Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like MSSQLSchemaManager 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 MSSQLSchemaManager, and based on these observations, apply Extract Interface, too.
| 1 | <?php | ||
| 8 | |||
| 9 | |||
| 10 | /** | ||
| 11 | * Represents and handles all schema management for a MS SQL database | ||
| 12 | * | ||
| 13 | * @package mssql | ||
| 14 | */ | ||
| 15 | class MSSQLSchemaManager extends DBSchemaManager | ||
| 16 | { | ||
| 17 | |||
| 18 | /** | ||
| 19 | * Stores per-request cached constraint checks that come from the database. | ||
| 20 | * | ||
| 21 | * @var array | ||
| 22 | */ | ||
| 23 | protected static $cached_checks = array(); | ||
| 24 | |||
| 25 | /** | ||
| 26 | * Builds the internal MS SQL Server index name given the silverstripe table and index name | ||
| 27 | * | ||
| 28 | * @param string $tableName | ||
| 29 | * @param string $indexName | ||
| 30 | * @param string $prefix The optional prefix for the index. Defaults to "ix" for indexes. | ||
| 31 | * @return string The name of the index | ||
| 32 | */ | ||
| 33 | public function buildMSSQLIndexName($tableName, $indexName, $prefix = 'ix') | ||
| 42 | |||
| 43 | |||
| 44 | /** | ||
| 45 | * This will set up the full text search capabilities. | ||
| 46 | * | ||
| 47 | * @param string $name Name of full text catalog to use | ||
| 48 | */ | ||
| 49 | public function createFullTextCatalog($name = 'ftCatalog') | ||
| 56 | |||
| 57 | /** | ||
| 58 | * Check that a fulltext catalog has been created yet. | ||
| 59 | * | ||
| 60 | * @param string $name Name of full text catalog to use | ||
| 61 | * @return boolean | ||
| 62 | */ | ||
| 63 | public function fullTextCatalogExists($name = 'ftCatalog') | ||
| 70 | |||
| 71 | /** | ||
| 72 | * Sleep until the catalog has been fully rebuilt. This is a busy wait designed for situations | ||
| 73 | * when you need to be sure the index is up to date - for example in unit tests. | ||
| 74 | * | ||
| 75 | * TODO: move this to Database class? Can we assume this will be useful for all databases? | ||
| 76 | * Also see the wrapper functions "waitUntilIndexingFinished" in SearchFormTest and TranslatableSearchFormTest | ||
| 77 | * | ||
| 78 | * @param int $maxWaitingTime Time in seconds to wait for the database. | ||
| 79 | */ | ||
| 80 | public function waitUntilIndexingFinished($maxWaitingTime = 15) | ||
| 100 | |||
| 101 | /** | ||
| 102 | * Check if a fulltext index exists on a particular table name. | ||
| 103 | * | ||
| 104 | * @param string $tableName | ||
| 105 | * @return boolean TRUE index exists | FALSE index does not exist | NULL no support | ||
| 106 | */ | ||
| 107 | public function fulltextIndexExists($tableName) | ||
| 121 | |||
| 122 | /** | ||
| 123 | * MSSQL stores the primary key column with an internal identifier, | ||
| 124 | * so a lookup needs to be done to determine it. | ||
| 125 | * | ||
| 126 | * @param string $tableName Name of table with primary key column "ID" | ||
| 127 | * @return string Internal identifier for primary key | ||
| 128 | */ | ||
| 129 | public function getPrimaryKey($tableName) | ||
| 142 | |||
| 143 | /** | ||
| 144 | * Gets the identity column of a table | ||
| 145 | * | ||
| 146 | * @param string $tableName | ||
| 147 | * @return string|null | ||
| 148 | */ | ||
| 149 | public function getIdentityColumn($tableName) | ||
| 163 | |||
| 164 | public function createDatabase($name) | ||
| 168 | |||
| 169 | public function dropDatabase($name) | ||
| 173 | |||
| 174 | public function databaseExists($name) | ||
| 184 | |||
| 185 | public function databaseList() | ||
| 189 | |||
| 190 | /** | ||
| 191 | * Create a new table. | ||
| 192 | * @param string $tableName The name of the table | ||
| 193 | * @param array $fields A map of field names to field types | ||
