COMPOSITE APPLICATIONS - DESIGN AND MANAGEMENT
Components within a composite application can be wired to together so a user-initiated action in one component can trigger a programmed action in another component. This functionality is supported by the use of properties, actions, types, and the property broker. The composite application components use a model for declaring, publishing, and sharing this information with each other via the WebSphere Portal property broker.
Components subscribe to the broker by publishing typed data items - properties and actions - that they can share. Components can act either as a provider or as a recipient of these properties and actions.
These components may be developed and deployed separately or together and can exchange information and react in a coordinated manner, thus improving the end-user experience. Conversely, as components are removed, the remaining components will still be able to function correctly and in a coordinated manner. The property broker is used to facilitate development of components that may be dynamically integrated, without requiring previous coordination at development time. Composite applications can simply be an assembly of multiple components with on-the-glass aggregation that keep the application user focused on the business process, eliminating the need for the application user to switch between applications or switch between open windows.
To derive additional value and further increase organizational productivity, you can have components form causal relationships with other components through properties and actions. A property broadcasts a value and an action consumes a value. In order to make sure that both sides are communicating consistently, both properties and actions need to describe the type of value they broadcast or consume. This ensures that sensible connections are made when the components are wired together.
Using the Property Broker Editor feature
WSDL files that are used in composite applications are created and edited in IBM® Lotus® Domino(TM) Designer using the Property Broker Editor feature.
This feature provides an easy way for you to describe property broker properties, actions, and types without having to understand the WSDL format. You define the properties, actions, and types through a simple interface which then generates the WSDL file required by property broker implementations when you save the editor settings.
This feature lets you do the following:
Defining properties for composite applications
With composite applications, you need to define the properties that portlets will use to exchange information using the IBM® WebSphere® Portal property broker. The property broker transfers instances of these properties and their values to and from portlets to initiate actions.
The property broker is a WebSphere Portal interface that negotiates the relationship between cooperative source and target portlets and delivers data to the target in the form of the corresponding portlet action. For more information about the WebSphere Portal property broker, go to http://www.ibm.com/websphere/portal/library.
To define properties and their corresponding property details with the Domino Designer Property Broker Editor feature, do the following:
1. Start Domino Designer
2. Open the composite application that contains the WSDL file that you wish to open.
3. Click Composite Applications-Wiring Properties. The WSDL files for the composite application are displayed in the Composite Applications-Wiring Properties view.
4. Select the file that you wish to open for editing.
5. Click the Open File button. The Property Broker Editor feature is launched so that you can edit your WSDL file.
6. Click the Properties tab in the canvas. A form titled Wiring Properties is displayed.
7. In the Wiring Properties form, do the following:
Note Optional: In the Description field of the Property Details box, type a description of the property. Your administrator uses this description when wiring the portlets after deployment.
As a result, Domino Designer creates a Web Services Description Language (WSDL) file so that your component can reference the properties. This file will be deployed to WebSphere Portal along with the rest of the component files.
If you are editing an existing WSDL file, you need to refresh the existing Wiring Properties design element to update it with your changes. Refer to the topic "Updating or refreshing an edited WSDL file in Domino Designer" for more information on refreshing and updating your Wiring Properties design element.
Defining property data types for composite applications
With composite applications, properties are used to exchange information between application components using the IBM® WebSphere® Portal property broker. The property broker transfers instances of these properties and their values to and from portlets to initiate actions.
The property broker is a WebSphere® Portal interface that negotiates the relationship between cooperative source and target portlets and delivers data to the target in the form of the corresponding portlet action. For more information about the WebSphere Portal property broker, go to http://www.ibm.com/websphere/portal/library.
Use the following steps to set data types for these properties:
6. Click the Types tab in the editor. Any new types that you create on the Types page appear in the Type list on the Properties page.
Note In most cases, the property type is string. Normally, you only set new property types for properties that contain multiple types, for example, string, integer, and date/time.
7. To create a new property type, do either of the following steps:
10. Click File > Save to save your all your new types and changes.
Below the Types section of the form, there is the Type Namespaces section. By default, this section is collapsed. It can be opened by clicking on the Type Namespaces text. This section is provided to help eliminate namespace typing errors when adding namespaces and it also lets you assign a prefix to that type since the Namespace field in the Type Details section is non-editable and only lets you choose from valid namespaces understood by the component.
Within the Type Namespaces section, you can add a namespace with a prefix to refer to types, perhaps from another component, or another external standard. Click Add to add a new namespace. Enter the new prefix in the Prefix field and the desired namespace in the Namespace field. To remove a type namespace, select the one you wish to remove from the list on the left and click Remove.
Creating actions and action parameters for composite applications
With composite applications, you need to define the actions that are triggered when portlets publish properties that get received by another portlet. Examples of actions include changing or refreshing component pages and redirecting the current page to a Web site.
In composite applications, the following steps must take place before an action can occur.
6. Click the Actions tab in the canvas. A form titled Wiring Actions is displayed.
7. In the Wiring Actions form, do the following:
If you wish to change these options, de-select the option to disable it.
Note Optional: In the Description field of the Action details box, type a description of the action. Your administrator uses this description when wiring the portlets after deployment.
You must now define the following for your action(s):
Action Input Parameter
An Action Input Parameter is used to identify that an action is associated with an input property. This action is triggered when the input property is published - provided it is active. You would then use the value in a script to update whatever information on the page is dependent on the value.
You set the Action input Parameter by specifying the associated input property in the Property field of the Action Input Parameter section of the Wiring Actions form. Your action is then triggered in response to this property being published, and when this action is invoked, the value of this property can be requested by script.
Action Output Parameter
If an action publishes a property, you need to define an action output parameter. You can do this by using the Available Properties and Selected Properties boxes in the Action Output Parameter section of the Wiring Actions form .
The Available Properties box lists all the properties in the current WSDL file - that have not already been chosen as output properties. You can select one or more properties and click Add to set them as output parameters for the current action.
The Selected Properties box lists the properties that have been chosen as output parameters for the current action.
You can then use the Add and Remove buttons to set and unset output parameters from the Available Properties list.
Be sure to click File > Save to save all your Action Input and Output Parameter changes.
See Also