--- /dev/null
+<?php
+
+namespace Drupal\image_module_test\Plugin\Field\FieldType;
+
+use Drupal\Core\Field\FieldItemBase;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+use Drupal\Core\TypedData\DataDefinition;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+
+/**
+ * Defines a dummy field containing an AJAX handler.
+ *
+ * @FieldType(
+ * id = "image_module_test_dummy_ajax",
+ * label = @Translation("Dummy AJAX"),
+ * description = @Translation("A field containing an AJAX handler."),
+ * category = @Translation("Field"),
+ * default_widget = "image_module_test_dummy_ajax_widget",
+ * default_formatter = "image_module_test_dummy_ajax_formatter"
+ * )
+ */
+class DummyAjaxItem extends FieldItemBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ public static function schema(FieldStorageDefinitionInterface $field_definition) {
+ return [
+ 'columns' => [
+ 'value' => [
+ 'type' => 'varchar',
+ 'length' => 255,
+ ],
+ ],
+ ];
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function isEmpty() {
+ return empty($this->get('value')->getValue());
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public static function propertyDefinitions(FieldStorageDefinitionInterface $field_definition) {
+ $properties['value'] = DataDefinition::create('string')
+ ->setLabel(new TranslatableMarkup('Dummy string value'));
+
+ return $properties;
+ }
+
+}