Создание форм/Работа с абстр. классом JModelForm - Общие вопросы по расширениям Joomla

class UsersModelProfile extends JModelForm
{
   ...
}

<?xml version="1.0" encoding="utf-8"?>
	<!-- $Id: profile.xml 20763 2011-02-18 04:50:49Z dextercowley $ -->
<form>
	<fieldset name="core"
		label="COM_USERS_PROFILE_DEFAULT_LABEL">

		<field name="id" type="hidden"
			filter="integer"
		/>

		<field name="name" type="text"
			description="COM_USERS_PROFILE_NAME_DESC"
			filter="string"
			label="COM_USERS_PROFILE_NAME_LABEL"
			message="COM_USERS_PROFILE_NAME_MESSAGE"
			required="false"
			size="30"
		/>

		<field name="username" type="text"
			class="validate-username"
			description="COM_USERS_DESIRED_USERNAME"
			filter="username"
			label="COM_USERS_PROFILE_USERNAME_LABEL"
			message="COM_USERS_PROFILE_USERNAME_MESSAGE"
			required="true"
			size="30"
			validate="username"
			readonly="true"
		/>
     ...
 

<field name="password1" type="password"
			autocomplete="off"
			class="validate-password"
			description="COM_USERS_DESIRED_PASSWORD"
			field="password2"
			filter="raw"
			label="COM_USERS_PROFILE_PASSWORD1_LABEL"
			message="COM_USERS_PROFILE_PASSWORD1_MESSAGE"
			size="30"
			validate="equals"
		/>

class JFormField<Type> extends JFormField
{
	...
}

class JFormRule<NameRule> extends JFormRule
{
	//Переопределить абстрактный метод
        //Возвращает true при успешной валидации, false - во всех остальных
	public function test(& $element, $value, $group = null, & $input = null, & $form = null)
	{
		....
	}
}