| 194 | * @param array $indexes A map of indexes | ||
| 195 | * @param array $options An map of additional options. The available keys are as follows: | ||
| 196 | * - 'MSSQLDatabase'/'MySQLDatabase'/'PostgreSQLDatabase' - database-specific options such as "engine" for MySQL. | ||
| 197 | * - 'temporary' - If true, then a temporary table will be created | ||
| 198 | * @param array $advancedOptions | ||
| 199 | * @return string The table name generated. This may be different from the table name, for example with temporary tables. | ||
| 200 | */ | ||
| 201 | public function createTable($tableName, $fields = null, $indexes = null, $options = null, $advancedOptions = null) | ||
| 235 | |||
| 236 | /** | ||
| 237 | * Alter a table's schema. | ||
| 238 | * @param string $tableName The name of the table to alter | ||
| 239 | * @param array $newFields New fields, a map of field name => field schema | ||
| 240 | * @param array $newIndexes New indexes, a map of index name => index type | ||
| 241 | * @param array $alteredFields Updated fields, a map of field name => field schema | ||
| 242 | * @param array $alteredIndexes Updated indexes, a map of index name => index type | ||
| 243 | * @param array $alteredOptions | ||
| 244 | * @param array $advancedOptions | ||
| 245 | */ | ||
| 246 | public function alterTable($tableName, $newFields = null, $newIndexes = null, $alteredFields = null, $alteredIndexes = null, $alteredOptions=null, $advancedOptions=null) | ||
| 285 | |||
| 286 | /** | ||
| 287 | * Given the table and column name, retrieve the constraint name for that column | ||
| 288 | * in the table. | ||
| 289 | * | ||
| 290 | * @param string $tableName Table name column resides in | ||
| 291 | * @param string $columnName Column name the constraint is for | ||
| 292 | * @return string|null | ||
| 293 | */ | ||
| 294 | public function getConstraintName($tableName, $columnName) | ||
| 303 | |||
| 304 | /** | ||
| 305 | * Given a table and column name, return a check constraint clause for that column in | ||
| 306 | * the table. | ||
| 307 | * | ||
| 308 | * This is an expensive query, so it is cached per-request and stored by table. The initial | ||
| 309 | * call for a table that has not been cached will query all columns and store that | ||
| 310 | * so subsequent calls are fast. | ||
| 311 | * | ||
| 312 | * @param string $tableName Table name column resides in | ||
| 313 | * @param string $columnName Column name the constraint is for | ||
| 314 | * @return string The check string | ||
| 315 | */ | ||
| 316 | public function getConstraintCheckClause($tableName, $columnName) | ||
| 342 | |||
| 343 | /** | ||
| 344 | * Return the name of the default constraint applied to $tableName.$colName. | ||
| 345 | * Will return null if no such constraint exists | ||
| 346 | * | ||
| 347 | * @param string $tableName Name of the table | ||
| 348 | * @param string $colName Name of the column | ||
| 349 | * @return string|null | ||
| 350 | */ | ||
| 351 | protected function defaultConstraintName($tableName, $colName) | ||
| 364 | |||
| 365 | /** | ||
| 366 | * Get enum values from a constraint check clause. | ||
| 367 | * | ||
| 368 | * @param string $clause Check clause to parse values from | ||
| 369 | * @return array Enum values | ||
| 370 | */ | ||
| 371 | protected function enumValuesFromCheckClause($clause) | ||
| 383 | |||
| 384 | /* | ||
| 385 | * Creates an ALTER expression for a column in MS SQL | ||
| 386 | * | ||
| 387 | * @param string $tableName Name of the table to be altered | ||
| 388 | * @param string $colName Name of the column to be altered | ||
| 389 | * @param string $colSpec String which contains conditions for a column | ||
| 390 | * @return string | ||
| 391 | */ | ||
