Tooling support for events and public render parameters for portal and portlet applications
2009-09-11 01:43
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Key concepts
The key concepts of this article are explained first, and then these
concepts are illustrated by using a sample portlet application.
Events
Version 2 of the Java™ Specification Request (JSR) 286 specification
makes it possible for portlets to send and receive events. Events
permit the portlets to communicate with each other. IBM® Rational®
Application Developer Version 7.5 provides a set of tools to define
events, enable the portlets, and pass data between them by using
events. A portlet can handle both ends of communication:
Send events to other portlets
Receive and process events from other portlets
Attributes of events
Each event must have a name and, possibly, other attributes:
Name:
A unique name for the event. The event name can be a
full QName, a qualified name as defined in the XML specification,
consisting of a namespace (for example, http://www.ibm.com) and a local
part (for example, sampleEvent). Alternatively, you can use the same
namespace for many events by declaring it as the default namespace and
then specifying only the local part for each event.
Description:
(Optional) A description of the event.
Value type:
(Optional) A fully qualified Java class name of the value to be transferred with the event.
Alias:
(Optional) A namespace-qualified name for the event.
To create a portlet application that incorporates events and public
render parameters for communication between portlets, complete these
tasks:
Create a JSR 286 portlet project and portlets.
Create an event definition in the portlet deployment descriptor (PDD).
Add the event as a supported publishing or a processing event by the portlet.
Modify the process action or event code in the portlet class to publish or process the event.
Add the public render parameters.
Publish the portlet project to the server.
Wire the portlets together.
These tasks are greatly simplified by using the tools provided by Rational Application Developer V7.5.
Public render parameters
The JSR 286 specification provides another mechanism that enables coordination between portlets: public render parameters
(see Resources for where to find out more about them). These parameters
provide a way to share request parameters across portlets.
Attributes of public render parameters
Each parameter must have a name and possibly other attributes:
Name:
(Required) A unique name for the parameter, either a
string or namespace-qualified name. Select the default namespace or
specify a different one. The localized string that you entered as the
event name is appended to the namespace.
Identifier:
(Required) A string used in the portlet code to refer to the render parameter.
Description:
(Optional) A description of the render parameter.
Alias:
(Optional) A namespace-qualified name for the parameter.
Back to top
Sample application used in this article
In this article, a sample portlet application demonstrates the
usefulness of the events and public render parameter features of JSR
286. The sample application is used by a shipping company to maintain
the details of its orders and customers. It consists of three portlets:
The Orders portlet maintains the monthly details of the orders of the company.
The OrderDetails portlet shows the details of one order.
The TrackingDetails portlet shows the tracking details of one order.
The article demonstrates how to create events and public render parameters and use them in the sample. See Download
to get the complete sample.
The use case for the sample
A user can select an order ID of a month to view its order and
tracking details. This is implemented by using events and public render
parameters. The Orders portlet summarizes information for all of the
orders over a month. When the user clicks the ID for an order in the
Orders portlet, the portlet triggers an event. This event is processed
by the OrderDetails portlet that shows the order details for the
selected order ID. The OrderDetails portlet then fetches the tracking
ID of the order from the order details, and passes the details to the
TrackingDetails portlet as a render parameter. The TrackingDetails
portlet then shows the tracking details of that order.
To make this use case work, use the Portal Toolkit in Rational Application Developer 7.5 to first declare an event called
.
This event is added as a supported publishing event for the Orders
portlet and as a supported processing event for the OrderDetails
portlet.
You then create the
public render parameter and make the OrderDetails and TrackingDetails portlets support the parameter.
Back to top
Create the JSR 286 portlet project and portlets
The Portlet Project wizard in Rational Application Developer supports the creation of JSR 286-compliant portlet projects.
To create the portlet project:
Click File > New > Portlet Project
to open the wizard.
Specify the details, as shown in Figure 1:
For the target runtime environment, select WebSphere Portal v6.1
.
For the portlet API, select JSR 286 Portlet
.
For the portlet type, select Basic Portlet
.
Figure 1. JSR 286 portlet project creation wizard
The next step is to add the required portlets to the portlet
application that you created. Given that the article covers three
portlets in the sample application, you can add these portlets to the
portlet project (see Figure 2):
Right-click the portlet deployment descriptor and select New > Portlet
.
Enter the portlet name as
, and click Finish
.
