Description of Layer Registrations in NetBeans APIs

Registration of various objects, files and hints into layer is pretty central to the way NetBeans based applications handle communication between modules. This page summarizes the list of such extension points defined by modules with API.

OptionsDialogSPILayers in Options Dialog and SPI
Use OptionsDialog folder for registration of custom top level options panels. Register your implementation of OptionsCategory there (*.instance file). Standard file systems sorting mechanism is used.
AdvancedPanelSPILayers in Options Dialog and SPI
Use OptionsDialog/Advanced folder for registration of custom panels to Miscellaneous Panel. Register your implementation of AdvancedCategory there (*.instance file). Standard file systems sorting mechanism is used.

OptionsExportLayers in Options Dialog and SPI

Use OptionsExport/<MyCategory> folder for registration of items for export/import of options. Registration in layers looks as follows

 <folder name="OptionsExport">
     <!-- category -->
     <folder name="MyCategory">
         <!-- category display name -->
         <attr name="displayName"
          bundlevalue="org.netbeans.modules.mymodule.options.Bundle#Category_Display_Name"/>
         <!-- item -->
         <file name="MyItem1">
             <attr name="displayName" bundlevalue="org.netbeans.modules.mymodule.options.Bundle#Item1_Display_Name"/>
             <!-- include regex pattern rooted to userdir -->
             <attr name="include" stringvalue="config/Preferences/org/netbeans/modules/mymodule/.*|config/mymodule/.*"/>
             <!-- exclude regex pattern rooted to userdir -->
             <attr name="exclude" stringvalue="config/mymodule/obsolete/.*"/>
         </file>
         <!-- item -->
         <file name="MyItem2">
             <attr name="displayName" bundlevalue="org.netbeans.modules.mymodule.options.Bundle#Item2_Display_Name"/>
             <!-- include pattern with properties constrain -->
             <attr name="include" stringvalue="config/mymodule[.]properties#key[1-9].*|keyA.*#|config/mymodule[.]xml"/>
             <!-- exclude pattern with properties constrain  -->
             <attr name="exclude" stringvalue="config/obsolete[.]properties#key5"/>
         </file>
     </folder>
 </folder>

Include/exclude patterns may contain either a regular expression defining files relatively to userdir (see MyItem1) or a compound pattern defining files and property keys (see MyItem2). A compound pattern consists of file regex pattern followed by hash delimiter (#) then property key regex pattern followed by another hash delimiter. Hash delimiter can be ommited at the end of compound pattern. For example, a compound pattern can have the following structure filePattern1#keyPattern1#|filePattern2|filePattern3#keyPattern3.

RuntimeInstancesRegistry in Settings API
xml/memory: Associates runtime instance with environment provider.
ServicesDisplayRegistry in Settings API
UI/Services: The root folder for displaying options in the deprecated Advanced dialog.
UI-ToolActions in Actions APIs
Register your javax.swing.Action instances in UI/ToolActions folder to make them known to ToolsAction.
Actions.factories in UI Utilities API
Many action factories (alwaysEnabled, context and callback, etc.) are ready to be called directly from layer XML file.
methodvalue-newvalue in File System API
When special form of setAttribute is supported by the filesystem, the getAttribute can behave like XMLFileSystem's methodvalue and newvalue attributes:
- "-//NetBeans//DTD DefaultAttributes 1.0//EN"
- "-//NetBeans//DTD Filesystem 1.0//EN"
raw-value in File System API
It is possible to prefix call to FileObject.getAttribute with raw: prefix to evaluate the attribute without instantiating it (e.g. get Method or Class values from methodvalue and newvalue attributes. This API is not intended for public use at present and can change in future.
Loaders-folder-any-Actions in Datasystems API
The actions that the default folder loader shows in its popup menu are read from a layer folder Loaders/folder/any/Actions so if any module wishes to extend, hide or reorder some of them it can just register its actions there.
Loaders-text-xml-Actions in Datasystems API
The actions that the standard XML loader shows in its popup menu are read from a layer folder Loaders/text/xml/Actions
Loaders-content-unknown-Actions in Datasystems API
The actions that the loader for unrecognized files shows in its popup menu are read from a layer folder Loaders/content/unknown/Actions
Loaders-application-x-nbsettings-Actions in Datasystems API
The actions that the loader for instance and settings files shows in its popup menu are read from a layer folder Loaders/application/x-nbsettings/Actions
Loaders-folder-any-Actions in Datasystems API
The actions that the default folder loader shows in its popup menu are read from a layer folder Loaders/folder/any/Actions so if any module wishes to extend, hide or reorder some of them it can just register its actions there.
Loaders-text-xml-Actions in Datasystems API
The actions that the standard XML loader shows in its popup menu are read from a layer folder Loaders/text/xml/Actions
Loaders-content-unknown-Actions in Datasystems API
The actions that the loader for unrecognized files shows in its popup menu are read from a layer folder Loaders/content/unknown/Actions
Loaders-application-x-nbsettings-Actions in Datasystems API
The actions that the loader for instance and settings files shows in its popup menu are read from a layer folder Loaders/application/x-nbsettings/Actions
Loaders-mime-type-Factories in Datasystems API
Loaders are registered in the layer in folder Loaders/mime/type/Factories.
PrivilegedTemplates in Datasystems API
A folder Privileged offers to other module possibility add own templates.
RecentTemplates in Datasystems API
A folder Recent stores a set of recently used templates, it's not open to other module.
Menu in Datasystems API

The main menu of the application is composed by reading Menu/ folder in the layer. A sub folder is treated as a sub menu. Instances of individual files (usually .instance or .shadow) may then represent Action or JMenuItem or JSeparator.

Since version 7.44 one can attach property-prefix attribute to every folder. Then all the file attributes are scanned and if some of them start with the specified prefix they are placed a client properties on the JMenu instance (after stripping the prefix off).
Editors-TabActions in Text API
Actions for the editor tab (window) context menu can be injected into Editors/TabActions.
NewConfigurationData in Window System API
new configuration data
OldConfigurationData in Window System API
old configuration data
ModuleDataStructure in Window System API
Module folder structure under Windows2 directory
LocalDataStructure in Window System API
Local folder structure under Windows2Local directory

To get your API listed here, use <api type='export' group='layer' ... /> in your module arch.xml document.