Accessing TextGrid Data Structures from your Lab plugin
last modified on Jul 28, 2015
As mentioned before, you will typically just implement Eclipse tooling – see the corresponding documentation and tutorials for that. This section hints at some important concepts to access TextGrid specific data structures in the Lab.
Instead of files and folders, TextGrid uses objects that bundle some
content with a set of metadata. Each object has a TextGrid URI (like
textgrid:47k11.0) that uniquely identifies the object.
In the TextGridLab, there is a data structure called
which represents one of those objects. In one Lab instance, there will
be at most one
TextGridObject per object and there are factory methods
that produce TextGridObjects from URIs, out of the blue, or from
Accessing actual metadata
Each TextGridObject has a
.getMetadata() getter that retrieves a copy
of the metadata and a corresponding setter that updates the object's
makeMetadataPersistent() method can be used to push the
metadata to the repository explicitly, but metadata is also updated
whenever you save the object's contents using the standard methods
There are also some helper methods to deal with specific frequently-used metadata fields.
Accessing an object's content
We offer an object's content in the same way as Eclipse offers access to
files in its workspace: Using Eclipse's
Eclipse makes heavy use of the adapter pattern to convert between
objects. This allows for less tight coupling between classes than
inheritance or common interfaces. It works by using a global adapter
manager which maintains a list of adapter factories that can convert
between objects and convenience methods
adaptableObject.getAdapter(targetClass)) to access this.
Thus, conversion between the layers works by using the adapter pattern as provided by Eclipse.
I.E., if you have a TextGridObject and need an IFile,
/* ... fill textGridObject ... */
IFile file = (IFile) textGridObject.getAdapter(IFile.class);
if (file != null)
/* do something with file */
or vice versa
/* ... fill file ... */
TextGridObject textGridObject = (TextGridObject) file.getAdaptor(TextGridObject.class);
The IFiles have methods for reading and writing and they can also be
passed, e.g., to plain Eclipse editors (by means of a
IFileEditorInput, which is a standard Eclipse interface that can also
be adapted to (and from) directly from TextGridObjects).
Accessing other TextGrid services
info.textgrid.lab.core.model plugin contains APIs for accessing
the basic object and project structure, see the API documentation for details.
If you need to interact directly with TextGrid services, you will find
the respective client libraries in the Lab as well. For TG-search, there is a wrapper and a bunch of utility classes.
You might also look into the UI utilities for, e.g., GUI elements that represent search results.
Configuring TextGrid services, and AAI
If you do not find ready-made client factories in the corresponding wrapper plugins and need to work with the core service APIs, you'll need to provide an endpoint (the address where the service is deployed) and a session id.
The endpoint is available via the Configuration Service.
To get the session id, call RBACSession.getInstance().getSID(boolean).
If you pass
true, this might trigger a login dialog. If the function
returns an empty string, the user has not logged in – passing on the
empty string to functions that require a session id still allows to
access public ressources.