Repeat these steps to add the other two portlets: OrdersPortlet and TrackingPortlet.
Figure 2. Portlet creation wizard
Note:
This article does not discuss how to modify the
Java™Server Pages (JSP™) files and add the function that you want to
the portlets, because the focus is on creating events and public render
parameters. The assumption is that the portlets have been modified,
with the Orders portlet showing the orders for the month, the
OrderDetail portlet showing the order details, and the Tracking portlet
showing the tracking details of the order.
Figure 3 shows how the OrdersPortlet will look when it is published on WebSphere Application Server V6.1.
Figure 3. Orders Portlet
Back to top
Create an event definition in the portlet deployment descriptor
It is easy to create events with the event wizard included in Rational Application Developer. To create the three events:
Expand the portlet project in the Project Explorer.
Right-click the portlet deployment descriptor and select Event
.
As Figure 4 shows, two options are available under Event:
Enable this Portlet to Publish Event
Enable this Portlet to Process Event
Figure 4. Events options
Click to enlarge
Back to top
Add the event as a portlet publishing event
These actions are performed when you select the first option, which is "Enable this Portlet to Publish Event:"
Add the event definition to the portlet application
Add the event as a supported publishing event for the portlet
Modify either the
or
methods to publish the event
These options are performed when you select the other option, "Enable this Portlet to Process Event:"
Add the event definition to the portlet application, if this event definition does not yet exist
Add the event as a supported processing event to the portlet
Modify the processEvent()methods to process the event
The next step is to create the event by using the wizard. To enable the Orders portlet to publish the OrderIDType event:
Right-click the Orders
portlet under the portlet deployment descriptor.
Select Event > Enable this Portlet to Publish events
. This action opens the wizard.
Specify the details, as in Figure 5:
For the Event name, select OrderIDType
.
For the Value type, specify String
.
Figure 5. Wizard to enable a portlet to publish events
Click Finish
.
This wizard makes two changes to the portlet deployment descriptor:
Adds the event definition to the portlet application
Adds the event as a supported published event for the portlet
The code in bold in Listing 1 shows how the portlet deployment descriptor code is modified by the event wizard.
Listing 1. Deployment descriptor code modifications
Back to top
Modify the process action code in the portlet class to publish the event
The
method is then modified to publish the event, as Listing 2 shows.
Listing 2. Modifications to the processAction( ) event
You must customize the code that is generated by the event wizard to
fit your requirement. Because the OrderIDType needs to be sent, the
order ID comes from the action request parameter when the order ID is
selected (see Listing 3).
Listing 3. Code to send the OrderIDType
The wizard modifies the portlet under the portlet deployment
descriptor, as shown in the Project Explorer in Figure 6. Under the
OrdersPortlet node, the OrderIDType event appears.
Figure 6. Project Explorer
Add the event as a processing event supported by the portlet
Next, the order ID needs to be received by the OrderDetail portlet.
In other words, the event that was published now needs to be processed
by the OrderDetail portlet.
To enable the portlet to process the event:
Expand the Portlet Deployment Descriptor
node.
Right-click the OrderDetail
portlet and select Event > Enable this Portlet to Process Event
.
Figure 7. The process events option
Click to enlarge
The "Enable this portlet to process events" wizard opens, as shown in Figure 8.
Figure 8. Enable this Portlet to Process events window
For the Event Name, select OrderIDType
, which has already
been declared using the event publishing wizard. You cannot modify the
event definition here, but you can edit it manually in the portlet
deployment descriptor.
Click Finish
to complete this processing:
Add the
element for the OrderDetail Portlet (you already added the event definition when you published this event)
Modify the
method to process the event
The portlet section for the OrderDetail portlet is modified as Listing 4 shows.
Listing 4. Modifications to the OrderDetail portlet
Modify the event code in the portlet class to process the event
As Listing 5 shows, changes are also made to the
method that is responsible for processing the event that is received.
Listing 5. Modifications to the processEvent( ) method
You need to send the TrackingIDfrom the OrderDetail portlet to the Tracking portlet. Therefore, you need to modify the
method, as the code in bold in Listing 6 shows.
Listing 6. Modifications to the processEvent( ) method
For the OrderDetails Portlet to show the Order Details, you need to modify the
method to add the code that Listing 7 shows in bold.
