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Category Archives: Design Pattern

If you love IBM Domino – please learn Java, NOW!

It’s now over 3 years ago that I head to take over a project, which covers a critical business case. And it was one of my most painful experience ever. It ends up that each day I worked on that project, I took pain-killer. The request was quite simple: “Please rollback a Java agent to a LotusScript Agent”. But I’ve never seen such a painful implementation of Java. It was quite horrible and against all that I’ve learned about Java.

But Java is the most important language for the future of IBM Domino. If you’re an Application Developer please learn Java. And please learn it, like you would learn something new. Trow away all your knowledge about programing, you can reintroduce it later. Here my advises how you should start:

  1. Download Eclipse
  2. Read Head First Java
  3. Do all examples from HeadFirst Java
  4. Read Design Patterns from HeadFirst
  5. Read Effective Java from Joshua Bloch

“I have not the time for that” could be your answer. The most of us do not have the time for our own education, but only 30 minute per day will pay of in a short time. And reading this books has also a positive effect on coding with Lotus Script ūüôā

“How do I bring that in my Domino / Notes Projects?” – This is one of the most critical part. But in fact it’s very easy. DECIDE and DO….

…. and there is webinar this Thursday January 16 from TLCC and Teamstudio which covers XPages and Java Development. I hope you will participate: http://www.tlcc.com/admin/tlccsite.nsf/pages/xpages-webinar

And when you feel your self fit with Java, it’s time for the best-selling developer book form IBM Press called Mastering XPages.

 

 

 
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Posted by on January 12, 2014 in Design Pattern, Domino, Java, XPages

 

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Paid per line programming code? – Why I love refactoring

Earlier this month I’ve started to read a new book called “Effective Java“. Jesse Gallagher mentioned this book as a “must read”. After my positive journey with reading “Design Pattern” (The head first edition) was it no question that I definitely read the sample of “Effective Java”. And yes, after reading the sample, I bought it. (To my colleges at WebGate: Yes be afraid – I have now a new book – Ho Ho Ho).

But reading a book without bring the new knowledge into the daily work is only the half of fun. So where to start? One of the first thing that has attracted me while reading “Effective Java” was the initialization of a Singleton.

A Singleton is an object, which exist only one time in specific context like a jvm, plugin or a XPages Application. The “normal” code to initialize a singleton is the following construct:

public class DocumentProcessor {
private static DocumentProcessor m_Processor;
private DocumentProcessor() {
}

public static DocumentProcessor getInstance() {
if (m_Processor == null) {
m_Processor = new DocumentProcessor();
}
return m_Processor;
}
}

One of the disadvantage of this code is, that this code is not “safe” if you try to create an instance of DocumentProcessor with Java Reflection and modifying the constructor. The other thing that I’m not loving is the amount of code, that I always have to write. But Joshua Bloch explains a simple way with enums to have a singleton look at this code:

public enum DocumentProcessor {
INSTANCE;
}

How smart is this! And not much code. I’m not paid per line of code I write, so it’s not touching my income :). Now you can access with DocumentProcessor.INSTANCE the singleton. It’s very cool, but what, if I have already a lots of Singleton? How can I make that my code will not break the code of other clients (classes which calls my API).

Remember all client classes call the current code (before refactoring) with WordProcessor.getInstance(). I can easy change this in my classes, but external clients which calls my WordProcessor will fail, when the do not have the WordProcessor.getInstance().

The following code is a “defensive” approach which makes this safe to all the other clients:

public enum DocumentProcessor {
INSTANCE;

/**
* gets the Instance of the DocumentProcessor.
*
* @deprecated -> Use DocumentProcessor.INSTANCE instead
*
* @return Instance of the DocumentProcessor
*/
@Deprecated
public static DocumentProcessor getInstance() {
return DocumentProcessor.INSTANCE;
}

This code is not only safe, it gives the other developer also an instruction, how to adapt the new API.

Will I now go to all my code (and it’s a lot of code I wrote each year) and change this all? And what about all the other cools stuff that I will learn while reading the book?

No, that’s not my approach. But I will challenge my code, myself and later the WebGate Development Team with the knowledge. Each code that I’ve to touch will also be reviewed with my new knowledge.

Have fun

Christian

 
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Posted by on December 21, 2013 in Design Pattern, Domino, Java, XPages

 

Ready for todays webinar about OpenNTF Essentials?

I hope that you have already dowloaded OpenNTF Essentials and at least installed on your development computer. If not, it’s a 5 minute job as you can see in this youtube video http://youtu.be/EUrLfJcCQhY (starting 12:00).

In Todays webinar, Mark will cover some cool stuff about debugging and Nathan takes a deep dive into the OpenNTF Domino API. My part will be about some cool @nnotations. Imagine this:

Your are writing a call center application and you have designed the “Call” object as a java object according the java bean specification. With the ObjectData Source from the ExtLib are you know ready to edit each field of this java object, but now you have to save…..¬†and read …. and delete ….. the object from the database.

I will show you in todays webinar how you can do this with writing only “3 or 4” lines of code ūüôā

I hope you will join us, today 10:30 EST, register now!

 
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Posted by on December 12, 2013 in Architektur, Design Pattern, Domino, Java, OpenNTF, XPT

 

The “ninja-style” programming model by WebGate

First I’ve to excuse that we are so selfish to call our programming model ninja-style. It was happened based on the fact, that we have programmed ninjas in internal programming course. But the term ninja-style was established and if you gave something a name, it’s very hard to change it (Maybe you have seen Monster.Inc by Pixar, then you know what I mean).

