Custom post type registration class.

class-custom-post-type.php

<?php
/**
 * Custom Post Type Registration.
 *
 * @package   Contract Builder
 * @author    ThemeAvenue <contact@themeavenue.net>
 * @license   GPL-2.0+
 * @link      http://themeavenue.net
 * @copyright 2013 ThemeAvenue
 */

/**
 * Register custom post types
 *
 * @package Contract Builder
 * @author  Julien Liabeuf <julien@liabeuf.fr>
 * @version 1.0.0
 */
if( !class_exists( 'TAV_Custom_Post_Type' ) ) {
	
	class TAV_Custom_Post_Type {

		/**
		 * Instance of this class.
		 *
		 * @since    1.0.0
		 *
		 * @var      object
		 */
		protected static $instance = null;

		public function __construct( $name = false, $id = null, $args = array(), $labels = array() ) {

			/**
			 * A name for the custom post type is the minimum required.
			 * If no name is defined, we can't proceed with the registration.
			 */
			if( $name && null != $id ) {

				$this->cpt_name 	   = sanitize_text_field( $name );
				$this->cpt_name_plural = $this->cpt_name . 's';
				$this->cpt_slug 	   = $id;
				$this->labels 		   = $labels;
				$this->args 		   = $args;

				if( !post_type_exists( $this->cpt_slug ) ) {

					add_action( 'init', array( $this, 'register_post_type' ), 15 );

				}

			}

		}

		/**
		 * Return an instance of this class.
		 *
		 * @since     1.0.0
		 *
		 * @return    object    A single instance of this class.
		 */
		public static function get_instance() {

			// If the single instance hasn't been set, set it now.
			if ( null == self::$instance ) {
				self::$instance = new self;
			}

			return self::$instance;
		}

		/**
		 * Get the post type labels
		 *
		 * @since 1.0.0
		 * @return (array) Post type labels
		 */
		public function get_labels() {

			$singular = $this->cpt_name;
			$plural   = $this->cpt_name_plural;

			/* Set the default labels */

			/**
			 * @todo Translation doesn't work well. Find a good way to have everything translated
			 */
			$labels = array(
				'name'                  => $plural, 'post type general name',  
				'singular_name'         => $singular,  
				'add_new'               => __( 'Add New', strtolower( $singular ) ),  
				'add_new_item'          => __( 'Add New ' . $singular ),  
				'edit_item'             => __( 'Edit ' . $singular ),  
				'new_item'              => __( 'New ' . $singular ),  
				'all_items'             => __( 'All ' . $plural ),  
				'view_item'             => __( 'View ' . $singular ),  
				'search_items'          => __( 'Search ' . $plural ),  
				'not_found'             => __( 'No ' . strtolower( $singular ) . ' found'),  
				'not_found_in_trash'    => __( 'No ' . strtolower( $plural ) . ' found in Trash'),   
				'parent_item_colon'     => '',  
				'menu_name'             => $plural
			);

			return array_merge( $labels, $this->labels );

		}

		/**
		 * Get post type arguments
		 *
		 * @since 1.0.0
		 * @return (array) Post type arguments
		 */
		public function get_arguments() {

			$args = array(
				'labels'             => $this->get_labels(),
				'public'             => true,
				'publicly_queryable' => true,
				'show_ui'            => true,
				'show_in_menu'       => true,
				'query_var'          => true,
				'capability_type'    => 'post',
				'has_archive'        => true,
				'hierarchical'       => false,
				'menu_position'      => null,
				'supports'           => array( 'title', 'editor' )
			);

			return array_merge( $args, $this->args );

		}

		/**
		 * Register the new post type
		 *
		 * @since 1.0.0
		 */
		public function register_post_type() {

			register_post_type( $this->cpt_slug, $this->get_arguments() );

		}

	}
}