ExampleDevelGenerate.php

<?php

namespace Drupal\devel_generate_example\Plugin\DevelGenerate;

use Drupal\devel_generate\DevelGenerateBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Provides a ExampleDevelGenerate plugin.
 *
 * @DevelGenerate(
 *   id = "devel_generate_example",
 *   label = "Example",
 *   description = "Generate a given number of examples. Optionally delete current examples.",
 *   url = "devel_generate_example",
 *   permission = "administer devel_generate",
 *   settings = {
 *     "num" = 50,
 *     "kill" = FALSE
 *   }
 * )
 */
class ExampleDevelGenerate extends DevelGenerateBase {
    public function settingsForm(array $form, FormStateInterface $form_state) {
        $form['num'] = array(
            '#type' => 'textfield',
            '#title' => $this->t('How many examples would you like to generate?'),
            '#default_value' => $this->getSetting('num'),
            '#size' => 10,
        );
        $form['kill'] = array(
            '#type' => 'checkbox',
            '#title' => $this->t('Delete all examples before generating new examples.'),
            '#default_value' => $this->getSetting('kill'),
        );
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function generateElements(array $values) {
        $num = $values['num'];
        $kill = $values['kill'];
        if ($kill) {
            $this->setMessage($this->t('Old examples have been deleted.'));
        }
        
        //Creating user in order to demonstrate
        // how to override default business login generation.
        $edit = array(
            'uid' => NULL,
            'name' => 'example_devel_generate',
            'pass' => '',
            'mail' => 'example_devel_generate@example.com',
            'status' => 1,
            'created' => REQUEST_TIME,
            'roles' => '',
            'devel_generate' => TRUE,
        );
        $account = user_load_by_name('example_devel_generate');
        if (!$account) {
            $account = entity_create('user', $edit);
        }
        // Populate all fields with sample values.
        $this->populateFields($account);
        $account->save();
        $this->setMessage($this->t('@num_examples created.', array(
            '@num_examples' => $this->formatPlural($num, '1 example', '@count examples'),
        )));
    }
    public function validateDrushParams($args) {
        $values = array(
            'num' => array_shift($args),
            'kill' => drush_get_option('kill'),
        );
        return $values;
    }

}