogicalView. What we're doing here is saving the overhead of one more class to do something simple, and writing one action that either closes the project or makes it the main project, depending on a flag. While not beautiful, it is short enough to be readable—and additional classes do come with a memory penalty, so for trivial things, this approach is not necessarily a bad idea—as long as the result is readable:


 [source,java]
 ----

 @NbBundle.Messages({
     "LBL_CloseProject=Close Project",
     "LBL_SetMainProject=Set Main Project"
 })
 private static class OtherProjectAction extends AbstractAction {

     private final PovrayProject project;
     private final boolean isClose;

     OtherProjectAction(PovrayProject project, boolean isClose) {
 	putValue(NAME, isClose ? Bundle.LBL_CloseProject() : Bundle.LBL_SetMainProject());
 	this.project = project;
 	this.isClose = isClose;
     }

     @Override
     public void actionPerformed(ActionEvent actionEvent) {
 	if (isClose) {
 	    OpenProjects.getDefault().close(new Project[]{project});
 	} else {
 	    OpenProjects.getDefault().setMainProject(project);
 	}
     }

 }
 ----


 [start=5]
 1. Run the application and right-click on a POV-Ray project node. Notice that we now have a much improved popup menu:


 image::images/povray_71_ch9_pic4.png[]

 If "Render Project" is chosen while no main file has been set, you will see this dialog, where you can set a main file, which will immediately result in the file being rendered:


 image::images/povray_71_ch9_pic5.png[]


 == Next Steps

 Congratulations! You have completed the POV-Ray tutorial. The  link:nbm-povray-10.html[next step] is to review the concepts you've learned and then continue your journey on the NetBeans Platform.
	//
	// Licensed to the Apache Software Foundation (ASF) under one
	// or more contributor license agreements. See the NOTICE file
	// distributed with this work for additional information
	// regarding copyright ownership. The ASF licenses this file
	// to you under the Apache License, Version 2.0 (the
	// "License"); you may not use this file except in compliance
	// with the License. You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing,
	// software distributed under the License is distributed on an
	// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	// KIND, either express or implied. See the License for the
	// specific language governing permissions and limitations
	// under the License.
	//

	= Writing POV-Ray Support for NetBeans IX—Build Support
	:jbake-type: platform_tutorial
	:jbake-tags: tutorials
	:jbake-status: published
	:syntax: true
	:source-highlighter: pygments
	:toc: left
	:toc-title:
	:icons: font
	:experimental:
	:description: Writing POV-Ray Support for NetBeans IX—Build Support - Apache NetBeans
	:keywords: Apache NetBeans Platform, Platform Tutorials, Writing POV-Ray Support for NetBeans IX—Build Support

	This is a continuation of the tutorial for building a POV-Ray rendering application on the NetBeans Platform. If you have not read the link:nbm-povray-1.html[first], link:nbm-povray-2.html[second], link:nbm-povray-3.html[third], link:nbm-povray-4.html[fourth], link:nbm-povray-5.html[fifth] link:nbm-povray-6.html[sixth], link:nbm-povray-7.html[seventh], and link:nbm-povray-8.html[eighth] parts of this tutorial, you may want to start there.


	== Project Action Support

	You may recall that early on, when we were writing `PovrayProject`, we stubbed out the implementation of `PovrayProject.ActionsProviderImpl`—so in fact the build, clean and run actions are all disabled when a POV-Ray project is active. We should quickly implement them.

