Complex classes like Scheduled_Backup often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Scheduled_Backup, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 13 | class Scheduled_Backup { | 
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| 14 | |||
| 15 | /**  | 
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| 16 | * The unique schedule id  | 
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| 17 | *  | 
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| 18 | * @var string  | 
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| 19 | * @access private  | 
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| 20 | */  | 
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| 21 | private $id = '';  | 
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| 22 | |||
| 23 | /**  | 
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| 24 | * The slugified version of the schedule name  | 
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| 25 | *  | 
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| 26 | * @var string  | 
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| 27 | * @access private  | 
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| 28 | */  | 
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| 29 | private $slug = '';  | 
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| 30 | |||
| 31 | /**  | 
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| 32 | * The raw schedule options from the database  | 
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| 33 | *  | 
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| 34 | * @var array  | 
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| 35 | * @access private  | 
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| 36 | */  | 
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| 37 | private $options = array(  | 
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| 38 | 'max_backups' => 3,  | 
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| 39 | 'excludes' => array(),  | 
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| 40 | 'type' => 'complete',  | 
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| 41 | 'reoccurrence' => 'manually'  | 
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| 42 | );  | 
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| 43 | |||
| 44 | /**  | 
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| 45 | * Setup the schedule object  | 
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| 46 | * Loads the options from the database and populates properties  | 
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| 47 | *  | 
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| 48 | * @param string $id  | 
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| 49 | *  | 
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| 50 | * @throws Exception  | 
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| 51 | */  | 
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| 52 | |||
| 53 | 	public function __construct( $id ) { | 
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| 95 | |||
| 96 | /**  | 
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| 97 | * Get the id for this schedule  | 
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| 98 | */  | 
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| 99 | 	public function get_id() { | 
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| 102 | |||
| 103 | /**  | 
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| 104 | * Get a slugified version of name  | 
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| 105 | */  | 
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| 106 | 	public function get_slug() { | 
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| 116 | |||
| 117 | /**  | 
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| 118 | * Returns the given option value  | 
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| 119 | *  | 
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| 120 | * @param $option_name  | 
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| 121 | * @return mixed The option value  | 
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| 122 | */  | 
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| 123 | 	public function get_schedule_option( $option_name ) { | 
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| 128 | |||
| 129 | /**  | 
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| 130 | * Get the name of this backup schedule  | 
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| 131 | *  | 
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| 132 | * @return string  | 
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| 133 | */  | 
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| 134 | 	public function get_name() { | 
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| 137 | |||
| 138 | /**  | 
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| 139 | * Get the type of backup  | 
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| 140 | *  | 
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| 141 | * @return string  | 
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| 142 | */  | 
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| 143 | 	public function get_type() { | 
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| 146 | |||
| 147 | /**  | 
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| 148 | * Set the type of backup  | 
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| 149 | *  | 
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| 150 | * @param string $type  | 
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| 151 | */  | 
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| 152 | 	public function set_type( $type ) { | 
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| 157 | |||
| 158 | /**  | 
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| 159 | * Get the exclude rules  | 
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| 160 | *  | 
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| 161 | * @return array  | 
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| 162 | */  | 
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| 163 | 	public function get_excludes() { | 
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| 166 | |||
| 167 | /**  | 
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| 168 | * Set the exclude rules  | 
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| 169 | *  | 
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| 170 | * @param mixed $excludes A comma separated list or array of exclude rules  | 
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| 171 | * @param bool $append Whether to replace or append to existing rules  | 
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| 172 | *  | 
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| 173 | * @return string  | 
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| 174 | */  | 
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| 175 | 	public function set_excludes( $exclude_rules, $append = false ) { | 
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| 187 | |||
| 188 | /**  | 
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| 189 | * Get the maximum number of backups to keep  | 
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| 190 | *  | 
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| 191 | * @return int  | 
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| 192 | */  | 
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| 193 | 	public function get_max_backups() { | 
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| 196 | |||
| 197 | /**  | 
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| 198 | * Set the maximum number of backups to keep  | 
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| 199 | *  | 
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| 200 | * @param int $max  | 
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| 201 | *  | 
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| 202 | * @return WP_Error|boolean  | 
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| 203 | */  | 
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| 204 | 	public function set_max_backups( $max ) { | 
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| 207 | |||
| 208 | 	public function get_status() { | 
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| 211 | |||
| 212 | /**  | 
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| 213 | * Get the array of services options for this schedule  | 
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| 214 | *  | 
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| 215 | * @param $service  | 
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| 216 | * @param null $option  | 
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| 217 | *  | 
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| 218 | * @return array  | 
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| 219 | */  | 
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| 220 | 	public function get_service_options( $service, $option = null ) { | 
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| 239 | |||
| 240 | /**  | 
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| 241 | * Set the service options for this schedule  | 
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| 242 | *  | 
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| 243 | * @param $service  | 
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| 244 | * @param array $options  | 
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| 245 | */  | 
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| 246 | 	public function set_service_options( $service, Array $options ) { | 
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| 249 | |||
| 250 | /**  | 
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| 251 | * Get the start time for the schedule  | 