Listing 7. Modifications to the doView( ) method
Back to top
Add the public render parameters
The next step is to use the public render parameter mechanism to
share the tracking ID between the OrderDetail portlet and the Tracking
portlet:
Open the portlet deployment descriptor for the EventSample project.
Select the Render Params
tab, and then click Add
to create a public render parameter with the default name, NewPublicRenderParam.
Change the Name and Identifier fields to
, as shown in Figure 9.
Figure 9. Render Params tab in the Portlet Deployment Descriptor editor
Click to enlarge
This action adds the section shown in Listing 8 to the portlet application definition of the portlet deployment descriptor.
Listing 8. Code snippet added to the portlet deployment descriptor
Because this parameter needs to be shared by the Tracking and
OrderDetail portlets, you need to add it as a supported public render
parameter for each of those portlets.
From the Portlets tab, select the Tracking
portlet.
Scroll down to the Supported Public Render Parameters section in the right pane, and click Select
.
For the name, select Tracking ID
, which was created in the Render Params tab in the editor, as shown in Figure 10.
Click OK
.
Repeat Steps 4 and 5 to add
as a supported public render parameter for the OrdersPortlet.
Figure 10 shows the public render parameter added to the portlets.
Figure 10. Supported public render parameter added
Click to enlarge
The changes shown in bold in Listing 9 are made to the portlet deployment descriptor.
Listing 9. Modifications to the portlet deployment descriptor
You must modify the
method of the Tracking portlet to display the tracking details, based on the TrackingIDof the order (see Listing 10).
Listing 10. Modifications for the doView( ) method
Back to top
Publish the portlet project
Now you can publish the portlet application on WebSphere Application Server V6.1:
Right-click the portlet project (see Figure 11) and select Run As > Run on Server
.
Figure 11. Publish the portlet project
Click to enlarge
Select the WebSphere Portal V6.1 Server
, as in Figure 12.
Click Next
, and then click Finish
.
Figure 12. Select the server where you want to run your portlet application
Back to top
Wire the portlets together
The wiring tool that is available on the portal server can help you
wire the relationships between portlets that share events between them.
To access the wiring tool:
Select Edit Page Layout
for the page on which the portlets are placed.
Select the Wires
tab.
For the source portlet, select OrdersPortle
t from the drop-down menu, and for the target portlet, select the OrderDetail
portlet (Figure 13). For the event names, click the drop-down arrow for the Sending
and Receiving
fields.
Figure 13. Add wires to define the relationships in the portlet application
Click to enlarge
Click the plus sign and then click Done
.
Select an order ID (for example, the first one in the OrdersPortlet).
When you click the order ID, an event is triggered by the Orders
portlet, which sends the Order_ID value to the Order Details portlet.
When that portlet receives the order ID, the Order Details Portlet
processes the event. It fetches the details of the order ID and
displays them for the user. In addition, the Order Details portlet
retrieves the tracking ID for the order and communicates the ID to the
tracking details portlet, because the TrackingIDhas been added as a
shared render parameter for both the Order Details and Tracking
portlets. Thus, once the user clicks on an order ID, the order details
and the tracking details are shown to the user (see Figure 14).
Figure 14. The Orders portlet
The user can now see the order and tracking details, as Figure 15
shows. Thus, events and public render parameters are used to transfer
the OrderID and the TrackingIDto the respective portlets.
Figure 15. Order and Tracking detail portlets
Click to enlarge
As you have seen here, the tools provided by Rational Application
Developer 7.5 greatly simplify the creation of events and public render
parameters. You need to customize only the code that is generated to
fit the requirements of your application.
Back to top
Download
Information about download methods
Resources
Learn
Learn What's new in the Java Service Specification V2.0 JSR 286) for portlets
.
Read What's new in IBM WebSphere Portal V6.1: JSR 286 features
to learn how the concepts of the new standards, particularly
interportlet communication, have been integrated and get guidelines for
choosing between using portlet events or public render parameters for
communication.
Find out more about public render parameters
, which enable JSR 286 portlets to share navigational state information.
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for technical resources and best practices for Rational Software Delivery Platform products.
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The key concepts of this article are explained first, and then these
concepts are illustrated by using a sample portlet application.
