class ProfileValues

class ProfileValues extends Migration {
    
    /**
     * Flag determining whether the process plugin has been initialized.
     *
     * @var bool
     */
    protected $init = FALSE;
    
    /**
     * {@inheritdoc}
     */
    public function getProcess() {
        if (!$this->init) {
            $this->init = TRUE;
            $definition['source'] = [
                'plugin' => 'profile_field',
                'ignore_map' => TRUE,
            ] + $this->source;
            $definition['destination']['plugin'] = 'null';
            $definition['idMap']['plugin'] = 'null';
            try {
                $this->checkRequirements();
                $profile_field_migration = $this->migrationPluginManager
                    ->createStubMigration($definition);
                $migrate_executable = new MigrateExecutable($profile_field_migration);
                $source_plugin = $profile_field_migration->getSourcePlugin();
                $source_plugin->checkRequirements();
                foreach ($source_plugin as $row) {
                    $name = $row->getSourceProperty('name');
                    $fid = $row->getSourceProperty('fid');
                    // The user profile field name can be greater than 32 characters. Use
                    // the migrated profile field name in the process pipeline.
                    $configuration = [
                        'migration' => 'user_profile_field',
                        'source_ids' => $fid,
                        'no_stub' => TRUE,
                    ];
                    $plugin = $this->processPluginManager
                        ->createInstance('migration_lookup', $configuration, $profile_field_migration);
                    $new_value = $plugin->transform($fid, $migrate_executable, $row, 'tmp');
                    if (isset($new_value[1])) {
                        // Set the destination to the migrated profile field name.
                        $this->process[$new_value[1]] = $name;
                    }
                }
            } catch (RequirementsException) {
                // The checkRequirements() call will fail when the profile module does
                // not exist on the source site, or if the required migrations have not
                // yet run.
            }
        }
        return parent::getProcess();
    }

}