Object Inspector

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The Object Inspector is an OpenOffice.org extension created to help the developer to inspect arbitrary Uno-Objects. As Uno provides a service-oriented API with abstract service descriptions exporting defined interfaces the capabilities of a Uno Object does not open up to the developer at design time mainly due to several "deficiencies". Please note that the Object Inspector is still under development.

The Problem

Generic interfaces like XPropertySet or IndexAccess do not define their exact return value. Service descriptions that export these interfaces mostly do not contain such information either.

It is not always clear at design time which services a UNO object actually supports.

Documentation bugs: as service descriptions do not always show up all actually exported interfaces or properties there may be a certain difference between the theoretical and the practical capabilities of a UNO object.

The Solution

The conclusion is that it has be be inspected during runtime what respective capabilities a Uno-Object actually has. The new Object Inspector is an OpenOffice extension that has been evolved from the ancient instance inspector that is part of the OpenOffice.org SDK. It displays the total capabilities of a „living Uno-object“ such as all supported services, exported interfaces, and their respective methods and properties in a treeview window.


Usage

The object inspector may be installed using the package manager (menu „Tools/Options“) by adding the package from [1] . Together with the new package a new toolbar is added from which the object inspector may be started. The object inspector consists of a menu-controlled resizable dialog with a tab control. Each pane of the tab control contains a split pane whose upper component is occupied by a treeview control embedded in a tab pane (see Illustration 1: Object Inspector). The treeview control is to inspected an arbitrary Uno-object. The bottom component of the split control contains a text control used to display the SourceCode needed to create the Uno-Objects represented by nodes of the treeview control. The initial Uno-Object is the document of the currently active frame. The Uno-object of this document is represented by the root node of the treelist control. Expanding this node will create subnodes referencing all subordinate objects, properties, methods and other values of the root object. All this information is presented in various facettes: Methods of Uno-objects are presented as subnodes under a „Method node“. All methods are listed under this node, no matter what their parental interfaces are. Expanding nodes that denote a method of a Uno-object will invoke the method and if necessary a dialog with an input mask for the method parameters will appear. Note that currently only methods with either no parameters or primitive parameters may be invoked.

Properties of Uno-objects are presented as subnodes under a „Properties“ node.

„Interface“ nodes offer a view to all methods by arranging them under their respective interface.

„Service“ nodes offer a view to all supported services of a Uno-object and their respectively exported interfaces and properties. "Container" nodes may be expanded to retrieve information about Elements. This node is only applicable when the Uno-objects also depicts a container that exports interfaces like "com.sun.star.container.XIndexAccess"

Expanding any arbitrary subnode will inspect the Uno-object that is represented by the node in the same way as described above. Subnodes that describe methods will invoke this method at the Uno-object. If parameters have to be supplied these have to be delivered by the user in a special dialog that opens up when the node is expanded.

The menubar consists of several menus:

  • A „File“ menu to remove tab panes and to quit the object inspector.
  • An „Inspect“ menu in order to determine the Uno-objects to be inspected. Clicking on such a menu item will open a new tab pane for a certain Uno-object. Offered Uno-objects are derived from the following items in this menu:
    • Empty documents of all given application. text document, empty spreadsheet, empty presentation, empty drawing. Selecting one of these menu entries opens a new tabpane and loads an empty hidden application document.
    • Menu entries for each available so-called T-Docs („transient documents“). T-Docs describe the currently opened documents. The object inspector is started with the currently active document as the to-be inspected Uno-object.
    • The currently selected object. This menu entry references the Uno-object of the currently selected node. This option is explicitly helpful in vast object hierarchies where the user can easily loose track.
    • The global service manager, that can be used to instantiate a great variety of services.
  • A„View“ menu: Developers may prefer different views on the respective Uno-Objects depending on the momentary situation and the used programming language. For example StarBasic developers are naturally not very interested what interfaces a Uno object supports as they use the methods directly. On the other hand in StarBasic many „getter“ and „setter“ methods are implemented as properties and should optionally turn up underneath the „Properties“ node. This menu and its underlying functionality has not yet been implementd nor has it been specified.
  • An „Options“menu to be used to set all kind of options. In its current state it is possible to choose the to-be-generated sourcecode language and set the path to a local SDK-installation with contained idl-files (interface and service description files).
  • A „Help“ menu to aquire help about Uno-objects behind selected nodes. Also via shortcut F1 the browser will open a help document about the used interface or service of a Uno-object , that is referenced by a selected node.

