return array_keys($vars);
}
+ /**
+ * {@inheritdoc}
+ */
+ public function isInternal() {
+ // Respect the definition, otherwise default to TRUE for computed fields.
+ if (isset($this->definition['internal'])) {
+ return $this->definition['internal'];
+ }
+ return $this->isComputed();
+ }
+
+ /**
+ * Sets the whether the data value should be internal.
+ *
+ * @param bool $internal
+ * Whether the data value should be internal.
+ *
+ * @return $this
+ */
+ public function setInternal($internal) {
+ $this->definition['internal'] = $internal;
+ return $this;
+ }
+
}