NetBeans Project Type Extension Module Tutorial

This tutorial demonstrates how to extend an existing project type. New APIs in NetBeans IDE 6.0 enable you to add new nodes to an existing project type's logical view, additions to an existing project type's lookup, and new panels to an existing project type's Project Properties dialog box. To illustrate these extensions, we extend the web application project type, by adding a new 'Important Files' node, exposing the content of the project's 'nbproject' folder, as shown here:

New node

Prior to NetBeans IDE 6.0, no APIs existed for extending existing project types. Instead, you would need to create new ones from scratch. From 6.0 onwards, you are recommended to extend existing project types rather than create new ones. This will keep the number of project types to a minimum and avoid a large number of project types with very small differences.

Contents

Content on this page applies to NetBeans IDE 6.0

For more information on working with NetBeans modules, see the NetBeans Development Project home on the NetBeans website. If you have questions, visit the NetBeans Developer FAQ or use the feedback link at the end of this page.


Installing the Software

Before you begin, you need to install the following software on your computer:

You will also make use of this icon, which you can right-click here and download:

Creating the Module Project

We begin by working through the New Module Project wizard. At the end of it, we will have a basic source structure, with some default files, that every NetBeans module requires.

  1. Choose File > New Project (Ctrl-Shift-N). Under Categories, select NetBeans Plug-in Modules. Under projects, select Module Project.

    Click Next.

  2. In the Name and Location panel, type ImportantWebFiles in Project Name. Change the Project Location to any directory on your computer. Leave the Standalone Module radiobutton and the Set as Main Project checkbox selected.

    Click Next.

  3. In the Basic Module Configuration panel, replace yourorghere in Code Name Base with modules.netbeans, so that the whole code name base is org.modules.netbeans.importantwebfiles. Add a space to the default Module Display Name, so that it is changed to Important Web Files. Leave the location of the localizing bundle and XML layer, so that they will be stored in a package with the name org/modules.netbeans/importantwebfiles. The panel should now look as follows:

    Click Finish.

The IDE creates the Important Web Files project. The project contains all of your sources and project metadata, such as the project's Ant build script. The project opens in the IDE. You can view its logical structure in the Projects window (Ctrl-1) and its file structure in the Files window (Ctrl-2).

For basic information on each of the files above, see the Introduction to NetBeans Module Development.


Setting Dependencies

We will need to make use of several NetBeans APIs. In this step, we select the modules that provide the NetBeans APIs that we will need.

  1. Right-click the project node and choose Properties.

    The Project Properties dialog box opens.

  2. In the Libraries panel, add dependencies on the following modules:

    The Libraries panel should now look as follows:

    Select Project panel.

  3. Click OK.

Registering the New Extensions

Before we create the classes that implement the APIs that we registered above, we will add entries to the layer file.

  1. Expand the Important Files node and double-click the XML Layer node to open the file in the editor.

  2. Add the following entries to the layer file:

    <folder name="Projects">
        
        <folder name="org-netbeans-modules-web-project">
            
            <folder name="Lookup">
                <file name="org.netbeans.modules.importantwebfiles.LookupProviderImpl.instance"/>
            </folder>
            
            <folder name="Nodes">
                <file name="org.netbeans.modules.importantwebfiles.ImportantFilesNodeFactoryImpl.instance">
                    <attr name="position" intvalue="1200"/>
                </file>
            </folder>
            
        </folder>
        
    </folder>
  3. In the Important Files node, expand the XML Layer node, then expand the 'this layer in context' node. Scroll to the Projects node and notice that the changes you made above are highlighted, to visually distinguish your extensions from those that were there already:

    Select Project panel.

    Note: The visual view above is very useful in showing you the names of the project types, so that you can correctly register extensions to them in the layer file.


Extending the Lookup

We start by implementing the LookupProviderImpl class, which we registered in the layer file in the previous section.

