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:
| 1 | <?php | ||
| 15 | class Requests_Utility_CaseInsensitiveDictionary implements ArrayAccess, IteratorAggregate { | ||
| 16 | /** | ||
| 17 | * Actual item data | ||
| 18 | * | ||
| 19 | * @var array | ||
| 20 | */ | ||
| 21 | protected $data = array(); | ||
| 22 | |||
| 23 | /** | ||
| 24 | * Creates a case insensitive dictionary. | ||
| 25 | * | ||
| 26 | * @param array $data Dictionary/map to convert to case-insensitive | ||
| 27 | */ | ||
| 28 | 	public function __construct(array $data = array()) { | ||
| 33 | |||
| 34 | /** | ||
| 35 | * Check if the given item exists | ||
| 36 | * | ||
| 37 | * @param string $key Item key | ||
| 38 | * @return boolean Does the item exist? | ||
| 39 | */ | ||
| 40 | 	public function offsetExists($key) { | ||
| 44 | |||
| 45 | /** | ||
| 46 | * Get the value for the item | ||
| 47 | * | ||
| 48 | * @param string $key Item key | ||
| 49 | * @return string Item value | ||
| 50 | */ | ||
| 51 | View Code Duplication | 	public function offsetGet($key) { | |
| 59 | |||
| 60 | /** | ||
| 61 | * Set the given item | ||
| 62 | * | ||
| 63 | * @throws Requests_Exception On attempting to use dictionary as list (`invalidset`) | ||
| 64 | * | ||
| 65 | * @param string $key Item name | ||
| 66 | * @param string $value Item value | ||
| 67 | */ | ||
| 68 | 	public function offsetSet($key, $value) { | ||
| 76 | |||
| 77 | /** | ||
| 78 | * Unset the given header | ||
| 79 | * | ||
| 80 | * @param string $key | ||
| 81 | */ | ||
| 82 | 	public function offsetUnset($key) { | ||
| 85 | |||
| 86 | /** | ||
| 87 | * Get an iterator for the data | ||
| 88 | * | ||
| 89 | * @return ArrayIterator | ||
| 90 | */ | ||
| 91 | 	public function getIterator() { | ||
| 94 | |||
| 95 | /** | ||
| 96 | * Get the headers as an array | ||
| 97 | * | ||
| 98 | * @return array Header data | ||
| 99 | */ | ||
| 100 | 	public function getAll() { | ||
| 103 | } | ||
| 104 | 
You can fix this by adding a namespace to your class:
When choosing a vendor namespace, try to pick something that is not too generic to avoid conflicts with other libraries.