Events
Version 2 of the Java™ Specification Request (JSR) 286 specification
makes it possible for portlets to send and receive events. Events
permit the portlets to communicate with each other. IBM® Rational®
Application Developer Version 7.5 provides a set of tools to define
events, enable the portlets, and pass data between them by using
events. A portlet can handle both ends of communication:
Send events to other portlets
Receive and process events from other portlets
Attributes of events
Each event must have a name and, possibly, other attributes:
Name:
A unique name for the event. The event name can be a
full QName, a qualified name as defined in the XML specification,
consisting of a namespace (for example, http://www.ibm.com) and a local
part (for example, sampleEvent). Alternatively, you can use the same
namespace for many events by declaring it as the default namespace and
then specifying only the local part for each event.
Description:
(Optional) A description of the event.
Value type:
(Optional) A fully qualified Java class name of the value to be transferred with the event.
Alias:
(Optional) A namespace-qualified name for the event.
To create a portlet application that incorporates events and public
render parameters for communication between portlets, complete these
tasks:
Create a JSR 286 portlet project and portlets.
Create an event definition in the portlet deployment descriptor (PDD).
Add the event as a supported publishing or a processing event by the portlet.
Modify the process action or event code in the portlet class to publish or process the event.
Add the public render parameters.
Publish the portlet project to the server.
Wire the portlets together.
These tasks are greatly simplified by using the tools provided by Rational Application Developer V7.5.
Public render parameters
The JSR 286 specification provides another mechanism that enables coordination between portlets: public render parameters
(see Resources for where to find out more about them). These parameters
provide a way to share request parameters across portlets.
Attributes of public render parameters
Each parameter must have a name and possibly other attributes:
Name:
(Required) A unique name for the parameter, either a
string or namespace-qualified name. Select the default namespace or
specify a different one. The localized string that you entered as the
event name is appended to the namespace.
Identifier:
(Required) A string used in the portlet code to refer to the render parameter.
Description:
(Optional) A description of the render parameter.
Alias:
(Optional) A namespace-qualified name for the parameter.
Back to top
Sample application used in this article
In this article, a sample portlet application demonstrates the
usefulness of the events and public render parameter features of JSR
286. The sample application is used by a shipping company to maintain
the details of its orders and customers. It consists of three portlets:
The Orders portlet maintains the monthly details of the orders of the company.
The OrderDetails portlet shows the details of one order.
The TrackingDetails portlet shows the tracking details of one order.
The article demonstrates how to create events and public render parameters and use them in the sample. See Download
to get the complete sample.
The use case for the sample
A user can select an order ID of a month to view its order and
tracking details. This is implemented by using events and public render
parameters. The Orders portlet summarizes information for all of the
orders over a month. When the user clicks the ID for an order in the
Orders portlet, the portlet triggers an event. This event is processed
by the OrderDetails portlet that shows the order details for the
selected order ID. The OrderDetails portlet then fetches the tracking
ID of the order from the order details, and passes the details to the
TrackingDetails portlet as a render parameter. The TrackingDetails
portlet then shows the tracking details of that order.
To make this use case work, use the Portal Toolkit in Rational Application Developer 7.5 to first declare an event called
OrderIDType
.
This event is added as a supported publishing event for the Orders
portlet and as a supported processing event for the OrderDetails
portlet.
You then create the
TrackingIDType
public render parameter and make the OrderDetails and TrackingDetails portlets support the parameter.
Back to top
Create the JSR 286 portlet project and portlets
The Portlet Project wizard in Rational Application Developer supports the creation of JSR 286-compliant portlet projects.
To create the portlet project:
Click File > New > Portlet Project
to open the wizard.
Specify the details, as shown in Figure 1:
For the target runtime environment, select WebSphere Portal v6.1
.
For the portlet API, select JSR 286 Portlet
.
For the portlet type, select Basic Portlet
.
Figure 1. JSR 286 portlet project creation wizard
The next step is to add the required portlets to the portlet
application that you created. Given that the article covers three
portlets in the sample application, you can add these portlets to the
portlet project (see Figure 2):
Right-click the portlet deployment descriptor and select New > Portlet
.
Enter the portlet name as
OrderDetail
, and click Finish
.
Repeat these steps to add the other two portlets: OrdersPortlet and TrackingPortlet.