	Open `PovrayProject` in the code editor, and implement the methods of `ActionProviderImpl` as follows:


	[source,java]
	----

	private final class ActionProviderImpl implements ActionProvider {

	@Override
	public String[] getSupportedActions() {
	return new String[]{
	ActionProvider.COMMAND_BUILD,
	ActionProvider.COMMAND_CLEAN,
	ActionProvider.COMMAND_COMPILE_SINGLE
	};
	}

	@Override
	public void invokeAction(String string, Lookup lookup) throws IllegalArgumentException {
	int idx = Arrays.asList(getSupportedActions()).indexOf(string);
	switch (idx) {
	case 0: //build
	final RendererService ren = (RendererService) getLookup().lookup(RendererService.class);
	RequestProcessor.getDefault().post(new Runnable() {
	@Override
	public void run() {
	FileObject image = ren.render();
	//If we succeeded, try to open the image
	if (image != null) {
	DataObject dob;
	try {
	dob = DataObject.find(image);
	OpenCookie open = (OpenCookie) dob.getNodeDelegate().getLookup().lookup(OpenCookie.class);
	if (open != null) {
	open.open();
	}
	} catch (DataObjectNotFoundException ex) {
	Exceptions.printStackTrace(ex);
	}
	}
	}
	});
	break;
	case 1: //clean
	FileObject fob = getImagesFolder(false);
	if (fob != null) {
	DataFolder fld = DataFolder.findFolder(fob);
	for (Enumeration en = fld.children(); en.hasMoreElements();) {
	DataObject ob = (DataObject) en.nextElement();
	try {
	ob.delete();
	} catch (IOException ioe) {
	Exceptions.printStackTrace(ioe);
	}
	}
	}
	break;
	case 2: //compile-single
	final DataObject ob = (DataObject) lookup.lookup(DataObject.class);
	if (ob != null) {
	final RendererService ren1 = (RendererService) getLookup().lookup(RendererService.class);
	RequestProcessor.getDefault().post(new Runnable() {
	@Override
	public void run() {
	if (ob.isValid()) { //Could theoretically change before we run
	ren1.render(ob.getPrimaryFile());
	}
	}
	});
	}
	break;
	default:
	throw new IllegalArgumentException(string);
	}
	}

	@Override
	public boolean isActionEnabled(String string, Lookup lookup) throws IllegalArgumentException {
	int idx = Arrays.asList(getSupportedActions()).indexOf(string);
	boolean result;
	switch (idx) {
	case 0: //build
	result = true;
	break;
	case 1: //clean
	result = getImagesFolder(false) != null
	&& getImagesFolder(false).getChildren().length > 0;
	break;
	case 2: //compile-single
	DataObject ob = (DataObject) lookup.lookup(DataObject.class);
	if (ob != null) {
	FileObject file = ob.getPrimaryFile();
	result = "text/x-povray".equals(file.getMIMEType());
	} else {
	result = false;
	}
	break;
	default:
	result = false;
	}
	return result;
	}

	}
	----


	== Ensuring There Is A Main File

	We now have handling implemented for all of the standard project actions that make sense for a POV-Ray project. Now, if you've been following very carefully, you may have noticed that there is one bug we need to fix: `isActionEnabled()` will always return true for build. But we implemented the following code in `Povray.getFileToRender()`:


	[source,java]
	----

	render = provider.getMainFile();
	if (render == null) {
	ProjectInformation info = (ProjectInformation) proj.getLookup().lookup(ProjectInformation.class);
	//XXX let the user choose
	throw new IOException(NbBundle.getMessage(Povray.class, "MSG_NoMainFile", info.getDisplayName()));
	}
	----

	So if there is no main file set for a project, the build action will be enabled, but if it is invoked, it will throw an exception! The simple choice would be to test if there is a main file, and if not, disable the build action—but this would be rather non-intuitive to the user who might not be able to figure out what is wrong with the project. And we would miss an opportunity to explore the Explorer & Property Sheet API, together with the Dialogs APIs!

	So instead, we will post a dialog which will allow the user to choose which file should be the main file, if none is set when build is called:


	[start=1]
	1. On the Povray Project module, following the procedure outlined in previous sections of this tutorial, add a module dependency on the Explorer & Property Sheet API.

	[start=2]
	1. Right-click the `org.netbeans.examples.modules.povproject` package and chose New > Other > Swing GUI Forms > JPanel Form. Click Next. Name The JPanel "MainFileChooser" and click Finish. The GUI Designer (Matisse) will open.

