Portlet Development II
Portlet Actions and Services
Jason Novotny novotny@aei.mpg.de
Michael Russell russell@aei.mpg.de
Oliver Wehrens wehrens@aei.mpg.de
Albert Einstein Institute
HelloWorld continued
HelloWorld example just shows portlet presentation
How to handle actions?
Action handling is performed by
actionPerformed(ActionEvent event) portlet method
To make the example more interesting, allow the
user to click a button which will display a
personalized message
Involves two steps:
Create a JSP page used to render presentation
Augment existing HelloWorld portlet with actionPerformed
method
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
HelloWorld Portlet
Modify the HelloWorld portlet doView method to
create an action and include a JSP page:
package examples.portlets;
public class ActionHelloWorld extends AbstractPortlet {
public void doView(PortletRequest request, PortletResponse response)
throws PortletException, IOException {
PortletURI uri = response.createURI();
uri.addAction("hello_action");
request.setAttribute("action", uri.toString());
getPortletConfig().getContext().include("/jsp/helloworld/actionhello.jsp",
request, response);
}
}
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
HelloWorld JSP
Create webapp/jsp/hello.jsp to display a welcome
message and a form:
<jsp:useBean id="action" class="java.lang.String" scope="request"/>
<jsp:useBean id="name" class="java.lang.String" scope="request"/>
Welcome, <b><%= name %>!</b>
<form method="POST" action="<%= action %>">
<table>
<tr>
<td>Enter your name:</td>
<td><input type="text" name="name" size="20" maxlength="20"/></td>
</tr>
</table>
</form>
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
HelloWorld Portlet
Add the actionPerformed implementation which sets
the name in the request to be rendered by hello.jsp
package examples.portlets;
public class HelloWorld extends AbstractPortlet {
public void actionPerformed(ActionEvent event) {
PortletRequest req = event.getPortletRequest();
String actionName = event.getAction().getName();
if (actionName.equals(“hello_action”)) {
String name = req.getParameter(“name”);
req.setAttribute(“name”, name);
}
}
…
}
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
Portlet Actions
Actions are created either in forms or in links
Actions are created using the PortletURI to construct
an identifier to refer to the calling portlet
Actions are defined by an action name e.g.
‘hello_action’ and may contain additional parameters.
PortletURI offers method “addParameter(String name, String
value)” to associate name value pairs with an action
Action information is obtained from ActionEvent in the
actionPerformed method of a portlet
GridSphere UI tag library makes creation and use of
tags easier (in next tutorial)
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
Check the new portlet!
Re-deploy tutorial webapp
“cd projects/tutorial; ant deploy”
Restart servlet container
‘cd $CATALINA_HOME; bin/startup’
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
Portlet Services
Purpose is to encapsulate business or logic operations that can
be reused across portlets
Minimize logic placed in portlet and make it available as a
reusable library
Services are created and destroyed by a PortletServiceFactory
PortletServices provide init and destroy lifecycle methods
“User services” provide method level access control based on
a User’s access control information
Service tests can be developed and executed using Junit and
Cactus frameworks
Services are defined by a portlet services descriptor
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
Portlet Service Example
Create HelloWorld service that keeps track of
supplied user names.
need to create an interface, implementation and
descriptor of the service
Create src/services/examples/HelloService.java with
two service methods:
public interface HelloService extends PortletService {
public void addName(String name);
public List getNames();
}
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
Portlet Service Example
Create HelloWorld service implementation in
src/services/examples/impl/HelloServiceImpl.java:
public class HelloServiceImpl implements PortletServiceProvider,
HelloService {
private List list = new ArrayList();
public void init(PortletServiceConfig config) { }
public void destroy() { } // for now don’t use
public void addName(String name) {
list.add(name);
}
public List getNames() {
return list;
}
}
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
Portlet Service Example
Add service descriptor entry to webapps/WEBINF/PortletServices.xml:
<service>
<name>HelloService</name>
<description>an example service</description>
<interface>services.examples.HelloService</interface>
<implementation>services.examples.impl.HelloServiceImpl</implementation>
</service>
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
Use Portlet Service
The HelloService may now be used from a portlet
A service instance is obtained via PortletContext
public class HelloWorld extends AbstractPortlet {
public void init(PortletConfig config) throws UnavailableException {
hello = (HelloService)config.getContext().getService(HelloService.class);
}
public void actionPerformed(ActionEvent event) {
PortletRequest req = event.getPortletRequest();
String actionName = event.getAction().getName();
if (actionName.equals(“hello_action”)) {
String name = req.getParameter(“name”);
hello.addName(name);
}
}
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
Portlet User Services
A “User service” provides method level access control
Development approach is to create a service
implementation like before, but should be a singleton:
public class HelloServiceImpl implements PortletServiceProvider,
HelloService {
private HelloWorldServiceImpl instance =
new HelloWorldServiceImpl();
private HelloServiceImpl() {}
public static HelloWorldServiceImpl getInstance() {
return instance;
}
}
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
Portlet User Services
Create a decorator service class that handles method level
authorization:
Constructor must take PortletServiceAuthorizer as parameter
public class HelloUserServiceImpl implements PortletServiceProvider,
HelloService {
private PortletServiceAuthorizer auth = null;
private HelloServiceImpl hello = HelloServiceImpl.getInstance();
public HelloUserServiceImpl(PortletServiceAuthorizer auth) {
this.auth = auth;
}
public List getNames() {
auth.authorizeSuperUser();
return hello.getNames();
}
}
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
Portlet User Services
Modify service descriptor entry in webapps/WEBINF/PortletServices.xml:
User services must set “user-required” attribute true
<service>
<name>HelloService</name>
<user-required>true</user-required>
<description>an example service</description>
<interface>services.examples.HelloService</interface>
<implementation>services.examples.impl.HelloUserServiceImpl
</implementation>
</service>
Portals & Portlets 2003; July 14 -17 2003; Edinburgh
Use Portlet User Service
A user service instance is obtained via PortletContext
as before, but requires User to be supplied
public class HelloWorld extends AbstractPortlet {
public void actionPerformed(ActionEvent event) {
PortletRequest req = event.getPortletRequest();
User user = req.getUser();
// get a hello service instance appropriate for this type of user
hello =
(HelloService)config.getContext().getService(HelloService.class,user);
// will only work for super user
List names = hello.getNames();
}
}
Portals & Portlets 2003; July 14 -17 2003; Edinburgh