Figure 2. Portlet creation wizard
Note:
This article does not discuss how to modify the
Java™Server Pages (JSP™) files and add the function that you want to
the portlets, because the focus is on creating events and public render
parameters. The assumption is that the portlets have been modified,
with the Orders portlet showing the orders for the month, the
OrderDetail portlet showing the order details, and the Tracking portlet
showing the tracking details of the order.
Figure 3 shows how the OrdersPortlet will look when it is published on WebSphere Application Server V6.1.
Figure 3. Orders Portlet
Back to top
Create an event definition in the portlet deployment descriptor
It is easy to create events with the event wizard included in Rational Application Developer. To create the three events:
Expand the portlet project in the Project Explorer.
Right-click the portlet deployment descriptor and select Event
.
As Figure 4 shows, two options are available under Event:
Enable this Portlet to Publish Event
Enable this Portlet to Process Event
Figure 4. Events options
Click to enlarge
Back to top
Add the event as a portlet publishing event
These actions are performed when you select the first option, which is "Enable this Portlet to Publish Event:"
Add the event definition to the portlet application
Add the event as a supported publishing event for the portlet
Modify either the
processAction()
or
processEvent()
methods to publish the event
These options are performed when you select the other option, "Enable this Portlet to Process Event:"
Add the event definition to the portlet application, if this event definition does not yet exist
Add the event as a supported processing event to the portlet
Modify the processEvent()methods to process the event
The next step is to create the event by using the wizard. To enable the Orders portlet to publish the OrderIDType event:
Right-click the Orders
portlet under the portlet deployment descriptor.
Select Event > Enable this Portlet to Publish events
. This action opens the wizard.
Specify the details, as in Figure 5:
For the Event name, select OrderIDType
.
For the Value type, specify String
.
Figure 5. Wizard to enable a portlet to publish events
Click Finish
.
This wizard makes two changes to the portlet deployment descriptor:
Adds the event definition to the portlet application
Adds the event as a supported published event for the portlet
The code in bold in Listing 1 shows how the portlet deployment descriptor code is modified by the event wizard.
Listing 1. Deployment descriptor code modifications
<?xml version="1.0" encoding="UTF-8"?> <portlet-app xmlns="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd" version="2.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd" id="com.ibm.jsr286eventrenderparam.JSR286EventRenderParamPortlet.19a07d46c1"> <portlet> <portlet-name>OrderDetail</portlet-name> <?xml version="1.0" encoding="UTF-8"?> <portlet-app xmlns="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd" version="2.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd" id="com.ibm.jsr286eventrenderparam.JSR286EventRenderParamPortlet.19a07d46c1"> <portlet> <portlet-name>OrderDetail</portlet-name> <display-name xml:lang="en">OrderDetail</display-name> <display-name>OrderDetail</display-name> <portlet-class> com.ibm.jsr286eventrenderparam.OrderDetailPortlet </portlet-class> <init-param> <name>wps.markup</name> <value>html</value> </init-param> <expiration-cache>0</expiration-cache> <supports> <mime-type>text/html</mime-type> <portlet-mode>view</portlet-mode> </supports> <supported-locale>en</supported-locale> <resource-bundle> com.ibm.jsr286eventrenderparam.nl.OrderDetailPortletResoure </resource-bundle> <portlet-info> <title>OrderDetail</title> <short-title>OrderDetail</short-title> <keywords>OrderDetail</keywords> </portlet-info> </portlet> <portlet> <portlet-name>OrdersPortlet</portlet-name> <display-name xml:lang="en">OrdersPortlet</display-name> <display-name>OrdersPortlet</display-name> <portlet-class> com.ibm.jsr286eventrenderparam.OrdersPortlet </portlet-class> <init-param> <name>wps.markup</name> <value>html</value> </init-param> <expiration-cache>0</expiration-cache> <supports> <mime-type>text/html</mime-type> <portlet-mode>view</portlet-mode> </supports> <supported-locale>en</supported-locale> <resource-bundle> com.ibm.jsr286eventrenderparam.nl.OrdersPortletResource </resource-bundle> <portlet-info> <title>OrdersPortlet</title> <short-title>OrdersPortlet</short-title> <keywords>OrdersPortlet</keywords> </portlet-info> <supported-publishing-event> <name>OrderIDType</name> </supported-publishing-event> </portlet> <portlet> <portlet-name>TrackingPortlet</portlet-name> <display-name xml:lang="en">TrackingPortlet</display-name> <display-name>TrackingPortlet</display-name> <portlet-class> com.ibm.jsr286eventrenderparam.TrackingPortlet </portlet-class> <init-param> <name>wps.markup</name> <value>html</value> </init-param> <expiration-cache>0</expiration-cache> <supports> <mime-type>text/html</mime-type> <portlet-mode>view</portlet-mode> </supports> <supported-locale>en</supported-locale> <resource-bundle> com.ibm.jsr286eventrenderparam.nl.TrackingPortletResource </resource-bundle> <portlet-info> <title>TrackingPortlet</title> <short-title>TrackingPortlet</short-title> <keywords>TrackingPortlet</keywords> </portlet-info> </portlet> <default-namespace>http://JSR286EventRenderParam/</default-namespace> <event-definition> <name>OrderIDType</name> <value-type>java.lang.String</value-type> </event-definition> </portlet-app> |
Modify the process action code in the portlet class to publish the event
The
processAction()
method is then modified to publish the event, as Listing 2 shows.