	[start=3]
	1. In the Palette (Ctrl-Shift-8), click the item for `JLabel` and drag it to the top of the `JPanel`. Drag the right-hand edge of the `JLabel` to the right edge of the `JPanel` so that the `JLabel` will resize automatically at runtime.

	[start=4]
	1.
	In the Palette, click the item for `JScrollPane` and drag it to the `JPanel` below the `JLabel`. Drag the bottom right corner of the `JScrollPane` down and to the right until the bottom and right edge alignment guidelines appear. The result should look like this:


	image::images/povray_71_ch9_pic1.png[]


	[start=5]
	1. Make sure the Properties window (Ctrl-Shift-7) is open. Select the `JLabel` and and then click the [...] button for its `text` property in the Properties window. A custom editor will open:


	image::images/povray_71_ch9_pic2.png[]


	[start=6]
	1. Change the drop-down at the top of the dialog to "Custom code", as shown below, and then type ``Bundle.LBL_ChooseMainFile()`` :


	image::images/povray_71_ch9_pic3.png[]

	Click OK. Now add this annotation above the class signature:

	@NbBundle.Messages("LBL_ChooseMainFile=Select Main File")

	[source,java]
	----

	public class MainFileChooser extends javax.swing.JPanel {
	----

	Save the file. Now the annotation is converted to a String constant in a ``Bundle`` class and the reference to this class in the ``initComponents`` block should not show an error anymore.


	[start=7]
	1. Edit the signature of the class so that it implements the interface `ExplorerManager.Provider`:

	[source,java]
	----

	public class MainFileChooser extends javax.swing.JPanel implements ExplorerManager.Provider {
	----


	[start=8]
	1. Add the following code to implement `ExplorerManager.Provider`:

	[source,java]
	----

	private final ExplorerManager mgr = new ExplorerManager();

	public ExplorerManager getExplorerManager() {
	return mgr;
	}
	----


	[start=9]
	1. Modify the constructor so it reads as follows:


	[source,java]
	----

	public MainFileChooser(PovrayProject proj) {

	initComponents();

	setLayout(new BorderLayout());

	LogicalViewProvider logicalView = (LogicalViewProvider) proj.getLookup().lookup(LogicalViewProvider.class);

	Node projectNode = logicalView.createLogicalView();

	mgr.setRootContext(new FilterNode(projectNode, new ProjectFilterChildren(projectNode)));

	BeanTreeView btv = new BeanTreeView();

	jScrollPane1.setViewportView(btv);

	btv.setPopupAllowed(false);

	btv.setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);

	add(btv, BorderLayout.CENTER);

	}
	----

	The `BeanTreeView` we are showing is a UI class from the Explorer API—in fact, it is the very same component that you see in the Projects, Files, Runtime and Favorites tabs in the NetBeans IDE.

	What it will do is, when it is added to a component, search through the hierarchy of parent components until it finds one that implements `ExplorerManager.Provider`. That component's `ExplorerManager` will then become the place where the tree view gets its root node to display, and will be what it notifies when the selection changes.

	NOTE: An error mark will remain for `ProjectFilterNode` because we have not yet written it.


	[start=10]
	1. Now we need to implement `ProjectFilterNode`. The Nodes API contains a class, `FilterNode`, which makes it possible to take one `Node`, and create another `Node` which "filters" the original `Node`—providing different children, actions, properties or whatever it chooses to.

	In our case, we want a `FilterNode` that will filter out any files that do not have the MIME type `text/x-povray`—so that, if the user has a text file or an image file or such in their project, they cannot set that to be the main file and try to pass it to POV-Ray.