  1. Create a Java class called LookupProviderImpl.
  2. Change the default code to the following:

    public class LookupProviderImpl implements LookupProvider {
    
        public Lookup createAdditionalLookup(Lookup lookup) {
            
            Project prj = lookup.lookup(Project.class);
            
            //If there is a web module provider in the
            //project's lookup, add a new lookup item to
            //the lookup, which we will look for to determine
            /whether a node should be created:
            WebModuleProvider wmp = lookup.lookup(WebModuleProvider.class);
            if (wmp != null) {
                return Lookups.fixed(new MyCoolLookupItem(prj));
            }
            
            //If there is no web module in the lookup,
            //we do not add a new item to our lookup,
            //so that later a node will not be created:
            return Lookups.fixed();
            
        }
    
    }
  3. Create a new Java class called MyCoolLookupItem.
  4. Change the default code to the following:

    public class MyCoolLookupItem {
    
        public MyCoolLookupItem(Project prj) {
        }
    
    }

Extending the Logical View

We start by implementing the LookupProviderImpl class, which we registered in the layer file in the previous section.

  1. Create a Java class called ImportantFilesNodeFactoryImpl.
  2. Change the default code to the following:

    public class ImportantFilesNodeFactoryImpl implements NodeFactory {
    
        Project proj;
    
        public NodeList createNodes(Project project) {
          
            this.proj = project;
            
            //If there is no 'nbproject' folder,
            //return an empty list of nodes:
            if (proj.getProjectDirectory().getFileObject("nbproject") == null) {
                return NodeFactorySupport.fixedNodeList();
            }
            
            //If our item is in the project's lookup,
            //return a new node in the node list:
            MyCoolLookupItem item = project.getLookup().lookup(MyCoolLookupItem.class);
            if (item != null) {
                try {
                    ImportantFilesNode nd = new ImportantFilesNode(proj);
                    return NodeFactorySupport.fixedNodeList(nd);
                } catch (DataObjectNotFoundException ex) {
                    Exceptions.printStackTrace(ex);
                }
            }
            
            //If our item isn't in the lookup,
            //then return an empty list of nodes:
            return NodeFactorySupport.fixedNodeList();
            
        }
        
    }
  3. Create a new Java class called ImportantFilesNode.
  4. Change the default code to the following:

    public class ImportantFilesNode extends FilterNode {
    
        private static Image smallImage = 
              Utilities.loadImage("/org/netbeans/modules/importantwebfiles/webPagesBadge.gif"); // NOI18N
    
        public ImportantFilesNode(Project proj) throws DataObjectNotFoundException {
            super(DataObject.find(proj.getProjectDirectory().getFileObject("nbproject")).getNodeDelegate());
        }
    
        public String getDisplayName() {
            return "Important Files";
        }
         
        //Next, we add icons, for the default state, which is
        //closed, and the opened state; we will make them the same. 
        //Icons in project logical views are
        //based on combinations--you must combine the node's own icon
        //with a distinguishing badge that is merged with it. Here we
        //first obtain the icon from a data folder, then we add our
        //badge to it by merging it via a NetBeans API utility method:
        
        public Image getIcon(int type) {
            DataFolder root = DataFolder.findFolder(Repository.getDefault().getDefaultFileSystem().getRoot());
            Image original = root.getNodeDelegate().getIcon(type);
            return Utilities.mergeImages(original, smallImage, 7, 7);
        }
    
        public Image getOpenedIcon(int type) {
            DataFolder root = DataFolder.findFolder(Repository.getDefault().getDefaultFileSystem().getRoot());
            Image original = root.getNodeDelegate().getIcon(type);
            return Utilities.mergeImages(original, smallImage, 7, 7);
        }
        
    }

Installing the Module

Finally, we install the module and make use of the result.

  1. Check that the module looks as follows in the Projects window:

    finished project

  2. Right-click the module project and install it.
  3. Create a new web application, or open an existing one, and notice that it has an Important Files node, containing the files from the 'nbproject' folder:

    installed result


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Next Steps

For more information about creating and developing NetBeans modules, see the following resources:


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