Listing 2. Modifications to the processAction( ) event
public void processAction
(ActionRequest request, ActionResponse response)
throws PortletException, java.io.IOException {
if( request.getParameter(FORM_SUBMIT) != null ) {
// Set form text in the session bean
OrdersPortletSessionBean sessionBean = getSessionBean(request);
if( sessionBean != null )
sessionBean.setFormText(request.getParameter(FORM_TEXT));
}
//Initialize the fields in the class as per your requirement
java.lang.String sampleObject = new java.lang.String();
response.setEvent("OrderIDType", sampleObject);
} |
fit your requirement. Because the OrderIDType needs to be sent, the
order ID comes from the action request parameter when the order ID is
selected (see Listing 3).
Listing 3. Code to send the OrderIDType
String order_id = request.getParameter(ORDER_ID);
if (order_id!=null)
response.setEvent("OrderIDType", order_id); |
descriptor, as shown in the Project Explorer in Figure 6. Under the
OrdersPortlet node, the OrderIDType event appears.
Figure 6. Project Explorer
Add the event as a processing event supported by the portlet
Next, the order ID needs to be received by the OrderDetail portlet.
In other words, the event that was published now needs to be processed
by the OrderDetail portlet.
To enable the portlet to process the event:
Expand the Portlet Deployment Descriptor
node.
Right-click the OrderDetail
portlet and select Event > Enable this Portlet to Process Event
.
Figure 7. The process events option
Click to enlarge
The "Enable this portlet to process events" wizard opens, as shown in Figure 8.
Figure 8. Enable this Portlet to Process events window
For the Event Name, select OrderIDType
, which has already
been declared using the event publishing wizard. You cannot modify the
event definition here, but you can edit it manually in the portlet
deployment descriptor.
Click Finish
to complete this processing:
Add the
supported-processing-event
element for the OrderDetail Portlet (you already added the event definition when you published this event)
Modify the
processEvent()
method to process the event
The portlet section for the OrderDetail portlet is modified as Listing 4 shows.
Listing 4. Modifications to the OrderDetail portlet
<portlet> <portlet-name>OrderDetail</portlet-name> <display-name xml:lang="en">OrderDetail</display-name> <display-name>OrderDetail</display-name> <portlet-class> com.ibm.jsr286eventrenderparam.OrderDetailPortlet </portlet-class> <init-param> <name>wps.markup</name> <value>html</value> </init-param> <expiration-cache>0</expiration-cache> <supports> <mime-type>text/html</mime-type> <portlet-mode>view</portlet-mode> </supports> <supported-locale>en</supported-locale> <resource-bundle> com.ibm.jsr286eventrenderparam.nl.OrderDetailPortletResoure </resource-bundle> <portlet-info> <title>OrderDetail</title> <short-title>OrderDetail</short-title> <keywords>OrderDetail</keywords> </portlet-info> <supported-processing-event> <name>OrderIDType</name> </supported-processing-event> </portlet> |
As Listing 5 shows, changes are also made to the
processEvent()
method that is responsible for processing the event that is received.
Listing 5. Modifications to the processEvent( ) method
public void processEvent(EventRequest request, EventResponse response)
throws PortletException, java.io.IOException {
Event sampleEvent = request.getEvent();
if(sampleEvent.getName().toString().equals("OrderIDType")) {
Object sampleProcessObject = sampleEvent.getValue();
} |
processEvent()
method, as the code in bold in Listing 6 shows.
