Getting Folders

The Documents and Media API can get folders in a similar way to getting files. The main difference is that folder retrieval methods may have an additional argument to tell the system whether to include mount folders. Mount folders are mount points for external repositories (e.g. Alfresco or SharePoint) that appear as regular folders in a Site’s default repository. They let users navigate seamlessly between repositories. To account for this, some folder retrieval methods include the boolean parameter includeMountFolders. Setting this parameter to true includes mount folders in the results, while omitting it or setting it to false excludes them.

For example, to get a list of a parent folder’s subfolders from a repository, including any mount folders, use the getFolders method:

getFolders(long repositoryId, long parentFolderId, boolean includeMountFolders)

Follow these steps to use this method to get the folders from a parent folder. Note that the example in these steps gets the folders in the default Site repository’s root folder:

1. Get a reference to DLAppService:

   @Reference
   private DLAppService _dlAppService;
   

   For more information on this, see the section on getting a service reference in the getting started tutorial.

2. Get the data needed to populate the method’s arguments any way you wish. This getFolders method needs a repository ID, a parent folder ID, and a boolean value that indicates whether to include mount folders in the results. To specify the default site repository, you can use the group ID as the repository ID. This example gets the group ID from the request (javax.portlet.ActionRequest) via ParamUtil:

   long groupId = ParamUtil.getLong(actionRequest, "groupId");
   

   It’s also possible to get the group ID via the ThemeDisplay. Calling the ThemeDisplay method getScopeGroupId() gets the ID of your app’s current site (group). For more information, see the Data Scopes tutorial.

   ThemeDisplay themeDisplay = (ThemeDisplay) request.getAttribute(WebKeys.THEME_DISPLAY);
   long groupId = themeDisplay.getScopeGroupId();
   

   Note that getting the parent folder ID isn’t necessary because this example uses the root folder, for which Liferay DXP provides a constant. Also, the boolean value can be provided directly—it doesn’t need to be retrieved from somewhere. For more information on getting repository and folder IDs, see the getting started tutorial’s sections on specifying repositories and folders.

3. Call the service reference’s getFolders method with the data from the previous step and any other values you want to provide. Note that this example uses DLFolderConstants.DEFAULT_PARENT_FOLDER_ID to specify the repository’s root folder as the parent folder. It also uses true to include any mount folders in the results:

   _dlAppService.getFolders(groupId, DLFolderConstants.DEFAULT_PARENT_FOLDER_ID, true)
   

Note that this is one of many methods you can use to get folders. The rest are listed in the DLAppService Javadoc.

Related Topics

Getting Started with the Documents and Media API

Getting Files

Getting Multiple Entity Types

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