	We don't actually need to implement `FilterNode`, we simply need to provide an alternate `Children` object which filters out files we don't want. Implement this as a nested class inside `MainFileChooser`:


	[source,java]
	----

	private static final class ProjectFilterChildren extends FilterNode.Children {

	ProjectFilterChildren(Node projectNode) {
	super(projectNode);
	}

	@Override
	protected Node[] createNodes(Node object) {
	Node origChild = (Node) object;
	DataObject dob = (DataObject) origChild.getLookup().lookup(DataObject.class);
	if (dob != null) {
	FileObject fob = dob.getPrimaryFile();
	if ("text/x-povray".equals(fob.getMIMEType())) {
	return super.createNodes(object);
	} else if (dob instanceof DataFolder) {
	//Allow child folders of the scenes/ dir
	return new Node[]{
	new FilterNode(origChild,
	new ProjectFilterChildren(origChild))
	};
	}
	}
	//Don't create any nodes for non-povray files
	return new Node[0];
	}

	}
	----


	[start=11]
	1. Now we just need some code to use this panel. That code will go in `RenderServiceImpl`, before we call `Povray.render()`. Reimplement the no-argument version of the `render()` method as follows:


	[source,java]
	----

	@Override
	public FileObject render() {
	MainFileProvider mfp = (MainFileProvider) proj.getLookup().lookup(MainFileProvider.class);
	assert mfp != null;
	if (mfp.getMainFile() == null) {
	showChooseMainFileDlg(mfp);
	}
	if (mfp.getMainFile() != null) {
	return render(null);
	} else {
	return null;
	}
	}
	----


	[start=12]
	1. Now we need to implement the method we are calling above, `showChooseMainFileDlg()`. This is the method which will ask the user to pick a main file. It will use the Dialogs API to show a dialog containing an instance of `MainFileChooser`, and enable the OK button once a file is selected. If the user selects a POV-Ray file, it will be stored in `MainFileProvider`, and so it will be non-null when we return to the `render()` method, and so `render()` will proceed:


	[source,java]
	----

	@NbBundle.Messages("TTL_ChooseMainFile=Choose Main File")
	private void showChooseMainFileDlg(final MainFileProvider mfp) {

	final MainFileChooser chooser = new MainFileChooser(proj);

	String title = Bundle.TTL_ChooseMainFile();

	//Create a simple dialog descriptor describing what kind of dialog
	//we want and its title and contents
	final DialogDescriptor desc = new DialogDescriptor(chooser, title);

	//The OK button should be disabled initially
	desc.setValid(false);

	//Create a property change listener. It will listen on the selection
	//in our MainFileChooser, and enable the OK button if an appropriate
	//node is selected:
	PropertyChangeListener pcl = new PropertyChangeListener() {
	@Override
	public void propertyChange(PropertyChangeEvent pce) {
	String propName = pce.getPropertyName();
	if (ExplorerManager.PROP_SELECTED_NODES.equals(propName)) {
	Node[] n = (Node[]) pce.getNewValue();
	boolean valid = n.length == 1;
	if (valid) {
	DataObject ob = (DataObject) n[0].getLookup().lookup(DataObject.class);
	valid = ob != null;
	if (valid) {
	FileObject selectedFile = ob.getPrimaryFile();
	String mimeType = selectedFile.getMIMEType();
	valid = "text/x-povray".equals(mimeType);
	}
	}
	desc.setValid(valid);
	}
	}
	};
	chooser.getExplorerManager().addPropertyChangeListener(pcl);

	//Show the dialog—dialogResult will be OK or Cancel
	Object dialogResult = DialogDisplayer.getDefault().notify(desc);

	//If the user clicked OK, try to set the main file
	//from the selection
	if (DialogDescriptor.OK_OPTION.equals(dialogResult)) {

	//Get the selected Node
	Node[] n = chooser.getExplorerManager().getSelectedNodes();

	//If it's > 1, explorer is broken—we set
	//single selection mode
	assert n.length <= 1;
	DataObject ob = (DataObject) n[0].getLookup().lookup(
	DataObject.class);

	//Get the file from the data object
	FileObject selectedFile = ob.getPrimaryFile();

	//And save it as the main file
	mfp.setMainFile(selectedFile);

	}

	}
	----


	== Extending the Project Popup Menu

	Right now, if you run the application and open a new POV-Ray project and right-click on it, there are no render or clean actions. The first thing we can do is improve the popup menu for POV-Ray projects—we need to add a couple of menu items to those already returned.


	[start=1]
	1. Open `PovrayLogicalView` in the editor, and find the inner `ScenesNode` class.

	[start=2]
	1.
	Override `getActions()` as follows:


	[source,java]
	----

	@NbBundle.Messages({
	"LBL_Build=Render Project",
	"LBL_Clean=Clean Project"
	})
	@Override
	public Action[] getActions(boolean popup) {
	Action[] result = new Action[]{
	new ProjectAction(ActionProvider.COMMAND_BUILD, Bundle.LBL_Build(), project),
	new ProjectAction(ActionProvider.COMMAND_CLEAN, Bundle.LBL_Clean(), project),
	new OtherProjectAction(project, false),
	SystemAction.get(NewTemplateAction.class),
	SystemAction.get(FileSystemAction.class),
	new OtherProjectAction(project, true),
	};
	return result;
	}
	----

	This gives us two classes to implement—`ProjectAction` and `OtherProjectAction`. The former will simply be an action class which delegates to the action provider of the project, and the other will use the `OpenProjects` class from the Project UI API to close the project.


	[start=3]
	1. Implement `ProjectAction` as follows:


	[source,java]
	----

	private static class ProjectAction extends AbstractAction {

	private final PovrayProject project;
	private final String command;

	public ProjectAction(String cmd, String displayName, PovrayProject prj) {
	this.project = prj;
	putValue(NAME, displayName);
	this.command = cmd;
	}

	@Override
	public void actionPerformed(ActionEvent actionEvent) {
	ActionProvider prov = (ActionProvider) project.getLookup().lookup(ActionProvider.class);
	prov.invokeAction(command, null);
	}

	@Override
	public boolean isEnabled() {
	ActionProvider prov = (ActionProvider) project.getLookup().lookup(ActionProvider.class);
	return prov.isActionEnabled(command, null);
	}

	}
	----


	[start=4]
	1. Then implement the brilliantly named `OtherProjectAction` this way, also as a nested class inside PovrayLogicalView. What we're doing here is saving the overhead of one more class to do something simple, and writing one action that either closes the project or makes it the main project, depending on a flag. While not beautiful, it is short enough to be readable—and additional classes do come with a memory penalty, so for trivial things, this approach is not necessarily a bad idea—as long as the result is readable:


	[source,java]
	----

	@NbBundle.Messages({
	"LBL_CloseProject=Close Project",
	"LBL_SetMainProject=Set Main Project"
	})
	private static class OtherProjectAction extends AbstractAction {

	private final PovrayProject project;
	private final boolean isClose;

	OtherProjectAction(PovrayProject project, boolean isClose) {
	putValue(NAME, isClose ? Bundle.LBL_CloseProject() : Bundle.LBL_SetMainProject());
	this.project = project;
	this.isClose = isClose;
	}

	@Override
	public void actionPerformed(ActionEvent actionEvent) {
	if (isClose) {
	OpenProjects.getDefault().close(new Project[]{project});
	} else {
	OpenProjects.getDefault().setMainProject(project);
	}
	}

	}
	----


	[start=5]
	1. Run the application and right-click on a POV-Ray project node. Notice that we now have a much improved popup menu:


	image::images/povray_71_ch9_pic4.png[]

	If "Render Project" is chosen while no main file has been set, you will see this dialog, where you can set a main file, which will immediately result in the file being rendered:


	image::images/povray_71_ch9_pic5.png[]


	== Next Steps

	Congratulations! You have completed the POV-Ray tutorial. The link:nbm-povray-10.html[next step] is to review the concepts you've learned and then continue your journey on the NetBeans Platform.