Listing 6. Modifications to the processEvent( ) method
public void processEvent(EventRequest request, EventResponse response)
throws IOException, PortletException {
Event sampleEvent = request.getEvent();
if(sampleEvent .getName().equals("OrderIDType")) {
Object sampleProcessObject = sampleEvent.getValue();
response.setRenderParameter(ORDER_ID, sampleProcessObject.toString());
//set the order id as a render parameter
OrderDetail od = ShippingDB.getOrderDetail(ev.getValue().toString());
if (od != null) {
request.getPortletSession().setAttribute(ORDER_DETAIL, od);
response.setRenderParameter("TrackingID", od.getTrackingId());
//fetch the tracking id from the order details, and set it as a
render parameter.
}
}
} |
doView()
method to add the code that Listing 7 shows in bold.
Listing 7. Modifications to the doView( ) method
String orderId = (String) request.getParameter(ORDER_ID );//get the order set in the processAction() OrderDetail od = ShippingDB.getOrderDetail(orderId); PortletURL actionURL = ShippingUtils.createSimpleActionURL(ORDER_DETAILS, response); odb.setActionURL(actionURL); if (od != null) odb.setOrderDetail(od); getPortletContext().getRequestDispatcher(getJspFilePath(request, VIEW_JSP)) .include(request, response); |
Add the public render parameters
The next step is to use the public render parameter mechanism to
share the tracking ID between the OrderDetail portlet and the Tracking
portlet:
Open the portlet deployment descriptor for the EventSample project.
Select the Render Params
tab, and then click Add
to create a public render parameter with the default name, NewPublicRenderParam.
Change the Name and Identifier fields to
TrackingID
, as shown in Figure 9.
Figure 9. Render Params tab in the Portlet Deployment Descriptor editor
Click to enlarge
This action adds the section shown in Listing 8 to the portlet application definition of the portlet deployment descriptor.
Listing 8. Code snippet added to the portlet deployment descriptor
<public-render-parameter> <identifier>TrackingID</identifier> <name>TrackingID</name> </public-render-parameter> |
OrderDetail portlets, you need to add it as a supported public render
parameter for each of those portlets.
From the Portlets tab, select the Tracking
portlet.
Scroll down to the Supported Public Render Parameters section in the right pane, and click Select
.
For the name, select Tracking ID
, which was created in the Render Params tab in the editor, as shown in Figure 10.
Click OK
.
Repeat Steps 4 and 5 to add
TrackingID
as a supported public render parameter for the OrdersPortlet.
Figure 10 shows the public render parameter added to the portlets.
Figure 10. Supported public render parameter added
Click to enlarge
The changes shown in bold in Listing 9 are made to the portlet deployment descriptor.
Listing 9. Modifications to the portlet deployment descriptor
<portlet> <portlet-name>OrdersPortlet</portlet-name> <display-name xml:lang="en">OrdersPortlet</display-name> <display-name>OrdersPortlet</display-name> <portlet-class> com.ibm.jsr286eventrenderparam.OrdersPortlet </portlet-class> <init-param> <name>wps.markup</name> <value>html</value> </init-param> <expiration-cache>0</expiration-cache> <supports> <mime-type>text/html</mime-type> <portlet-mode>view</portlet-mode> </supports> <supported-locale>en</supported-locale> <resource-bundle> com.ibm.jsr286eventrenderparam.nl.OrdersPortletResource </resource-bundle> <portlet-info> <title>OrdersPortlet</title> <short-title>OrdersPortlet</short-title> <keywords>OrdersPortlet</keywords> </portlet-info> <supported-publishing-event> <name>OrderIDType</name> </supported-publishing-event> <supported-public-render-parameter> TrackingID </supported-public-render-parameter> </portlet> <portlet> <portlet-name>TrackingPortlet</portlet-name> <display-name xml:lang="en">TrackingPortlet</display-name> <display-name>TrackingPortlet</display-name> <portlet-class> com.ibm.jsr286eventrenderparam.TrackingPortlet </portlet-class> <init-param> <name>wps.markup</name> <value>html</value> </init-param> <expiration-cache>0</expiration-cache> <supports> <mime-type>text/html</mime-type> <portlet-mode>view</portlet-mode> </supports> <supported-locale>en</supported-locale> <resource-bundle> com.ibm.jsr286eventrenderparam.nl.TrackingPortletResource </resource-bundle> <portlet-info> <title>TrackingPortlet</title> <short-title>TrackingPortlet</short-title> <keywords>TrackingPortlet</keywords> </portlet-info> <supported-public-render-parameter>TrackingID </supported-public-render-parameter> </portlet> |
doView()
method of the Tracking portlet to display the tracking details, based on the TrackingIDof the order (see Listing 10).
