Design Pattern in PHP: Iterator Pattern

Whilst working on my AOP framework for PHP, I needed a versatile iterator. Here is what I came up with:

Javascript for PHP developers: Part I: Static Class

Here is how I would code a static class in Javascript by borrowing from my PHP experience:

Javascript

PHP

<br />// Function declaration<br />// Serves as "static class" declaration<br />// Will be attached to the 'window' object<br />// by default.<br />JLD = function() {<br /> // Static variable<br /> // Only accessible within 'JLD' <br /> var var1 = 666;<br />}<br /> <br />// Static Function declaration<br />// under the "static class" JLD<br />// Typeof JLD.fnc1 = "function"<br />JLD.fnc1 = function() {<br /><br /> // can't access var1 inside function JLD<br /> alert( "JLD.fnc1 called. var1= " + JLD.var1 );<br />}<br /><br />// 'fields' of JLD<br />JLD.var2 = 777; //typeof JLD.var2 = "number"<br />JLD.var3 = "some string"; //typeof JLD.var3 = "string"<br /><br />// Static Function declaration<br />// under the "class" JLD<br />JLD.fnc2 = function() {<br /> <br /> // can access var2 though<br /> alert( "JLD.fnc2 called. var2= " + JLD.var2 );<br />}<br /><br />

<br /> class JLD {<br /> <br /> function JLD() {<br /> var $var1 = 666;<br /> }<br /><br /> function fnc1() {<br /> // of course can't access $var1<br /> }<br /><br /> static $var2 = 777;<br /> static $var3 = "some string";<br /><br /> function fnc2() {<br /> // can access $var2 & $var3<br /> echo self::$var2;<br /> echo self::$var3;<br /> }<br />}<br />

Design Pattern in PHP: Factory pattern

The factory pattern is most interesting when Testing and Refactoring because one can substitute a class implementation for another without changing the core code.

In the example below, I have demonstrated a versatile factory method which sports object instance creation with a variable parameter list.

• Base::factory( $className /*optional parameters*/ ) creates an object of class $className with, optionally, a list of parameters passed to the constructor
• E.g. $object = Base::factory( 'TestClass', 'param1', 'param2' );
• Base::mapClass( $sourceClassName, $targetClassName ) adds a mapping entry so that the factory builds an object instance of $targetClassName instead of $sourceClassName when asked to build for $sourceClassName
• E.g. Base::mapClass( 'TestClass', 'TestDebugClass' );
  

Project
The project is located at GoogleCode.

Design Pattern in PHP: Template Method

This next design pattern should not be mistaken with the common template conception (see Web template) more commonly found in web-technologies.

The template method pattern is designed with a base class which contains an high-level recipe and relies on sub-classes to specify the ingredients. An example would be a template for publishing a table of objects: the template method base class would implement the publishing logic whilst the sub-class would extract the relevant data pieces to expose in the table.

Project
The project is located at GoogleCode.

Using Yahoo! Pipes with WEB-Services

I recently struggled a bit with Yahoo! Pipes when playing with this great tool trying to form a properly updating RSS feed from a WEB-Service source. The WEB-Service in question is available through one of Ohloh's API : Project.

The issue was related to the <guid> field required by (most?) RSS Aggregators (I use the excellent GoogleReader): fetching a data feed from a WEB-Service API usually means that no "proper" feed is in place and an RSS item must be created on-the-fly. This is no problem as such but when the RSS aggregator comes fetching updates, the <guid> field isn't updated dynamically by Yahoo! Pipes.

Part of the solution comes from using a mostly undocumented feature of Pipes: the y:id.value item tag.

After fetching the data from the data source, copy a field that can serve as good <guid> into the y:id.value field. In the example above, I used the updated_at field which, of course, isn't a <guid> per-se by not being global ; I'll find a better way next time around.


Finally, before connecting the "pipe output", insert the y:id.value in the pipes results as shown above.

For the interested, here is the pipe's address: Ohloh Project Summary as well as a link to all my pipes.

Have fun with Pipes... I know I do!