Roy's Technology Diary

I recently discovered some little-known ways to use a GMail address that can give you greater control over your inbox and save you some time. Actually, when you choose a Gmail address, you actually get more than just "yourusername@gmail.com"; here are two different ways you can modify your Gmail address and still continue getting your mails: Append a plus ("+") sign and any combination of words or numbers after your email address. For example, if your name was yourusername @gmail.com, you could send mail to yourusername +friends@gmail.com or yourusername +mailinglists@gmail.com. Insert one or several dots (".") anywhere in your email address. Gmail doesn't recognize periods as characters in addresses -- Google mail just ignores them. For example, you could tell people your address was hikingfan@gmail.com, hiking.fan@gmail.com or hi.kin.g.fan@gmail.com. For me, the real value in being able to manipulate your email address is that it makes it really easy...

The Simple XML serialization framework has released version 1.2. Simple is a serialization framework for Java that intends to provide an XML serialization framework that requires no configuration or mappings to serialize objects bi-directionally; i.e. to and from standard XML. Below is a list of some of the capabilities of the framework. Simple framework with powerful capabilities The framework used to provide XML serialization is simple to use and revolves around several annotations an a single persister object used to read and write objects to and from XML. Both serialization and deserialization are fully supported. It requires absolutely no configuration Unlike many of the XML frameworks for Java there are no mappings or configuration required to serialize objects regardless of its complexity, not even code to establish mappings. Everything is done at runtime, only annotations are required to perform the object to XML structure. The XML schema is represented using field and method a...

In many texts String is cited as the ultimate benchmark of Java's various immutable classes. Well, I'm sure you'd have to think the other way once you have read this article. To start with, let's get back to the books and read the definition of immutability. The Wikipedia defines it as follows - 'In object-oriented and functional programming, an immutable object is an object whose state cannot be modified after it is created.' I personally find this definition good as it mentions that an immutable instance's state should not be allowed to be modified after it's construction. Now keeping this in the back of our minds, let's decompile Java's standard String implementation and peep into the hashCode() method - public int hashCode() { int h = hash; if (h == 0) { int off = offset; char val[] = value; int len = count; for (int i = 0; i h = 31*h + val[off++]; } hash = h; } return h; } A detailed ...

Whilst developing web applications, more than often we are confronted with the need to validate user inputs. On the client-side (browsers) we generally do that with scripting languages; and for those users who have perhaps deliberately disabled their browser script support; we perform the same set validation on the server side, and this time we write some lines-of-code to extract the user input from the HTTP request and validate the same. Well, although ironic; yet it seems to be a de-facto that - we have to specify the validation rules separately on the client and server side, for eventually validating something that is semantically same. A technical analysis into the core reason reveals that – although the semantics of the herein discussed "thing" (i.e. the user input) are the same, yet the representations of the semantic on the client and server side are different; which enforces us to implement the extraction and validation logic differently. So going by that theory - if ...

Schematron is a rule-based validation language for making assertions about patterns found in XML documents. It is a simple language which is based very much on XML itself and uses standard XPath to specify the assertion statements. The Schematron definations (a.k.a Schema) can be processed with standard XSL templates; which makes Schematron applicable is a variety of scenarios. Although a Schematron defination is referred as a Schema, but one must understand that Schematron differs in the basic concept from other schema languages; i.e. it is not based on grammars but on finding tree patterns in the parsed document. This approach allows many kinds of structures to be represented which could be difficult with grammar-based schema languages. For instance - imagine how would a typical schema be, for the following XML document - <?xml version="1.0" encoding="UTF-8"?> <instance> #### <person> ######## <fname/> ######## <lname/> #### </pers...

Work in Progress The Scarlet project is currently under development. Please keep an eye on the sourceforge project site (sourceforge.net/projects/scarlets) or contact personally for updates. Introduction to Domain Specific Language (DSL) Domain-specific languages have lately become a hot topic and a lot is being spoken and written about them all over the internet; much of the buzz around functional languages is their applicability to (once again) put the power and control of an application in exactly the right place where it belongs, i.e. in the hands of its users. By defining a simple language that the application users can understand, feel comfortable to communicate and use, programmers can effectively reduce their involvement in the never-ending cycle of UI requests and enhancements and can let users create scripts and other tools that allow them to create newer behavior in the applications they use. A perfect example of a wildly successful DSL is the Microsoft® Office Excel ...

Its been quite a while since my last post here. I understand that my sudden disappearing act must have annoyed a many of my regular visitors; especially the ones who are expecting the second part of the XRX tutorial. Whilst you wait for the concluding part of the XRX article, I thought of sharing somethings that i found to be interesting - As Java Web application frameworks have become more powerful and flexible, they've also become more complex. John O'Hanley's WEB4J framework in many ways flies in the face of this trend: it offers few customization options, but is easy to learn and work with. Read on to learn about the unusual (and somewhat contrarian) development principles behind WEB4J. You'll also have the opportunity to test out the framework by building a feature for a sample Web application... [ more ]