Hi Nathan,

I'm sorry I didn't give more details. I kind of expected our documentation to also mention more on how to install the filter, but at a closer look I see that it doesn't... I'll add an issue to add more details.

There are two places where you can add the filter:
1. AuthorExtensionStateListener.activated(), if you are working with framework level API. Like you've said, you can create a class which extends the DITAExtensionBundle and override createAuthorExtensionStateListener(). I recommend also delegating to the super listener (the default bundle needs this listener too), like so:

public class CustomDITAExtensionBundle extends DITAExtensionsBundle {
  /**
   * @see ro.sync.ecss.extensions.dita.DITAExtensionsBundle#createAuthorExtensionStateListener()
   */
  @Override
  public AuthorExtensionStateListener createAuthorExtensionStateListener() {
    final AuthorExtensionStateListener superListener = super.createAuthorExtensionStateListener();
   
    return new AuthorExtensionStateListenerDelegator() {
      @Override
      public String getDescription() {
        return "";
      }
      @Override
      public void deactivated(AuthorAccess authorAccess) {
        superListener.deactivated(authorAccess);
      }
     
      @Override
      public void activated(AuthorAccess authorAccess) {
        // TODO INSTALL FILTER
        authorAccess.getDocumentController().setDocumentFilter(authorDocumentFilter);
        superListener.activated(authorAccess);
      }
    };
  }
}

2. An Workspace Access plugin [2], if you are working with plugin API. Like so:

  public void applicationStarted(final StandalonePluginWorkspace pluginWorkspaceAccess) {
   
    pluginWorkspaceAccess.addEditorChangeListener(
        new WSEditorChangeListener() {
          @Override
          public void editorOpened(URL editorLocation) {
            WSEditor editorAccess = pluginWorkspaceAccess.getEditorAccess(editorLocation, PluginWorkspace.MAIN_EDITING_AREA);
            WSEditorPage currentPage = editorAccess.getCurrentPage();
            if (currentPage instanceof WSAuthorEditorPage) {
              WSAuthorEditorPage authorEditorPage = (WSAuthorEditorPage) currentPage;
              authorEditorPage.getAuthorAccess().getDocumentController().setDocumentFilter(authorDocumentFilter);
            }
            // TODO It's also a good idea to listener for page changes on the editor.
            // Perhaps the editor opens in the text page and the user switches later on to author.
            editorAccess.addPageChangedListener(new WSEditorPageChangedListener() {
              @Override
              public void editorPageChanged() {
                // TODO Same code here to add the filter.
              }
            });
          }
        },
        PluginWorkspace.MAIN_EDITING_AREA);


[1] http://www.oxygenxml.com/InstData/Editor/SDK/javadoc/ro/sync/ecss/extensions/api/AuthorExtensionStateListener.html
[2] http://www.oxygenxml.com/doc/ug-editor/#concepts/workspace-access-plugin.html

Best regards,
Alex
-- 
Alex Jitianu
<oXygen/>  XML Editor, Schema Editor and XSLT Editor/Debugger
http://www.oxygenxml.com 

On 06-May-14 8:50 AM, Nathan wrote: