I have been using JAX-RS for many REST-based service implementations in Java.
As part of my journey into the Google Go programming language, I am exploring designs for such REST support using the standard net/http package in Go.
JAX-RS provides a set of Annotation classes which can be used to add meta-data to classes, methods and method arguments. In JAX-RS these annotation are used to specify the mapping between a Http Request to a Java method and its arguments.
renderSnake is a open-source library for creating components that produce HTML using only Java. By defining Java classes for HTML components and pages you can exploit all the language features (e.g. inheritance, composition, type-checking) and IDE tooling (e.g. refactoring, unit-testing, references search, debugging,…). In addition, renderSnake is designed to produce compact HTML in an memory efficient way.
@RequestMapping("/productlist.html")
@ResponseBody
public void showProductListPage(HtmlCanvas html) throws IOException {
html.getPageContext().set("products", this.productListDao.getBestSellersProductList());
html.render(new WebshopLayoutWrapper(new ProductListPage())));
}
Class Head is an example UI component responsible for rendering the head section of every HTML page. It implements the Renderable interface and uses the HtmlCanvas parameter object for rendering. The HtmlCanvas object has methods of all elements (tags) in order to write HTML content. Using the HtmlAttributesFactory, you can specify the attributes for each HTML tag. By convention, the method source has a format that uses indentation to see the nesting of tags. This is not required but improves its readability.
Every now and then I need a small piece of functionality that perfectly fits into a single, minimal-behavior thus single-purpose class. This time I am developping a Adobe Flex application that uses the RemoteObject facilities. Before invoking a method on a RemoteObject, you have to add two event handlers that will be called with a ResultEvent or a FaultEvent respectively. Typically in the “onResult(event:ResultEvent)” function, one takes the result of the event and calls another function or update a view.
Too often developers put logic in so-called Helper classes.
This practice of SPOD (Single Point of Definition) results in a higher level of reusability, so it seems. But in fact introducing these procedural structured behavioral methods impose a rigid structure. First of all, (other) developers need to be aware that such Helpers exist to work on their objects. Secondly, because behavior that should have been defined in the class of the object, is now defined elsewhere. The possibility of re-using such behavoir by inheritance is now unavailable. You cannot just extend an Helper class too!
How can I provide programs with self diagnostic behavior? How can I implement this in a way that has low impact on the way I write programs (or Java classes to be more specific). If programs could run such a self diagnose then perhaps it takes less time to find the cause of an observed problem.
These thoughts are sprung when I found an error in an application that went into production just a few days earlier. The problem itself was easily fixed (just a typo in some properties file) but I was a bit surprised that obviously my tests did not cover this particular execution path. Sure, I should have written more tests to have a higher coverage (JCoverage can tell me what percentage), but what if I had programmed this behavior differently(how?) such that a self diagnose run would have detected it?
Another example of how negative publicity can have a big learning effect (if understood). From a new entry @ slashdot about Multi-links, I surfed to WebsitesThatSuck. The authors are committed to show the worst designs that live on the web.
With respect to Software Design, my dialy work, a similar initiative has been around for a few years. In response to the popular Design Patterns book written by the Gang of Four, others introduced the Anti-Patterns as a means to teach designers about the dont’s in the design of systems using Object Technology. You can contribute to them using the Anti-Patterns Wiki.