<?php

namespace Drupal\Core\Field\Plugin\Field\FieldType;

use Drupal\Core\Field\FieldItemBase;
use Drupal\Core\Field\FieldStorageDefinitionInterface;
use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\Core\TypedData\DataDefinition;

/**
 * Base class for string field types.
 */
abstract class StringItemBase extends FieldItemBase {

  /**
   * {@inheritdoc}
   */
  public static function defaultStorageSettings() {
    return [
      'case_sensitive' => FALSE,
    ] + parent::defaultStorageSettings();
  }

  /**
   * {@inheritdoc}
   */
  public static function propertyDefinitions(FieldStorageDefinitionInterface $field_definition) {
    // This is called very early by the user entity roles field. Prevent
    // early t() calls by using the TranslatableMarkup.
    $properties['value'] = DataDefinition::create('string')
      ->setLabel(new TranslatableMarkup('Text value'))
      ->setSetting('case_sensitive', $field_definition->getSetting('case_sensitive'))
      ->setRequired(TRUE);

    return $properties;
  }

  /**
   * {@inheritdoc}
   */
  public function isEmpty() {
    $value = $this->get('value')->getValue();
    return $value === NULL || $value === '';
  }

}