silverstripe /
silverstripe-framework
Complex classes like ManyManyList 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 ManyManyList, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 9 | class ManyManyList extends RelationList { |
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| 10 | |||
| 11 | /** |
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| 12 | * @var string $joinTable |
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| 13 | */ |
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| 14 | protected $joinTable; |
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| 15 | |||
| 16 | /** |
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| 17 | * @var string $localKey |
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| 18 | */ |
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| 19 | protected $localKey; |
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| 20 | |||
| 21 | /** |
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| 22 | * @var string $foreignKey |
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| 23 | */ |
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| 24 | protected $foreignKey; |
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| 25 | |||
| 26 | /** |
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| 27 | * @var array $extraFields |
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| 28 | */ |
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| 29 | protected $extraFields; |
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| 30 | |||
| 31 | /** |
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| 32 | * @var array $_compositeExtraFields |
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| 33 | */ |
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| 34 | protected $_compositeExtraFields = array(); |
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| 35 | |||
| 36 | /** |
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| 37 | * Create a new ManyManyList object. |
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| 38 | * |
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| 39 | * A ManyManyList object represents a list of {@link DataObject} records |
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| 40 | * that correspond to a many-many relationship. |
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| 41 | * |
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| 42 | * Generation of the appropriate record set is left up to the caller, using |
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| 43 | * the normal {@link DataList} methods. Addition arguments are used to |
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| 44 | * support {@@link add()} and {@link remove()} methods. |
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| 45 | * |
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| 46 | * @param string $dataClass The class of the DataObjects that this will list. |
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| 47 | * @param string $joinTable The name of the table whose entries define the content of this many_many relation. |
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| 48 | * @param string $localKey The key in the join table that maps to the dataClass' PK. |
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| 49 | * @param string $foreignKey The key in the join table that maps to joined class' PK. |
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| 50 | * @param array $extraFields A map of field => fieldtype of extra fields on the join table. |
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| 51 | * |
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| 52 | * @example new ManyManyList('Group','Group_Members', 'GroupID', 'MemberID'); |
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| 53 | */ |
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| 54 | public function __construct($dataClass, $joinTable, $localKey, $foreignKey, $extraFields = array()) { |
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| 64 | |||
| 65 | /** |
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| 66 | * Setup the join between this dataobject and the necessary mapping table |
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| 67 | */ |
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| 68 | protected function linkJoinTable() { |
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| 78 | |||
| 79 | /** |
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| 80 | * Adds the many_many_extraFields to the select of the underlying |
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| 81 | * {@link DataQuery}. |
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| 82 | * |
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| 83 | * @return void |
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| 84 | */ |
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| 85 | protected function appendExtraFieldsToQuery() { |
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| 109 | |||
| 110 | /** |
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| 111 | * Create a DataObject from the given SQL row. |
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| 112 | * |
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| 113 | * @param array $row |
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| 114 | * @return DataObject |
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| 115 | */ |
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| 116 | protected function createDataObject($row) { |
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| 149 | |||
| 150 | /** |
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| 151 | * Return a filter expression for when getting the contents of the |
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| 152 | * relationship for some foreign ID |
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| 153 | * |
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| 154 | * @param int|null $id |
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| 155 | * |
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| 156 | * @return array |
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| 157 | */ |
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| 158 | protected function foreignIDFilter($id = null) { |
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| 171 | |||
| 172 | /** |
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| 173 | * Return a filter expression for the join table when writing to the join table |
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| 174 | * |
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| 175 | * When writing (add, remove, removeByID), we need to filter the join table to just the relevant |
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| 176 | * entries. However some subclasses of ManyManyList (Member_GroupSet) modify foreignIDFilter to |
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| 177 | * include additional calculated entries, so we need different filters when reading and when writing |
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| 178 | * |
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| 179 | * @param array|int|null $id (optional) An ID or an array of IDs - if not provided, will use the current ids |
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| 180 | * as per getForeignID |
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| 181 | * @return array Condition In array(SQL => parameters format) |
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| 182 | */ |
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| 183 | protected function foreignIDWriteFilter($id = null) { |
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| 186 | |||
| 187 | /** |
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| 188 | * Add an item to this many_many relationship |
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| 189 | * Does so by adding an entry to the joinTable. |
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| 190 | * |
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| 191 | * Can also be used to update an already existing joinTable entry |
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| 192 | * |
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| 193 | * Example: |
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| 194 | * |
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| 195 | * $manyManyList->add($recordID, array("ExtraField"=>"value")); |
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| 196 | * |
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| 197 | * |
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| 198 | * @throws InvalidArgumentException |
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| 199 | * @throws Exception |
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| 200 | * |
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| 201 | * @param DataObject|int $item |
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| 202 | * @param array $extraFields A map of additional columns to insert into the joinTable. |
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| 203 | * Column names should be ANSI quoted. |
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| 204 | */ |
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| 205 | public function add($item, $extraFields = array()) { |
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| 291 | |||
| 292 | /** |
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| 293 | * Remove the given item from this list. |
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| 294 | * |
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| 295 | * Note that for a ManyManyList, the item is never actually deleted, only |
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| 296 | * the join table is affected. |
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| 297 | * |
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| 298 | * @param DataObject $item |
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| 299 | */ |
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| 300 | public function remove($item) { |
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| 307 | |||
| 308 | /** |
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| 309 | * Remove the given item from this list. |
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| 310 | * |
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| 311 | * Note that for a ManyManyList, the item is never actually deleted, only |
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| 312 | * the join table is affected |
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| 313 | * |
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| 314 | * @param int $itemID The item ID |
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| 315 | */ |
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| 316 | public function removeByID($itemID) { |
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| 330 | |||
| 331 | /** |
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| 332 | * Remove all items from this many-many join. To remove a subset of items, |
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| 333 | * filter it first. |
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| 334 | * |
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| 335 | * @return void |
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| 336 | */ |
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| 337 | public function removeAll() { |
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| 365 | |||
| 366 | /** |
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| 367 | * Find the extra field data for a single row of the relationship join |
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| 368 | * table, given the known child ID. |
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| 369 | * |
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| 370 | * @param string $componentName The name of the component |
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| 371 | * @param int $itemID The ID of the child for the relationship |
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| 372 | * |
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| 373 | * @return array Map of fieldName => fieldValue |
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| 374 | */ |
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| 375 | public function getExtraData($componentName, $itemID) { |
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| 410 | |||
| 411 | /** |
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| 412 | * Gets the join table used for the relationship. |
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| 413 | * |
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| 414 | * @return string the name of the table |
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| 415 | */ |
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| 416 | public function getJoinTable() { |
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| 419 | |||
| 420 | /** |
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| 421 | * Gets the key used to store the ID of the local/parent object. |
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| 422 | * |
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| 423 | * @return string the field name |
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| 424 | */ |
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| 425 | public function getLocalKey() { |
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| 428 | |||
| 429 | /** |
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| 430 | * Gets the key used to store the ID of the foreign/child object. |
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| 431 | * |
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| 432 | * @return string the field name |
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| 433 | */ |
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| 434 | public function getForeignKey() { |
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| 437 | |||
| 438 | /** |
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| 439 | * Gets the extra fields included in the relationship. |
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| 440 | * |
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| 441 | * @return array a map of field names to types |
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| 442 | */ |
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| 443 | public function getExtraFields() { |
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| 446 | |||
| 447 | } |
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| 448 |
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This check marks implicit conversions of arrays to boolean values in a comparison. While in PHP an empty array is considered to be equal (but not identical) to false, this is not always apparent.
Consider making the comparison explicit by using
empty(..)or! empty(...)instead.