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| 252 | *  | 
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| 253 | * @return int timestamp || 0 for manual only schedules  | 
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| 254 | */  | 
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| 255 | 	public function get_schedule_start_time( $gmt = true ) { | 
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| 276 | |||
| 277 | /**  | 
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| 278 | * Set the schedule start time.  | 
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| 279 | *  | 
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| 280 | * @param timestamp $time  | 
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| 281 | */  | 
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| 282 | 	public function set_schedule_start_time( $time ) { | 
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| 289 | |||
| 290 | /**  | 
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| 291 | * Get the schedule reoccurrence  | 
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| 292 | *  | 
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| 293 | */  | 
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| 294 | 	public function get_reoccurrence() { | 
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| 297 | |||
| 298 | /**  | 
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| 299 | * Set the schedule reoccurrence  | 
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| 300 | *  | 
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| 301 | * @param string $reoccurrence  | 
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| 302 | *  | 
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| 303 | * @return \WP_Error|null|boolean  | 
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| 304 | */  | 
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| 305 | 	public function set_reoccurrence( $reoccurrence ) { | 
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| 332 | |||
| 333 | /**  | 
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| 334 | * Get the interval between backups  | 
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| 335 | *  | 
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| 336 | * @return int  | 
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| 337 | */  | 
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| 338 | 	public function get_interval() { | 
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| 349 | |||
| 350 | /**  | 
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| 351 | * Get the next occurrence of this scheduled backup  | 
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| 352 | *  | 
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| 353 | */  | 
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| 354 | 	public function get_next_occurrence( $gmt = true ) { | 
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| 369 | |||
| 370 | 	public function is_cron_scheduled() { | 
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| 373 | |||
| 374 | /**  | 
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| 375 | * Schedule the backup cron  | 
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| 376 | *  | 
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| 377 | */  | 
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| 378 | 	public function schedule() { | 
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| 388 | |||
| 389 | |||
| 390 | /**  | 
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| 391 | * Unschedule the backup cron.  | 
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| 392 | *  | 
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| 393 | * @return void  | 
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| 394 | */  | 
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| 395 | 	public function unschedule() { | 
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| 398 | |||
| 399 | /**  | 
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| 400 | * Run the backup  | 
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| 401 | *  | 
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| 402 | */  | 
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| 403 | 	public function run() { | 
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| 446 | |||
| 447 | 	public function get_backup_filename() { | 
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| 455 | |||
| 456 | 	public function get_database_dump_filename() { | 
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| 459 | |||
| 460 | /**  | 
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| 461 | * Hook into the actions fired in the Backup class and set the status  | 
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| 462 | *  | 
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| 463 | * @param $action  | 
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| 464 | */  | 
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| 465 | 	public function do_action( $action, Site_Backup $backup ) { | 
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| 477 | |||
| 478 | /**  | 
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| 479 | * Calculate schedule run time.  | 
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| 480 | *  | 
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| 481 | * @param int Timestamp $end  | 
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| 482 | */  | 
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| 483 | 	public function update_average_schedule_run_time( $start, $end ) { | 
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| 506 | |||
| 507 | /**  | 
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| 508 | * Calculates the average run time for this schedule.  | 
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| 509 | *  | 
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| 510 | * @return string  | 
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| 511 | */  | 
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| 512 | 	public function get_schedule_average_duration() { | 
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| 550 | |||
| 551 | /**  | 
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| 552 | * Get the backups created by this schedule  | 
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| 553 | *  | 
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| 554 | * @todo look into using recursiveDirectoryIterator and recursiveRegexIterator  | 
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| 555 | * @return string[] - file paths of the backups  | 
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| 556 | */  | 
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| 557 | 	public function get_backups() { | 
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| 580 | |||
| 581 | /**  | 
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| 582 | * Delete old backups  | 
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| 583 | *  | 
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| 584 | * @access private  | 
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| 585 | */  | 
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| 586 | 	public function delete_old_backups() { | 
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| 595 | |||
| 596 | /**  | 
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| 597 | * Delete a specific back up file created by this schedule  | 
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| 598 | *  | 
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| 599 | * @param string $filepath  | 
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| 600 | *  | 
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| 601 | * @return \WP_Error|boolean  | 
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| 602 | */  | 
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| 603 | 	public function delete_backup( $filepath ) { | 
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| 625 | |||
| 626 | /**  | 
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| 627 | * Delete all back up files created by this schedule  | 
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| 628 | *  | 
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| 629 | */  | 
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| 630 | 	public function delete_backups() { | 
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| 633 | |||
| 634 | /**  | 
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| 635 | * Save the schedules options.  | 
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| 636 | *  | 
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| 637 | */  | 
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| 638 | 	public function save() { | 
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| 646 | |||
| 647 | /**  | 
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| 648 | * Cancel this schedule  | 
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| 649 | *  | 
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| 650 | * Cancels the cron job, removes the schedules options  | 
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| 651 | * and optionally deletes all backups created by  | 
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| 652 | * this schedule.  | 
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| 653 | *  | 
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| 654 | */  | 
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| 655 | 	public function cancel( $delete_backups = false ) { | 
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| 669 | |||
| 670 | }  | 
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| 671 | 
It seems like the type of the argument is not accepted by the function/method which you are calling.
In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug.
We suggest to add an explicit type cast like in the following example: