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PaymentMethods Form Field

PaymentMethodsField is a ListField subclass that queries #__extensions for all enabled plugins in the j2commerce group whose element name begins with payment_. Before each option label is rendered, the plugin's own language file is loaded so that the plugin's name constant (e.g. PLG_J2COMMERCE_PAYMENT_CASH) resolves to the correct translated string without requiring those strings in the component language file.

Key Classes​

ClassFilePurpose
PaymentMethodsFieldadministrator/components/com_j2commerce/src/Field/PaymentMethodsField.phpQueries extensions table; loads plugin language files

Database Query​

SELECT element AS value, name AS text
FROM #__extensions
WHERE type     = 'plugin'
  AND folder   = 'j2commerce'
  AND element  LIKE '%payment_%'
  AND enabled  = 1
ORDER BY name ASC

The element column (e.g. payment_cash) is used as the option value. The name column stores the language constant (e.g. PLG_J2COMMERCE_PAYMENT_CASH), which is translated only after the plugin's language file is loaded.

Per-Plugin Language Loading​

Each plugin's language file is loaded on-the-fly before the option is created:

$lang->load('plg_j2commerce_' . $method->value, JPATH_PLUGINS . '/j2commerce/' . $method->value);

This means:

  • The language file must exist at plugins/j2commerce/element/language/en-GB/plg_j2commerce_element.ini.
  • If the file is absent, the raw language key appears in the dropdown.
  • The standard Joomla language fallback chain applies.

XML Usage​

<!-- File: administrator/components/com_j2commerce/forms/coupon.xml (example) -->

<form addfieldprefix="J2Commerce\Component\J2commerce\Administrator\Field">
    <fieldset name="restrictions">
        <field
            name="payment_method"
            type="PaymentMethods"
            label="COM_J2COMMERCE_FIELD_PAYMENT_METHOD_LABEL"
            description="COM_J2COMMERCE_FIELD_PAYMENT_METHOD_DESC"
        />
    </fieldset>
</form>

XML Attributes​

AttributeTypeDefaultDescription
typestring—Must be PaymentMethods
multipleboolfalseAllow selecting more than one payment method
requiredboolfalseMark field as required
defaultstring—Pre-selected element name, e.g. payment_cash

All standard Joomla ListField attributes apply. Static <option> tags in the XML (e.g. for "Any method") are included before the database-sourced options via parent::getOptions().

Error Handling​

If the database query throws an exception, the error is caught and an admin message is displayed using COM_J2COMMERCE_ERROR_LOADING_PAYMENT_METHODS. The dropdown will contain only the static options defined in XML (if any).

Usage in Plugin Forms​

Use this field in any plugin that needs to restrict its behaviour to a specific payment method:

<!-- File: plugins/j2commerce/app_yourplugin/config.xml -->

<?xml version="1.0" encoding="UTF-8"?>
<config>
    <fields name="params">
        <fieldset name="basic" label="COM_PLUGINS_BASIC_FIELDSET_LABEL">
            <field
                name="allowed_payment_methods"
                type="PaymentMethods"
                addfieldprefix="J2Commerce\Component\J2commerce\Administrator\Field"
                label="PLG_J2COMMERCE_APP_YOURPLUGIN_FIELD_PAYMENT_METHODS_LABEL"
                description="PLG_J2COMMERCE_APP_YOURPLUGIN_FIELD_PAYMENT_METHODS_DESC"
                multiple="true"
            >
                <option value="">PLG_J2COMMERCE_APP_YOURPLUGIN_OPTION_ANY_PAYMENT</option>
            </field>
        </fieldset>
    </fields>
</config>

Naming Convention for Payment Plugin Elements​

Payment plugin element names must match the pattern %payment_% (note the leading %) for the SQL LIKE filter to include them. The conventional format is:

payment_{provider}

Examples: payment_cash, payment_stripe, payment_paypal.

A plugin with element mypayment_custom would not appear in the dropdown because it does not match %payment_%. The element name must contain payment_ as a substring.