Our intention is to make programming for XPages as much fun as possible.  And fun means in the case of programming: Having success, with less of effort and stress.

But the ninja-style has also to do with leaving the comfort zone and go out from this protected workshop in which the most of the domino developers where living. XPages requires a complete new set of skills. On the front end part are you faced with: HTML5, JavaScript, CSS, DOJO (and that’s only the beginning) and of course SSJS for the binding part. On the backend is Java the most required skills, that you should have. But you have also to learn about data sources, controls, data binding and something called JSF life-cycle.

Definitely a lot of topics to cover and the most of us are not geniuses, specially universal genius. It’s a matter of fact that it is easier to split and separate the topics. Because of this we have introduced the N-Tier architecture to our programming model. We have separated the front end stuff, from the back-end stuff.

The front end covers all the presentation (Presentation Layer)

Typically our front end developers are brilliant in arranging all the controls in the XPages and they are mostly virtuous in JavaScript, CSS and Dojo. They know about the “beans” as far as they have to know how to use them as API to the model and the business logic. They don’t care, how object are loaded and stored, they don’t care about how processes and logic are executed, as long all is working correct.

The backend covers all the model and business logic (Business logic Layer)

The back-end guys do all the brilliant stuff with the model of the data and all the processes. Mostly they are Java Cracks or on the way to it. They care about good backend performance and have read the book “design pattern” by the gang of for. No interface and connection to any backend is to complex for them, but do not let them do any HTML stuff.

But where are the storage guys?

At this point, some of the core features of the XPT cames to action. The DSS of the XPT solves all the storage stuff.

But keep this: Having success with XPages has to be about simplification. Our first step was to separate front end from back-end.

To be continued >>>

Christian

 

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How open source protects your work – a short story.

Hello my readers

during the next days I’m preparing the 8th edition of Kids and Teeniedays in Effretikon. So many of my blogs will cover my social engagement. But this one is related to two different stories in my it-life, that now merges.

The first story began in the 90s. My former employer gave me the chance to learn all things about lotus notes and domino. During our work, we decided to change our development model to object orientated lotus script. One of my first work was a “FormBase” class. This class could handle a simple validation. based on empty fields. After a while, this class was a part of every application in this company. External consultants joined the company, and after a while I found this class in commercial products, in other companies.

As you could imagine, I was disappointed and a bit angry for several reasons. First, I missed my name on the source code. Later I was afraid, if anyone could know that this code was one of my first object orientated work in lotus script. Because it was not so brilliant. After reading design pattern, a great book, i was shocked, which fundamental mistake I did make. But this is another story. But how to handle, that your brilliant work is not copied? And is reinventing the wheel also coping?

There are other typical problems that you are facing, by preventing your code. But there is a very interesting other way to protect your work. Make it openSource. Put it under a openSource license, like Apache or GPL, and go to public. So anybody can see your work and give the credits to your work. An example?

The notesUI of myWebGate

The notesUI of myWebGate

Im really proud of the NotesUI of myWebGate. Even if nobody sees this. Richie Schmid did a brilliant user interface which is in many of our applications and loved by our customers. . Richie has made it several years before we even think about setting this under the terms of the Apache V2 license.

But I think this nice UI has the power to be a quasi standard like the oneUI of IBM. And I was a little bit surprised how fast we see the first adaption. Take a look at this link

So how to implement our UI in your application? Its very simple. You have to give credits to the myWebGate project, as we did with the silk icons we used (and several other brilliant open source work).

Go ahead, make brilliant software, use our UI, but give honor to the right people.

 
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Posted by on August 6, 2012 in Design Pattern, myWebGate

 

Accessing Beans from Java Code in XPages (learned by Reading the SourceCode of the ExtensionLibrary)

Hello Java and XPages Fans

During our work for the myWebGate 2.0 OpenNTF Edition i was faced with a very simple Problem. I had to access a public method in one of our managed beans. This managed beans are designed to act as session facade. So the bean name is directory bean and the scope is session. The ClassName is based on our internal guidlines DirectorySessionFasade.

In this class, is a method called getMySelf() witch gives me some information about my current user in context of the myWebGate Framework. The powerfull thing about managed beans is, that the object exists only one time baed on the scope, in this case one time each session.

For our activtystream implementation I have to acces this getMySelf() methode, because all my relations are stored in the returning object. A short google search doesnt help, but I rember that I’ve ready a pattern in the ExtensionLibrary, that maby can help. An voilaz there it was, written by Phillip Riand, I found some thing that I changed to this for my situation:

public static final String BEAN_NAME = “directoryBean”; //$NON-NLS-1$
    
public static DirectorySessionFacade get(FacesContext context) {
        DirectorySessionFacade bean = (DirectorySessionFacade)context.getApplication().getVariableResolver().resolveVariable(context, BEAN_NAME);
        return bean;
    }
    
    public static DirectorySessionFacade get() {
        return get(FacesContext.getCurrentInstance());
    }

This simple codesnipped gives you the capability to execute DirectorySessionFacade.get().getMySelf(). The DirectorySessionFacade.get() Code calls the get( FacesContext context() and there the inmemory Variable directoryBean can be accessed.

What a simple construct to access the same instance in java as in the SSJS and XPAGES. Thanks to IBM for sharing the ExtensionLibrary as OpenSource.