October 28th, 2007 Radim Marek
It’s a long wait for JBoss version 5. If you’re anxious to get more information without digging deep into the beta version or current trunk, there are notes available from Mark Newton’s presentation ‘What’s new’ in JBoss AS 5, published on Christian Bauer’s blog.
Link: JBoss AS 5 Presentation Liveblog
Posted in jboss | No Comments »
October 16th, 2007 Radim Marek
As a die hard fan of IntelliJ IDEA , I’m happy to let you know that the guys from JetBrains released version 7.0 aka The Magnificent Seven.
For more information and list of changes, visit official blog.
Updated: as it isn’t mentioned in original announcement, I’m glad IDEA is finally using runtime of Java 6. After my initial surprise caused by anti-aliased fonts in menus and dialogs, the version information (Help/About) confirmed it.
Posted in Java | 1 Comment »
October 14th, 2007 Radim Marek
An important characteristic of every framework is a level of possible extensibility. JBoss Seam scores top marks in this perspective. Reason for it is simple. The main goal, to introduce consistent programming model that will make various frameworks to work together, is not just promoted for application developer, but also used through-out Seam itself. So with knowledge how to use component model and a quick insight behind the scene, you can easily start extending built-in components.
Mechanism you need to understand is component deployment process. Seam application start-up is triggered by the context listener which instantiates the Initialization object responsible for building configuration metadata. That is accomplished by collection of data from standard configuration files (WEB-INF/components.xml and deprecated WEB-INF/events.xml), configuration properties (supplied both from servlet context and file name seam.properties in the root of the classpath) and eventually by scanning archives in the application classpath for classes annotated with @Name which implies the Seam component.
Dependency Manager is then responsible for evaluation of component dependency to determine which components are to be installed.
And that’s the place where Seam utilizes another annotation - @Install. It does not only specify whether or not the component should be installed (this might be overridden by configuration files) and its dependencies, but also specifies precedence of the component. If two components with the same name are present, Dependency Manager will offer for installation only the one with higher precedence.
The precedence is specified integer value and following pre-defined constants are available:
Further control over the components deployment process is provided by following two annotations:
With this overview you’re ready to extend any provided component, either Seam built-in or available within 3rd party framework or application.
As example I’ll show you how to extend built-in identity object to support custom JAAS Login Module that requires custom callback handler to be used to obtain/provide further information. This particular implementation adds functionality to support NTLM as other authentication method (together with customized jCIFS library) and NTLM support iself is not part of this code snapshot.
@Name(”org.jboss.seam.security.identity”)
@Scope(SESSION)
@Install(precedence = APPLICATION)
@BypassInterceptors
@Startup
public class NTLMIdentity extends Identity {
//
// custom code
//
@Override
public String login() {
try {
retrieveNTLMAuthenticationDetails();
} catch (LoginException le) {
log.error(”Unable to retrieve NTLM authentication details!”, le);
return null;
}
}
@Override
protected CallbackHandler getDefaultCallbackHandler() {
return new CallbackHandler() {
public void handle(Callback[] callbacks)
throws IOException, UnsupportedCallbackException {
for (int i = 0; i < callbacks.length; i++) {
if (callbacks[i] instanceof NameCallback) {
((NameCallback) callbacks[i]).setName(getUsername());
} else if (callbacks[i] instanceof PasswordCallback) {
((PasswordCallback) callbacks[i]).setPassword(getPassword() != null ?
getPassword().toCharArray() : null);
} else if (callbacks[i] instanceof SFSIdentityCallbackHandler) {
processSFSCallbackHandler((SFSIdentityCallbackHandler) callbacks[i]);
} else {
throw new UnsupportedCallbackException(callbacks[i], “Unsupported callback”);
}
}
}
};
}
//
// custom code
//
}
Where @Name is specified to override Seam built-in Identity component, and precedence set higher than BUILT_IN. If you run application, the result of #{identity} and Identity.instance() will always be NTLMIdentity object.
Posted in seam | 4 Comments »
October 6th, 2007 Radim Marek
Next week I will be doing an in-house JBoss Seam training for client who migrates frontend solution from .NET to Java. Because my personal experiments are mainly based on upcoming version 2.0, the fact second release candidate is available and GA release is just few days away, the whole training is built around the new version. For better understanding I’ve compiled description of some features and changes in Seam 2.0 from documentation and JIRA tickets.
Please note that this description is based only on my personal investigation and isn’t provided from project (RedHat/JBoss) sources.
New features are:
Posted in seam | 1 Comment »
October 2nd, 2007 Radim Marek
Since the release as part of Java 5 (formerly called J2SDK 5.0) the Java Management Extensions proved to be effective tool for management of the application systems and intercommunication between the various software components. JBoss AS’ kernel itself relies on JMX as the integration bus into which various components plug.
Although there are many developers successfully using JMX, general knowledge often doesn’t cover more advanced aspects of this technology. This is a first part of my series to shed light on not so common parts of the specification and hopefully help you to take advantage of it and understand some aspects of systems build on top of JMX. First part of this series is dedicated to ability of MBean to broadcast management events to its listeners, called notifications.
Posted in Java | No Comments »
You are currently browsing the laststation.net weblog archives for October, 2007.