How do I add support for an XML type with a different extension?

I want to add some special

functionality to the initial handling of xml files with a xul extension, but

then allow users to use the existing NB functionality for editing,

validation etc.

Did you solve this without patching?

In 5.0, it can be done without a patch. It does, however, require an impl dependency on xml-core. I’d really like this to be simpler, and a supported API.

See below for issues with pre-release 6.0

Anyway, here’s how I do it for an xml flavor called SCXML:

The loader:

import java.io.IOException;
import org.netbeans.modules.xml.core.XMLDataLoader;
import org.openide.filesystems.FileObject;
import org.openide.loaders.DataObjectExistsException;
import org.openide.loaders.MultiDataObject;
import org.openide.loaders.UniFileLoader;
import org.openide.util.NbBundle;

public class ScxmlDataLoader extends UniFileLoader
{

    public static final String REQUIRED_MIME = "application/scxml+xml";

    private static final long serialVersionUID = 1L;

    public ScxmlDataLoader()
    {
        super("com.nuance.tools.xhmi.ScxmlDataObject");
    }

    protected String defaultDisplayName()
    {
        return NbBundle.getMessage(ScxmlDataLoader.class, "LBL_Scxml_loader_name");
    }

    protected void initialize()
    {
        super.initialize();
        getExtensions().addMimeType(REQUIRED_MIME);
    }

    protected MultiDataObject createMultiObject(FileObject primaryFile) throws DataObjectExistsException, IOException
    {
        return new ScxmlDataObject(primaryFile, this);
    }

    protected MultiDataObject.Entry createPrimaryEntry (MultiDataObject obj, FileObject primaryFile) {
        return new XMLDataLoader.XMLFileEntry (obj, primaryFile); //adds smart templating
    }

    protected String actionsContext()
    {
        return "Loaders/" + REQUIRED_MIME + "/Actions";
    }
}

The data object:

import java.io.IOException;
import org.netbeans.modules.xml.core.XMLDataObjectLook;
import org.netbeans.modules.xml.core.cookies.DataObjectCookieManager;
import org.netbeans.modules.xml.core.sync.DataObjectSyncSupport;
import org.netbeans.modules.xml.core.sync.Synchronizator;
import org.netbeans.modules.xml.core.text.TextEditorSupport;
import org.netbeans.spi.xml.cookies.CheckXMLSupport;
import org.netbeans.spi.xml.cookies.DataObjectAdapters;
import org.netbeans.spi.xml.cookies.ValidateXMLSupport;
import org.openide.filesystems.FileObject;
import org.openide.loaders.DataObjectExistsException;
import org.openide.loaders.MultiDataObject;
import org.openide.nodes.CookieSet;
import org.openide.nodes.Node;
import org.openide.text.DataEditorSupport;
import org.xml.sax.InputSource;

public class ScxmlDataObject extends MultiDataObject implements
XMLDataObjectLook
{
    private transient final DataObjectCookieManager cookieManager;
    private transient Synchronizator synchronizator;

    public ScxmlDataObject(FileObject pf, ScxmlDataLoader loader) throws DataObjectExistsException, IOException {
        super(pf, loader);
        CookieSet cookies = getCookieSet();
        cookieManager = new DataObjectCookieManager (this, cookies);

        cookies.add((Node.Cookie) DataEditorSupport.create(this, getPrimaryEntry(), cookies));

        InputSource is = DataObjectAdapters.inputSource(this);
        cookies.add(new CheckXMLSupport(is));
        cookies.add(new ValidateXMLSupport(is));

        // editor support defines MIME type understood by EditorKits registry
        TextEditorSupport.TextEditorSupportFactory editorFactory =
            new TextEditorSupport.TextEditorSupportFactory (this, org.netbeans.modules.xml.core.XMLDataObject.MIME_TYPE);
        editorFactory.registerCookies (cookies);

    }

    protected Node createNodeDelegate() {
        return new ScxmlDataNode(this);
    }

