Configuring an Extensions Bundle

All extensions that are provided by Oxygen XML Author Eclipse plugin are includes in a single bundle.

Note: The individual extensions can still be set (open the Preferences dialog box , go to Document Type Association, double-click a document type, and go to the extension tab), and if present, they take precedence over the single provider. However, this practice is discouraged and the single provider should be used instead.

The extensions bundle is represented by the ro.sync.ecss.extensions.api.ExtensionsBundle class. The provided implementation of the ExtensionsBundle is instantiated when the Document Type Association rules defined for the custom framework matches a document opened in the editor. Therefore, references to objects that need to be persistent throughout the application running session must not be kept in the bundle because the next detection event can result in creating another ExtensionsBundle instance.

To configure an extensions bundle, follow this procedure:

Create a new Java project in your IDE. Create a lib folder in the Java project folder and copy in it the oxygen.jar file from the [OXYGEN_INSTALL_DIR]/lib folder.
Create the class (for example, simple.documentation.framework.SDFExtensionsBundle) to extend the abstract class ro.sync.ecss.extensions.api.ExtensionsBundle.
For example:
```
public class SDFExtensionsBundle extends ExtensionsBundle {
```
A Document Type ID and a short description should be defined by implementing the getDocumentTypeID and getDescription methods. The Document Type ID is used to uniquely identify the current framework. Such an ID must be provided especially if options related to the framework need to be persistently stored and retrieved between sessions.
For example:
```
public String getDocumentTypeID() {
    return "Simple.Document.Framework.document.type";
}

public String getDescription() {
    return "A custom extensions bundle used for the Simple Document" + 
           "Framework document type";
}
```
[Optional] To be notified about the activation of the custom Author Extension in relation with an open document, ro.sync.ecss.extensions.api.AuthorExtensionStateListener should be implemented. The activation and deactivation events received by this listener should be used to perform custom initializations and to register or remove listeners such as ro.sync.ecss.extensions.api.AuthorListener, ro.sync.ecss.extensions.api.AuthorMouseListener, or ro.sync.ecss.extensions.api.AuthorCaretListener. The custom Author Extension state listener should be provided by implementing the createAuthorExtensionStateListener method.
For example:
```
public AuthorExtensionStateListener createAuthorExtensionStateListener() {
    return new SDFAuthorExtensionStateListener();
}
```
The AuthorExtensionStateListener is instantiated and notified about the activation of the framework when the rules of the Document Type Association match a document opened in the Author editing mode. The listener is notified about the deactivation when another framework is activated for the same document, the user switches to another mode or the editor is closed. A complete description and implementation of ro.sync.ecss.extensions.api.AuthorExtensionStateListener can be found in Implementing an Author Extension State Listener.

If Schema-Aware mode is active in Oxygen XML Author Eclipse plugin, all actions that can generate invalid content will be redirected toward the ro.sync.ecss.extensions.api.AuthorSchemaAwareEditingHandler. The handler can resolve a specific case, let the default implementation take place, or reject the edit entirely by throwing ro.sync.ecss.extensions.api.InvalidEditException. The actions that are forwarded to this handler include typing, delete, or paste.