Listing 10. Modifications for the doView( ) method
String renderParam = request.getParameter("TrackingID");
//fetch the tracking id render param which was set in the OrderDetails Portlet
TrackingDetailBean tdb = new TrackingDetailBean();
request.setAttribute(TRACKING_DETAIL_BEAN, tdb);
if (renderParam!=null && renderParam.length()>0) {
PortletURL actionURL =
ShippingUtils.createSimpleActionURL(TRACKING_DETAILS, response);
tdb.setActionURL(actionURL);
PortletURL rdActionURL =
ShippingUtils.createSimpleActionURL(ROUTING_DETAILS, response);
tdb.setRoutingDetailActionURL(rdActionURL);
TrackingDetail td = ShippingDB.getTrackingDetail(renderParam);
if (td != null) {
tdb.setTrackingDetail(td);
getPortletContext().getRequestDispatcher(getJspFilePath
(request, VIEW_JSP)).include(request, response);
} else {
//Tracking id not found; print error page
tdb.setErrorMessage("Tracking Id " + renderParam + " not found.");
getPortletContext().getRequestDispatcher(getJspFilePath
(request, ERROR_JSP)).include(request, response);
}
} |
Publish the portlet project
Now you can publish the portlet application on WebSphere Application Server V6.1:
Right-click the portlet project (see Figure 11) and select Run As > Run on Server
.
Figure 11. Publish the portlet project
Click to enlarge
Select the WebSphere Portal V6.1 Server
, as in Figure 12.
Click Next
, and then click Finish
.
Figure 12. Select the server where you want to run your portlet application
Back to top
Wire the portlets together
The wiring tool that is available on the portal server can help you
wire the relationships between portlets that share events between them.
To access the wiring tool:
Select Edit Page Layout
for the page on which the portlets are placed.
Select the Wires
tab.
For the source portlet, select OrdersPortle
t from the drop-down menu, and for the target portlet, select the OrderDetail
portlet (Figure 13). For the event names, click the drop-down arrow for the Sending
and Receiving
fields.
Figure 13. Add wires to define the relationships in the portlet application
Click to enlarge
Click the plus sign and then click Done
.
Select an order ID (for example, the first one in the OrdersPortlet).
When you click the order ID, an event is triggered by the Orders
portlet, which sends the Order_ID value to the Order Details portlet.
When that portlet receives the order ID, the Order Details Portlet
processes the event. It fetches the details of the order ID and
displays them for the user. In addition, the Order Details portlet
retrieves the tracking ID for the order and communicates the ID to the
tracking details portlet, because the TrackingIDhas been added as a
shared render parameter for both the Order Details and Tracking
portlets. Thus, once the user clicks on an order ID, the order details
and the tracking details are shown to the user (see Figure 14).
Figure 14. The Orders portlet
The user can now see the order and tracking details, as Figure 15
shows. Thus, events and public render parameters are used to transfer
the OrderID and the TrackingIDto the respective portlets.
Figure 15. Order and Tracking detail portlets
Click to enlarge
As you have seen here, the tools provided by Rational Application
Developer 7.5 greatly simplify the creation of events and public render
parameters. You need to customize only the code that is generated to
fit the requirements of your application.
Back to top
Download
| Description | Name | Size | Download method |
|---|---|---|---|
| How to create events and public render parameters | JSR286EventRenderParam.zip | 63KB | HTTP |
Resources
Learn
Learn What's new in the Java Service Specification V2.0 JSR 286) for portlets
.
Read What's new in IBM WebSphere Portal V6.1: JSR 286 features
to learn how the concepts of the new standards, particularly
interportlet communication, have been integrated and get guidelines for
choosing between using portlet events or public render parameters for
communication.
Find out more about public render parameters
, which enable JSR 286 portlets to share navigational state information.
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for technical resources and best practices for Rational Software Delivery Platform products.
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