A context menu can be applied on selected nodes and offers some functions to 1) inspect the object behind the selected node in a new tabpane 2) add the source code needed to retrieve the Uno-object behind the node to the bottom component of the split pane. 3) get Help to the referred API functionality like via the "Help" menu

Filtering

As can be see in Illustration 1: Object Inspector a filter can assist a determined search for subnodes. It also helps to keep the overview especially in large hierarchies.

File:ObjectInspector.PNG

Illustration 1 Object Inspector

Calling from a Basic Macro

The Object Inspector may be instantiated within a Basic script as can be seen in the following examplary script, where the current document is inspected:

Sub Main
	oInspector = createUnoService("org.openoffice.InstanceInspector")
	oInspector.inspect(ThisComponent, "My Document")
End Sub

Sourcecode generation

The Object Inspector is also able to generate Sourcecode snippets that show how to:

  • query an interface (if necessary in the selected language)
  • invoke a method
  • retrieve a property value

Currently there are Codegenerators for Java, C++, Python and Basic. The resulting code is not perfect, but should compile well.

IDL help

The user may retrieve help about selected nodes from the idl files of the respective interface and service descriptions. As a new feature the Object inspector also offers to provide the path to a local SDK installation when no internet connection is available. To do so follow the menu "Options/SDK-Path" and select the path to the local SDK-installation in the raised folder picker. The path to the SDK-installation is stored persistently.

Known Issues

The Object inspector is still under development and the following list points to some known unresolved defects.

  • The sourcecode generator ignores nodes that do not contain instantiated objects. This is relevant for method nodes: If for some reason an invoked method node delivers a "null" object the source code generator will completey ignore this node.
  • Sourcecode generation below "PropertySetInfo" nodes fail.
  • As the depiction of node images of the treeview control caused problem this feature has been deactivated temporarily.
  • Setting the filter sometimes lead to ArrayIndexOutOfBoundsException.
  • Parameter descriptions of methods node are in the notation of the currently set programming language and not in "Idl" which is not consistant. What makes it worse is that it's not changed when the programming language is changed.
  • When the Idl help document is opened an anchor that represents the method or property name of the selected node should be set (see Sourcecode in class UnoNode; Method openIdlDescription).
  • invoking "getTypes()" creates the following sourcecode: "Type aTypes = xTypeProvider.getTypes();" Return variable should be sequence.
  • The taborder in the „Method-Parameters-Dialog“ does not yet define a cycle. The first focus is not set and when the last control gains the focus the next focus component is not defined.
  • SourceCode generation below container nodes is not yet implemented and will currently raise an exception.
  • exceptions that are declared by methods are not added to the sourcecode. http://www.openoffice.org/issues/show_bug.cgi?id=74280 addresses this problem.
  • After a Node that represents a Uno-object has been expanded it is not checked if subnodes have already been created beforehand.

Future Enhancements

  • Invocation of methods with complex parameters should be implemented. It should be implemented in several steps
    • Implementation of Array parameters with primitive elements. It would be suitable to provide a textfield for this where the elements have to be added comma-separated.
    • Implementation of structs.For each member an own textfield may be provided.
    • Implementation of an input mask to refere to Uno-Objects as method parameters. The reference of the Uno-Objects could be retrieved from the treeviewcontrol and the treepath of a node that represents this Uno-object. This reference must then be added to the method parameter's dialog's respective textfield. It must be considered that this dialog may no longer be modal then and that probably this object also has to be retrieved by invocation of methods (probably with complex parameters).
    • Consider multidimensional arrays as method parameters and for return values.
  • For some method parameters it would be helpful to provide a listbox with all possible values. For example to invoke the method "createInstance(String _sServiceName) a listbox with the return value of "getAvailableServiceNames()" could be offered. Both methods are always provided at the same Uno-Object. Other similar usecases are existent.
  • At some time the whole user interface of the object inspector should be ported to Uno. The user interface has been implemented with Java.Swing, because of some missing functionality in Uno. Yet meanwhile treeview controls may be implemented by Uno, too. Tab controls and menus in Uno dialogs are unfortunately not yet available.
  • Interfaces that are exported by an Uno-Object although not being exported by any of the suported services should be distinguished from the other interfaces. There should be displayed some kind of alert as their usage is potentially hazardous, because it is merely based on an implementation detail.
  • Implementation of different views on the inspected Uno-objects is missing and should be specified.as already being mentioned above in the description of the „View“ menu
  • Property-nodes are queried right after their creation. However their value might change during runtime and for this reason a context menu entry should be provided to explicitly query the node again.

See Also

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