In this post we will be looking at code for a system designed to integrate all of the devices used to provide surveillance and security to extensive physical premises such as malls, campuses, and industrial parks. The approach I am taking involves the actor paradigm and the Java programming language. The selection of actors for this type of application is based on a number of...
on Nov 30, 2013
I just finished delivering a talk at Oredev 2013 on better concurrency in Java 8. With Lambda’s being the biggest new feature I naturally needed to address what they had to offer. I wanted a meatier example than the ones where you write a query to find all the people that make more than you do so I decided to write the example around was on how to sum up all the application stopped time records...
on Nov 10, 2013
Each of these objects can be described in terms of the classes or types to which they belong for instance a maple tree belongs to the class of tree or is a type of tree, a bicycle is a type of cycle, a car is a type of vehicle. OOP is thus a very powerful language abstraction that allows you to simplify the complexity of a problem while retaining its value. Java is an Object Oriented...
on Oct 16, 2013
Exciting information technologies emerge from new discoveries and re-emerge from past discoveries at a rapid rate. Despite the glamor and curiosity appeal engendered by cutting edge technologies when they debut, after the hype fades and we look at what actually is there in the cold light of reason we find ourselves turning to our pragmatic side and asking:
“Ok, but what advantages do we...
on Oct 15, 2013
In Java development, the typical data computation problems are characterized with:
Long computation procedure requiring a great deal of debugging
Data may from database, or Excel/Txt
Data may from multiple databases, instead of just one.
Some computation goals are complex, such as relative position computation, and set-related computation
Just suppose a sales department needs to make statistics...
on Aug 13, 2013
Java API for WebSocket is a new JSR to Java EE 7. It provides a stardard Java API for creating WebSocket applications. This gives web applications the ability to push data.
In Java EE 6 samples, we added a chat room sample to illustrate how to use of Servlet 3.0 asynchronous operation. In that sample, the servlet code did the following:
keep track of AsyncContext in a Queue
create a thread to...
on Aug 13, 2013
Our books are great. But don’t just trust us; here are some reviews from developers who have actually bought, read and loved the books. Trust them!
Clojure Made Simple – John Stevenson
Great first step into Clojure, a pleasure to read – Sisu **** 4 Stars
I’m new to Clojure, and rather than coming to grips immediately with functional programming for large projects, I wanted to get familiar with...
on Jul 29, 2013
In Java development, we may encounter the complex set operations. Java alone is not powerful enough to save programmers’ efforts in implementing the computation details, which is time-consuming and poor in code reuse. In view of this, programmers usually resort to dynamic calculation script for set operation.
SQL is surely the first kind of script that comes into most programmers’ mind. However,...
on Jul 16, 2013
How much code documentation is a symptom of bad coding (i.e. poor method or variables names, poor class or package structure, missing logging, etc)?
on Jul 15, 2013
This post introduces a new Java actor based open source sub-project of the project "Learning Actors in Java". This work will develop a premises guardian system. A premises guardian system is a distributed application whose purpose is to support the physical protection of premises such as office buildings, campuses, apartment complexes, shopping malls, etc. Protecting information...
on Nov 20, 2013
Remote systems cannot be ignored. They are the heart of actor programming. The ability of an actor application to smoothly scale out geographically is a tremendous advantage in meeting the challenges of growth. Today we will learn the basics of setting up for remote interaction between actors. If you wish to set up to try coding a set of remote actor systems and do not as yet have a...
on Nov 10, 2013
Configuration of an actor system affects the way in which the Akka actor libraries and microkernel interact with actors. The visibility of a configuration is limited to the specific actor system with which the configuration has been associated. The effective configuration for any given actor system is a merger of three sources. In Fig. 1 below the precedence of...
on Oct 30, 2013
This week I am presenting a coding of a simple two actor application designed to show actor creation, message passing, and actor termination. This application is called the "Fortune Cookie Application". It is the next state of the art beyond the HelloWorld program. Despite its simplicity this application shows the elements that every actor application uses.
What We Will Be...
on Oct 22, 2013
As I get closer to deploying our 4th Operational Release of the Duke's Choice award winning GEONS Ground System Software I'm combining the NetBeans Platform with custom JavaFX views. This pattern provides some very useful "At-a-Glance" displays associated with daily data product generation. I'm fortunate to have access to quite a bit of complex and timely data much of which is custom to the...
on Nov 10, 2013
What happens if you configure a Hadoop-centric scalable big data infrastructure running on the Amazon EC2 cloud, that's programmed to perform some very basic processing on delimited ASCII data records (about 30 characters in each record), and you feed it a single data record? How quickly do you think that massively powerful system would process that teensy, trivial input data set? Milliseconds?...
on Sep 26, 2013
At the JavaOne 2013 Java Technical Keynote, there was a series of demos of software that enables two people to play chess, using some of Java's latest features, including Java EE 7 Websockets, many variations of Java 8 (recent weekly builds), Lambda Expressions, Java ME, Embedded Java, ... It was an impressive demo of many of Java's recently-released and not-yet-finally-released capabilities,...
on Sep 23, 2013
Recently, I was asked to participate in creating another Java application at my company.
It was to be our team's third major Java application since 2002.
We felt we had plenty of wisdom from our previous two Java applications to apply to our third one.
One of our first steps was to form an application architecture sub-team.
This sub-team's purpose was to provide the development team with a solid...
on Sep 22, 2013
My company uses a large number of software applications to support all aspects of its business.
These software applications are either "bought" or "built".
The portions of the company that cannot be supported by purchased software are
supported by custom developed, in-house, applications.
A variety of technologies are used to create and build these custom applications.
The Java framework has been...
on Sep 15, 2013
A while ago, I was asked to evaluate another Java application that was being used at my company.
It was a point-of-sale app, developed entirely "in-house" by one of our overseas affiliates.
I wondered what their MVC model would look like.
How different would their Java app be from the ones I have worked on?
I started my evaluation by learning all I could about the architecture and design of this...
on Sep 8, 2013
Spring is an open source framework whose goals is facilitate the Java developer's life, it began with dependency injection and nowadays works on many plug-ins. Plug-ins such Spring Social, to connects social media like twitter and facebbok, Spring security beyond control inversion. The goal of this post is talk about Spring Data working with Cassandra.
Spring Data does part of Spring plug-in,...
on Aug 25, 2013