Styling and Data Mapping (SDM)

Describes the SDM package and its subpackages, which are used to define styling and data mapping for the diagram component, but which can also be used to extend its basic functionality.

Presents an overview of the SDM package and its subpackages.

Describes the SDM engine, which controls the data-to-graphics mapping.

Describes the SDM data model, which is the interface that tells the SDM engine how to get the data to be displayed.

Briefly describes renderers, which apply the styles specified in the style sheets.

Defines graphers, which can store graphic objects including general nodes, composite nodes, and general links. They provide the infrastructure that is minimally necessary to draw a graph.

Describes interactors, which support the interaction between a user and a diagram.

The SDM package ilog.views.sdm and its subpackages contain the styling and data mapping (SDM) classes. These classes are usually used internally by the diagram component, but you may need to use these classes directly to extend its basic functionality.

The main entry point to the package is the class IlvSDMEngine. See the following diagram.

The SDM subpackages are:

ilog.views.sdm.graphic: The specialized SDM graphic objects such as graphic factories and the general node.

ilog.views.sdm.interactor: The interactor-related classes.

ilog.views.sdm.model: The predefined classes for data models.

ilog.views.sdm.renderer and ilog.views.sdm.renderer.animation: The classes that define the renderers available for styling. Other renderer subpackages are:

ilog.views.sdm.renderer.graphlayout: The classes that configure the Graph Layout capability, if you have purchased a full JViews Diagrammer license.

ilog.views.sdm.renderer.maps: The classes that provide access to the Maps product, if you have purchased it.

ilog.views.sdm.servlet: A specialized servlet that gives easy access to styling and data mapping in thin-client mode.

ilog.views.sdm.swing: The JFC/Swing-based components for building a full GUI.

The SDM engine controls the data-to-graphics mapping.

There are four key elements in the data-to-graphics mapping process:

A data model that interfaces to the data to display or edit. This data model is completely independent of the GUI, and refers only to the business objects of your application.

Renderers that style the diagram as a whole and the graphic objects in it.

A grapher in which the graphic objects representing the data model are created.

As shown in the above figure, the mapping between the data model and the graphical representation is bidirectional:

1. Data model to graphics: the rendering process is controlled by the style sheet, which lets you tell the SDM engine how you want each particular kind of data object to be displayed in the grapher. The rendering process is performed by specialized renderers.

When the data model is loaded, the SDM engine explores it and creates graphic objects representing the nodes and links defined by the data model in the grapher.

When the state of an object in the data model changes, the SDM engine updates the graphic object representing the modified data object. The object state may change due to an external application event or after a direct edit of an object property by the user.

2. Graphics to data model: the editing process relies on built-in editing facilities that act directly on the underlying data model. The actions in an editing application are implemented by interactors. For example:

When the user moves a graphic object (for example, in an editor), the SDM engine updates the geometric properties of the object in the data model.

When the user expands or collapses a node (for example, in a navigation application), the SDM engine updates the expand/collapse status of the object in the data model.

To access the SDM engine associated with a diagram component, use the getEngine method. Similarly, to access the SDM view associated with a diagram component, use the getView method. The following code example shows the use of these methods.

You can also choose not to use the IlvDiagrammer class at all. Instead, you can create an SDM engine ( IlvSDMEngine instance) and an SDM view ( IlvSDMView instance) yourself.

The SDM data model is the interface that tells the SDM engine how to get the data to be displayed. The SDM data model is an abstract description of a set of nodes and links between nodes. Nodes and links have a user-defined type (also called the “tag”), and a set of named properties.

A default data model is supplied as class IlvDefaultSDMModel and you can also develop your own data model.

The classes provided for data models are in the package ilog.views.sdm.model.

For a discussion of the available data model classes and advice on writing your own, see Using and writing data models.

Renderers apply the styles specified in the style sheets. They have global properties for styling the diagram and per-object properties for styling the objects in the diagram.

The predefined renderers for styling graphic objects are described in Using and adding renderers.

That section also provides an example of adding your own renderer.

Graphers can store graphic objects including general nodes, composite nodes, and general links. They provide the infrastructure that is minimally necessary to draw a graph.

A grapher ( IlvGrapher instance) is a JViews Framework object created by the IlvDiagrammer instance. You may need to access the grapher to modify the graphic objects of the diagram directly. The following code example shows how to access the grapher.

For more details on graphers, see Graphers in The Essential JViews Framework.

Interactors support the interaction between a user and a diagram. Common requirements are for zoom, pan, select, and object creation functions.

The predefined interactors are described in Using and writing interactors.

That section also provides an example of adding your own interactor.