For more details about this handler, see Handling Schema-Aware Editing Events.
[Optional] You can customize the content completion proposals by creating a schema manager filter extension. The interface that declares the methods used for content completion proposals filtering is ro.sync.contentcompletion.xml.SchemaManagerFilter. The filter can be applied on elements, attributes, or on their values. The createSchemaManagerFilter method is responsible for creating the content completion filter. A new SchemaManagerFilter will be created each time a document matches the rules defined by the Document Type Association that contains the filter declaration.
For example:
```
public SchemaManagerFilter createSchemaManagerFilter() {
    return new SDFSchemaManagerFilter();
}
```
A detailed presentation of the schema manager filter can be found in the Configuring a Content Completion Handler section.
[Optional] The Author mode supports link-based navigation between documents and document sections. Therefore, if the document contains elements defined as links to other elements (for example, links based on the @id attributes), the extension should provide the means to find the referenced content. To do this, an implementation of the ro.sync.ecss.extensions.api.link.ElementLocatorProvider interface should be returned by the createElementLocatorProvider method. Each time an element pointed by a link needs to be located, the method is invoked.
For example:
```
public ElementLocatorProvider createElementLocatorProvider() {
    return new DefaultElementLocatorProvider();
}
```
For more information on how to implement an element locator provider, see the Configuring a Link Target Element Finder section.
[Optional] The drag and drop functionality can be extended by implementing the ro.sync.exml.editor.xmleditor.pageauthor.AuthorDnDListener interface. Relevant methods from the listener are invoked when the mouse is dragged, moved over, or exits the Author editing mode, when the drop action changes, and when the drop occurs. Each method receives the DropTargetEvent containing information about the drag and drop operation. The drag and drop extensions are available in Author mode for both Oxygen XML Author Eclipse plugin Eclipse plugin and standalone application. The Text mode corresponding listener is available only for Oxygen XML Author Eclipse plugin Eclipse plugin. The methods corresponding to each implementation are: createAuthorAWTDndListener, createTextSWTDndListener, and createAuthorSWTDndListener.
```
public AuthorDnDListener createAuthorAWTDndListener() {
    return new SDFAuthorDndListener();
}
```
For more details about the Author mode drag and drop listeners, see the Configuring a custom Drag and Drop Listener section.
[Optional] Another extension that can be included in the bundle is the reference resolver. For example, the references represented by the ref element and the attribute indicating the referenced resource is location. To be able to obtain the content of the referenced resources you will have to implement a Java extension class that implements ro.sync.ecss.extensions.api.AuthorReferenceResolver. The method responsible for creating the custom references resolver is createAuthorReferenceResolver. The method is called each time a document opened in an Author editing mode matches the Document Type Association where the extensions bundle is defined. The instantiated references resolver object is kept and used until another extensions bundle corresponding to another document type is activated as result of the detection process.
For example:
```
public AuthorReferenceResolver createAuthorReferenceResolver() {
    return new ReferencesResolver();
}
```
A more detailed description of the references resolver can be found in the Configuring a References Resolver section.
[Optional] To be able to dynamically customize the default CSS styles for a certain ro.sync.ecss.extensions.api.node.AuthorNode, an implementation of ro.sync.ecss.extensions.api.StylesFilter can be provided. The extensions bundle method responsible for creating the StylesFilter is createAuthorStylesFilter. The method is called each time a document opened in an Author editing mode matches the Document Type Association where the extensions bundle is defined. The instantiated filter object is kept and used until another extensions bundle corresponding to another document type is activated as a result of the detection process.
For example:
```
public StylesFilter createAuthorStylesFilter() {
    return new SDFStylesFilter();
}
```
See the Configuring CSS Styles Filter section for more details about the styles filter extension.
[Optional] To edit data in custom tabular format, implementations of the ro.sync.ecss.extensions.api.AuthorTableCellSpanProvider and the ro.sync.ecss.extensions.api.AuthorTableColumnWidthProvider interfaces should be provided. The two methods from the ExtensionsBundle specifying these two extension points are createAuthorTableCellSpanProvider and createAuthorTableColumnWidthProvider.
For example:
```
public AuthorTableCellSpanProvider createAuthorTableCellSpanProvider() {
    return new TableCellSpanProvider();
}

public AuthorTableColumnWidthProvider 
    createAuthorTableColumnWidthProvider() {
    return new TableColumnWidthProvider();
}
```
The two table information providers are not reused for different tables. The methods are called for each table in the document so new instances should be provided every time. Read more about the cell span and column width information providers in Configuring a Table Cell Span Provider and Configuring a Table Column Width Provider sections.

If the functionality related to one of the previous extension points does not need to be modified, then the developed ro.sync.ecss.extensions.api.ExtensionsBundle should not override the corresponding method and leave the default base implementation to return null.
[Optional] An XML vocabulary can contain links to various areas of a document. If the document contains elements defined as links, you can choose to present a more relevant text description for each link. To do this, an implementation of the ro.sync.ecss.extensions.api.link.LinkTextResolver interface should be returned by the createLinkTextResolver method. This implementation is used each time the oxy_link-text() function is encountered in the CSS styles associated with an element.
For example:
```
public LinkTextResolver createLinkTextResolver() {
  return new DitaLinkTextResolver();
}
```
Oxygen XML Author Eclipse plugin offers built-in implementations for DITA and DocBook: ro.sync.ecss.extensions.dita.link.DitaLinkTextResolver and ro.sync.ecss.extensions.docbook.link.DocbookLinkTextResolver respectively.
Pack the compiled class into a JAR file.
Copy the JAR file into your custom framework directory (for example, frameworks/sdf).
Add the JAR file to the class path. To do this, open the Preferences dialog box , go to Document Type Association, select the document type (for example, SDF), click the Edit button, select the Classpath tab, and click the Add button. In the displayed dialog box, enter the location of the JAR file relative to the Oxygen XML Author Eclipse plugin frameworks folder.
Register the Java class by going to the Extensions tab. Click the Choose button and select the name of the class (for example, SDFExtensionsBundle).

Note: The complete source code for framework customization examples can be found in the oxygen-sample-framework module of the Oxygen SDK, available as a Maven archetype on the Oxygen XML Author Eclipse plugin website.