intrduced spec interface and created support method

module/VuFind/src/VuFind/RecordDataFormatter/Specs/AbstractBase.php

@@ -45,7 +45,7 @@
  * @link     https://vufind.org/wiki/development:architecture:record_data_formatter
  * Wiki
  */
-abstract class AbstractBase implements \VuFind\I18n\Translator\TranslatorAwareInterface
+abstract class AbstractBase implements SpecInterface, \VuFind\I18n\Translator\TranslatorAwareInterface
 {
     use \VuFind\I18n\Translator\TranslatorAwareTrait;
 

module/VuFind/src/VuFind/RecordDataFormatter/Specs/PluginManager.php

@@ -59,6 +59,6 @@ class PluginManager extends \VuFind\ServiceManager\AbstractPluginManager
      */
     protected function getExpectedInterface()
     {
-        return AbstractBase::class;
+        return SpecInterface::class;
     }
 }

module/VuFind/src/VuFind/RecordDataFormatter/Specs/SpecInterface.php

@@ -0,0 +1,53 @@
+<?php
+
+/**
+ * RecordDataFormatter specs interface.
+ *
+ * PHP version 8
+ *
+ * Copyright (C) Hebis Verbundzentrale 2025.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * @category VuFind
+ * @package  RecordDataFormatter
+ * @author   Thomas Wagener <[email protected]>
+ * @license  http://opensource.org/licenses/gpl-2.0.php GNU General Public License
+ * @link     https://vufind.org/wiki/development:architecture:record_data_formatter
+ * Wiki
+ */
+
+namespace VuFind\RecordDataFormatter\Specs;
+
+/**
+ * RecordDataFormatter specs interface.
+ *
+ * @category VuFind
+ * @package  RecordDataFormatter
+ * @author   Thomas Wagener <[email protected]>
+ * @license  http://opensource.org/licenses/gpl-2.0.php GNU General Public License
+ * @link     https://vufind.org/wiki/development:architecture:record_data_formatter
+ * Wiki
+ */
+interface SpecInterface
+{
+    /**
+     * Get default configuration.
+     *
+     * @param string $key Key for configuration to look up.
+     *
+     * @return array
+     */
+    public function getDefaults(string $key): array;
+}

module/VuFind/src/VuFind/View/Helper/Root/RecordDataFormatter.php

@@ -33,6 +33,7 @@
 
 use Laminas\View\Helper\AbstractHelper;
 use VuFind\RecordDataFormatter\Specs\PluginManager as SpecsManager;
+use VuFind\RecordDataFormatter\Specs\SpecInterface;
 use VuFind\RecordDriver\AbstractBase as RecordDriver;
 
 use function call_user_func;
@@ -215,14 +216,10 @@ public function getData(...$args): array
      */
     public function getDefaults(string $key): array
     {
-        $specClass = \VuFind\RecordDataFormatter\Specs\DefaultRecord::class;
-        if ($this->driver !== null) {
-            $specClass = $this->driver->getRecordDataFormatterSpecClass();
+        $specs = $this->getSpecPluginForDriver();
+        if ($specs === null) {
+            throw new \Exception('Using the RecordDataFormatter view helper with a driver that is not supported.');
         }
-        if ($specClass === null) {
-            return [];
-        }
-        $specs = $this->specsManager->get($specClass);
         return $specs->getDefaults($key);
     }
 
@@ -238,16 +235,28 @@ public function getDefaults(string $key): array
      * @deprecated Set defaults on spec class directly
      */
     public function setDefaults(string $key, array|callable $values): void
+    {
+        $specs = $this->getSpecPluginForDriver();
+        if ($specs !== null && method_exists($specs, 'setDefaults')) {
+            $specs->setDefaults($key, $values);
+        }
+    }
+
+    /**
+     * Get matching spec plugin for the driver.
+     *
+     * @return ?SpecInterface
+     */
+    protected function getSpecPluginForDriver(): ?SpecInterface
     {
         $specClass = \VuFind\RecordDataFormatter\Specs\DefaultRecord::class;
         if ($this->driver !== null) {
             $specClass = $this->driver->getRecordDataFormatterSpecClass();
         }
         if ($specClass === null) {
-            return;
+            return null;
         }
-        $specs = $this->specsManager->get($specClass);
-        $specs->setDefaults($key, $values);
+        return $this->specsManager->get($specClass);
     }
 
     /**