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Revision as of 21:38, 18 April 2009

Unit Configs
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Unit Configuration File Registration of Unit Classes Defining Database, Virtual and Calculated Fields Formatters Hooks Regular Events Using "TitlePresets" Option

To use a particular class in K4, it must first be registered. Class registration is a process, the result of which is that K4 learns:

• The name of the class;
• The location of the file where the class is written;
• The pseudo that's going to be used when referring to an object of the class.

pseudo - a keyword that can be used from any place in K4 to get an object of a class that's registered under the pseudo.

Getting an Object

The kApplication::recallObject can be used to get an object, for example:

$price =& $this->Application->recallObject('price');
/* @var $price kDBItem */

In order for auto-complete to work in Zend Studio, it's necessary to put a specially formatted comment after getting an object. The general form of this kind of comment is:

/* @var $variable_name ClassName */

Registering a Class

In a configuration file there are a number of options with similar formats for the purpose of registering classes in K4:

In the above table, "<prefix>" is the value of the Prefix option in a configuration file. The value of each above option (except RegisterClasses) is an array of the following format:

Array (
	'class' => 'ClassName',
	'file' => 'FileName',
	'build_event' => 'BuildEventName',
	'require_classes' => 'RequiredClassName'
)

All of the keys in this array, except require_classes, are required. However, the value of some of the keys can be empty.

The value of all keys (except build_event) of this array must follow naming conventions rules]].

Substituting Classes

There are cases when one or more classes used in the system must be substituted. To do this, the RegisterClasses key is used. When registering or substituting a class, in the RegisterClasses key it's required to indicate an additional pseudo key. In this case it must be set because it's not known automatically (like in all of the previously described situations).

'RegisterClasses' => Array (
	Array ('pseudo' => 'u_TagProcessor', 'class' => 'EUserTagProcessor', 'file' => 'e_user_tp.php'), // substitute a user tag processor
	Array ('pseudo' => 'PermissionsHelper', 'class' => 'ЕPermissionsHelper', 'file' => 'e_permission_helper.php'), // substitute a class helper
)

• When substituting a class the "pseudo" must be set with which the original (i.e. the one being substituted) class was registered.
• Registration of the substitute class must be done after registration of the original class. This requirement is automatically fulfilled if class substitution is done in the "custom/units/sections_config.php" file.

Standard Classes

The following standard classes are available:

• kDBItem - class for working with one database record;
• kDBList - class for displaying the contents of a database table (filters, per-page, etc.);
• kDBEventHandler - class for processing standard events from lists and edit forms;
• kDBTagProcessor - class for processing standard tags used for displaying information;
• kEventHandler - root class for all event handlers (use only with the goal of reducing memory usage);

The value of the file key should be empty for standard classes.