    ////////// XMLDataObjectLook interface /////////////////
    public DataObjectCookieManager getCookieManager() {
        return cookieManager;
    }

    public synchronized Synchronizator getSyncInterface() {
        if (synchronizator == null) {
            synchronizator = new DataObjectSyncSupport (ScxmlDataObject.this);
        }
        return synchronizator;
    }
}

The layer file:

<filesystem>
    <folder name="Loaders">
        <folder name="application">
            <folder name="scxml+xml">
                <folder name="Actions">
                    <file name="org-openide-actions-OpenAction.instance"/>
                    <attr name="org-openide-actions-OpenAction.instance/org-openide-actions-FileSystemAction.instance" boolvalue="true"/>
                    <file name="org-openide-actions-FileSystemAction.instance"/>
                    <attr name="org-openide-actions-FileSystemAction.instance/sep-1.instance" boolvalue="true"/>
                    <file name="sep-1.instance">
                        <attr name="instanceClass" stringvalue="javax.swing.JSeparator"/>
                    </file>
                    <attr name="sep-1.instance/org-openide-actions-CutAction.instance" boolvalue="true"/>
                    <file name="org-openide-actions-CutAction.instance"/>
                    <attr name="org-openide-actions-CutAction.instance/org-openide-actions-CopyAction.instance" boolvalue="true"/>
                    <file name="org-openide-actions-CopyAction.instance"/>
                    <attr name="org-openide-actions-CopyAction.instance/sep-2.instance" boolvalue="true"/>
                    <file name="sep-2.instance">
                        <attr name="instanceClass" stringvalue="javax.swing.JSeparator"/>
                    </file>
                    <attr name="sep-2.instance/org-openide-actions-DeleteAction.instance" boolvalue="true"/>
                    <file name="org-openide-actions-DeleteAction.instance"/>
                    <attr name="org-openide-actions-DeleteAction.instance/org-openide-actions-RenameAction.instance" boolvalue="true"/>
                    <file name="org-openide-actions-RenameAction.instance"/>
                    <attr name="org-openide-actions-RenameAction.instance/sep-3.instance" boolvalue="true"/>
                    <file name="sep-3.instance">
                        <attr name="instanceClass" stringvalue="javax.swing.JSeparator"/>
                    </file>
                    <attr name="sep-3.instance/org-openide-actions-SaveAsTemplateAction.instance" boolvalue="true"/>
                    <file name="org-openide-actions-SaveAsTemplateAction.instance"/>
                    <attr name="org-openide-actions-SaveAsTemplateAction.instance/sep-4.instance" boolvalue="true"/>
                    <file name="sep-4.instance">
                        <attr name="instanceClass" stringvalue="javax.swing.JSeparator"/>
                    </file>
                    <attr name="sep-4.instance/org-openide-actions-ToolsAction.instance" boolvalue="true"/>
                    <file name="org-openide-actions-ToolsAction.instance"/>
                    <attr name="org-openide-actions-ToolsAction.instance/org-openide-actions-PropertiesAction.instance" boolvalue="true"/>
                    <file name="org-openide-actions-PropertiesAction.instance"/>
                </folder>
            </folder>
        </folder>
    </folder>
    <folder name="Services">
        <folder name="MIMEResolver">
            <file name="ScxmlResolver.xml" url="resources/ScxmlResolver.xml">
                <attr name="SystemFileSystem.localizingBundle" stringvalue="com.nuance.tools.xhmi.Bundle"/>
            </file>
        </folder>
    </folder>
    <folder name="Templates">
        <folder name="Other">
            <file name="ScxmlTemplate.scxml" url="resources/ScxmlTemplate.scxml">
                <attr name="SystemFileSystem.localizingBundle" stringvalue="com.nuance.tools.xhmi.Bundle"/>
                <attr name="template" boolvalue="true"/>
            </file>
        </folder>
    </folder>

the MIME resolver:

<MIME-resolver>
    <file>
        <ext name="scxml"/>
        <resolver mime="application/scxml+xml"/>
    </file>
</MIME-resolver>

Apache NetBeans 23

How do I add support for an XML type with a different extension?