| 392 | protected function alterTableAlterColumn($tableName, $colName, $colSpec) | ||
| 447 | |||
| 448 | public function renameTable($oldTableName, $newTableName) | ||
| 452 | |||
| 453 | /** | ||
| 454 | * Checks a table's integrity and repairs it if necessary. | ||
| 455 | * NOTE: MSSQL does not appear to support any vacuum or optimise commands | ||
| 456 | * | ||
| 457 | * @var string $tableName The name of the table. | ||
| 458 | * @return boolean Return true if the table has integrity after the method is complete. | ||
| 459 | */ | ||
| 460 | public function checkAndRepairTable($tableName) | ||
| 464 | |||
| 465 | public function createField($tableName, $fieldName, $fieldSpec) | ||
| 469 | |||
| 470 | /** | ||
| 471 | * Change the database type of the given field. | ||
| 472 | * @param string $tableName The name of the tbale the field is in. | ||
| 473 | * @param string $fieldName The name of the field to change. | ||
| 474 | * @param string $fieldSpec The new field specification | ||
| 475 | */ | ||
| 476 | public function alterField($tableName, $fieldName, $fieldSpec) | ||
| 480 | |||
| 481 | public function renameField($tableName, $oldName, $newName) | ||
| 485 | |||
| 486 | public function fieldList($table) | ||
| 585 | |||
| 586 | /** | ||
| 587 | * Create an index on a table. | ||
| 588 | * @param string $tableName The name of the table. | ||
| 589 | * @param string $indexName The name of the index. | ||
| 590 | * @param string $indexSpec The specification of the index, see SS_Database::requireIndex() for more details. | ||
| 591 | */ | ||
| 592 | public function createIndex($tableName, $indexName, $indexSpec) | ||
| 596 | |||
| 597 | /** | ||
| 598 | * Return SQL for dropping and recreating an index | ||
| 599 | * | ||
| 600 | * @param string $tableName Name of table to create this index against | ||
| 601 | * @param string $indexName Name of this index | ||
| 602 | * @param array|string $indexSpec Index specification, either as a raw string | ||
| 603 | * or parsed array form | ||
| 604 | * @return string The SQL required to generate this index | ||
| 605 | */ | ||
| 606 | protected function getIndexSqlDefinition($tableName, $indexName, $indexSpec) | ||
| 635 | |||
| 636 | public function alterIndex($tableName, $indexName, $indexSpec) | ||
| 640 | |||
| 641 | /** | ||
| 642 | * Return the list of indexes in a table. | ||
| 643 | * @param string $table The table name. | ||
| 644 | * @return array | ||
| 645 | */ | ||
| 646 | public function indexList($table) | ||
| 695 | |||
| 696 | /** | ||
| 697 | * For a given table name, get all the internal index names, | ||
| 698 | * except for those that are primary keys and fulltext indexes. | ||
| 699 | * | ||
| 700 | * @return array | ||
| 701 | */ | ||
| 702 | public function indexNames($tableName) | ||
| 711 | |||
| 712 | public function tableList() | ||
| 720 | |||
| 721 | /** | ||
| 722 | * Return a boolean type-formatted string | ||
| 723 | * We use 'bit' so that we can do numeric-based comparisons | ||
| 724 | * | ||
| 725 | * @param array $values Contains a tokenised list of info about this data type | ||
| 726 | * @return string | ||
| 727 | */ | ||
| 728 | public function boolean($values) | ||
| 733 | |||
| 734 | /** | ||
| 735 | * Return a date type-formatted string. | ||
| 736 | * | ||
| 737 | * @param array $values Contains a tokenised list of info about this data type | ||
| 738 | * @return string | ||
| 739 | */ | ||
| 740 | public function date($values) | ||
| 744 | |||
| 745 | /** | ||
| 746 | * Return a decimal type-formatted string | ||
| 747 | * | ||
| 748 | * @param array $values Contains a tokenised list of info about this data type | ||
| 749 | * @return string | ||
| 750 | */ | ||
| 751 | public function decimal($values) | ||
| 767 | |||
| 768 | /** | ||
| 769 | * Return a enum type-formatted string | ||
