Sunday, September 06, 2015

Book Review: Murach's Java Servlets and JSP

Cyndi Vasquez sent me this title a while back. I have been so bogged down that I finally got a chance to look at it. Thanks Murach... this is a good book.

The book is written in a style that many will either love, or hate. I personally am on the former. The pages on the left side are an explanation of the technical matter, and the right side are examples. The book is designed to guide you from front to back on an adventure into programming. Along the safari, I assure you will be pleased. The quarry is knowledge and this book is the tool to capture it.

The books is divided into five sections which will take you from absolute beginner to accomplished Servlet and JSP aficionado. It will even teach you a little about databases, and JSF along the way. There are two appendices that will show you how to set up your computer either Mac, or PC before you get started on your journey.

One of the thrills about this book is the use of NetBeans. I believe that NetBeans is the easiest tool for developing web based applications using Servlets and JSP. It also is my preferred tool for Java development in general. The book not only teaches you about the essentials of the title technologies, but helps you gain an in-depth knowledge of a valuable IDE that you can bank your career on.

Section one covers the basics of the technology and the MVC pattern. This is followed by a crash course on HTML, CSS, and web technologies based on Java.  The 8th chapter on EL is a great reference for how to use this important technology in your web applications.

Section three covers essential database skills to get you started with web development. These skills are the bare minimum to get started, but are complete for the purpose of this book. Keep in mind, these are the basics.

Section four is the meat of the book. This covers the advanced Servlet and JSP skills. It also covers some additional technologies like JSF. My favorite parts of this section are chapters 18, 19, and 20. The HTTP Request and Response skills are something every developer should strive to make sure they understand. Chapter 19 covers listeners which are truly your friends. Chapter 20 covers another often misused, abused, and otherwise fantastic technology. The filter can make your life as a web developer a great pleasure, or a rabbit hole in which you feel like Alice in Wonderland.

The final concluding section five puts all of the pieces together in a Music Store website. The Music Store website uses most of the technologies covered, and takes the learner to the next level with clear and concise directions.

Overall this is a great book for anyone interested in learning about Servlet and JSP technology. Please keep in mind that all Java web technologies are based on the Servlet foundation. JSF is nothing more than a veneer on top of this technology as an example.

Wednesday, April 01, 2015

JSF 2.2 Tip of the Day: p:passthrough and How to use it

I was asking my team to go through their JSF pages, and to update the XML namespaces to use the latest namespace from the JSF 2.2 specification. While I was looking at the code, I found a number of instances where developers were adding attributes like name to <h:commandButton /> and NetBeans correctly was identifying that there is an issue with that.

Fortunately, some of these attributes were passing through to the underlying page without needing p:passthrough. However, you should not rely on such functionality to work. If the VDL Document does not show it as an attribute, you shouldn't expect it to work.

Alright, so how do we do it correctly?

There is no magic here. It is simply a matter of adding the attribute with a prefix of p:, for example p:name="someName" for the name attribute. This will result in the attribute being passed through the rendered and added to the resulting output.

So I have an example, and the resulting output.

The resulting output will run the JavaScript associated with the passed through attributes, or set the CSS styling. Very simple and easy to implement.

Monday, March 30, 2015

Customizing Blogger


I want to start by blaming Markus Eisele for my misadventures. I was looking at his blog and liked the makeover he gave it. I did find the template he was using, but decided that I would write my own. Well I thought this should be an easy thing to do. I severely underestimated the challenge of making a custom template for myself. It turns out that one of the easiest things turns out to be the hardest. Alright Markus you are off the hook... it may just be my bravado, and belief I can build a better mousetrap that led me down the long lonesome road.

Google is well known for having good and sometimes great APIs for their technology. Blogger is an exception to that rule. There is not one clear cut schema for their layout that I can find ironically using Google itself. You figure with all of the templates and bloggers that this would be covered ad nauseum.  It is not though.


I was looking for a simple and elegant framework to make my blog sites look professional, and also make them portable. I had the following requirements:
  1. Mature framework
  2. Can be found on a CDN
  3. Easy to use
  4. Simple to implement
  5. Well Documented
  6. Lots of examples
  7. Flexible
  8. Customizable
  9. Response UI
  10. HTML5
  11. Portable
  12. JSF Compatible
  13. Works with NetBeans IDE for Tooling
I looked at a number of frameworks including Foundation, and Bootstrap. I ended up choosing Foundation since it seemed to be easier to use for me. Your milage my vary.

The first thing I wanted to know was what was the minimum required for a template on Blogger. I discovered that are a couple of versions of the template: an HTML 4.01 version (v.1) and an HTML 5 version (v.2) which are somewhat a hybrid mix of XML, and (X)HTML. I published the basic templates on Gist as shown below.

I have a couple of different blogs and found them to be different so I thought I would share my findings.

The next thing I needed to find out was what was the minimal template I would need for using with Foundation. The template below uses a CDN to deliver the required JS/CSS. The template below is the culmination of a lot of work to make it work with the visual tools on Blogger. Remember to backup your existing template before installing mine.


I finally have a working blog site using the new template, and will update all of my sites to use it. My personal non-technical blog site was the first to use the new template. It is still a work in progress, but it looks very nice. Take a peek for yourself at John Yeary Blogger site.

I have compiled a list of links that I found helpful in trying to figure out their layouts and tags in the references below.



Template References

Additional References

Friday, March 27, 2015

A Simple Method to invoke @PreDestroy on a Class

I was experimenting with how to invoke a @PreDestroy annotated method in a class. This will approach will work with other annotations as well.

Tuesday, February 17, 2015

JSF 2.x Tip of the Day: Implementing a ViewMapListener

A map of the lands where the Trobadors flourished. 
"France 1154-en" by Reigen - Own work
Licensed under CC BY-SA 4.0 via Wikimedia Commons.


There are a number of SystemEvents supported by JSF 2.x. A question that comes up frequently is how to implement them. In a number of cases on stackoverflow, it is implemented using a PhaseListener. I was looking for a way to cleanup the view map, or just get values from it before it was destroyed. I decided that the simplest way to do so was to implement a ViewMapListener. I also noticed that there were very few posts on how to implement it using the faces-config.xml so I decided to use that approach since it was instructive and more clear to me.


The basic implementation requires that you add our listener implementation to the faces-config.xml. The example I have here is designed to get called on a PreDestroyViewMapEvent which is called on a normal navigation. We can force it though by adding a @PreDestroy annotation to a method to invoke before being destroyed. Inside the method we would need to get the UIViewroot view map, and call clear(). This would cause our listener to be invoked too. It would be a good cleanup mechanism for cleaning up resources on session expiration too, but at the moment this does not work on JSF 2.1. The @PreDestroy is not called on session timeout on JSF 2.1. This is expected to be an enhancement in JSF 2.2+.

The code for the project can be downloaded from Bitbuket here: viewmaplistener-example


The example above is just one mechanism of using a SystemEvent listener. You may decide to read values from the map, and add them to the session, or manipulate it in some other way before the data is destroyed.

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