| 770 | * | ||
| 771 | * @param array $values Contains a tokenised list of info about this data type | ||
| 772 | * @return string | ||
| 773 | */ | ||
| 774 | public function enum($values) | ||
| 786 | |||
| 787 | /** | ||
| 788 |      * @todo Make this work like {@link MySQLDatabase::set()} | ||
| 789 | */ | ||
| 790 | public function set($values) | ||
| 794 | |||
| 795 | /** | ||
| 796 | * Return a float type-formatted string. | ||
| 797 | * | ||
| 798 | * @param array $values Contains a tokenised list of info about this data type | ||
| 799 | * @return string | ||
| 800 | */ | ||
| 801 | public function float($values) | ||
| 805 | |||
| 806 | /** | ||
| 807 | * Return a int type-formatted string | ||
| 808 | * | ||
| 809 | * @param array $values Contains a tokenised list of info about this data type | ||
| 810 | * @return string | ||
| 811 | */ | ||
| 812 | public function int($values) | ||
| 816 | |||
| 817 | /** | ||
| 818 | * Return a bigint type-formatted string | ||
| 819 | * | ||
| 820 | * @param array $values Contains a tokenised list of info about this data type | ||
| 821 | * @return string | ||
| 822 | */ | ||
| 823 | public function bigint($values) | ||
| 827 | |||
| 828 | /** | ||
| 829 | * Return a datetime type-formatted string | ||
| 830 | * For MS SQL, we simply return the word 'timestamp', no other parameters are necessary | ||
| 831 | * | ||
| 832 | * @param array $values Contains a tokenised list of info about this data type | ||
| 833 | * @return string | ||
| 834 | */ | ||
| 835 | public function datetime($values) | ||
| 839 | |||
| 840 | /** | ||
| 841 | * Return a text type-formatted string | ||
| 842 | * | ||
| 843 | * @param array $values Contains a tokenised list of info about this data type | ||
| 844 | * @return string | ||
| 845 | */ | ||
| 846 | public function text($values) | ||
| 852 | |||
| 853 | /** | ||
| 854 | * Return a time type-formatted string. | ||
| 855 | * | ||
| 856 | * @param array $values Contains a tokenised list of info about this data type | ||
| 857 | * @return string | ||
| 858 | */ | ||
| 859 | public function time($values) | ||
| 863 | |||
| 864 | /** | ||
| 865 | * Return a varchar type-formatted string | ||
| 866 | * | ||
| 867 | * @param array $values Contains a tokenised list of info about this data type | ||
| 868 | * @return string | ||
| 869 | */ | ||
| 870 | public function varchar($values) | ||
| 876 | |||
| 877 | /** | ||
| 878 | * Return a 4 digit numeric type. | ||
| 879 | * | ||
| 880 | * @param array $values | ||
| 881 | * @return string | ||
| 882 | */ | ||
| 883 | public function year($values) | ||
| 887 | |||
| 888 | /** | ||
| 889 | * This returns the column which is the primary key for each table | ||
| 890 | * | ||
| 891 | * @param bool $asDbValue | ||
| 892 | * @param bool $hasAutoIncPK | ||
| 893 | * @return string | ||
| 894 | */ | ||
| 895 | public function IdColumn($asDbValue = false, $hasAutoIncPK = true) | ||
| 905 | |||
| 906 | public function hasTable($tableName) | ||
| 913 | |||
| 914 | /** | ||
| 915 | * Returns the values of the given enum field | ||
| 916 | * NOTE: Experimental; introduced for db-abstraction and may changed before 2.4 is released. | ||
| 917 | * | ||
| 918 | * @param string $tableName | ||
| 919 | * @param string $fieldName | ||
| 920 | * @return array | ||
| 921 | */ | ||
| 922 | public function enumValuesForField($tableName, $fieldName) | ||
| 934 | |||
| 935 | /** | ||
| 936 | * This is a lookup table for data types. | ||
| 937 | * | ||
| 938 | * For instance, MSSQL uses 'BIGINT', while MySQL uses 'UNSIGNED' | ||
| 939 | * and PostgreSQL uses 'INT'. | ||
| 961 | 
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different sub-classes of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the parent class: