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  | 
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| 9 | class CacheMemcache extends CacheBase  | 
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| 10 | { | 
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| 11 | /**  | 
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| 12 | * instance of Memcahe  | 
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| 13 | * @var Memcahe  | 
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| 14 | */  | 
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| 15 | var $Memcache;  | 
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| 16 | var $SelectedExtension;  | 
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| 17 | |||
| 18 | /**  | 
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| 19 | * Get instance of CacheMemcache  | 
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| 20 | *  | 
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| 21 | * @param string $url url of memcache  | 
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| 22 | * @return CacheMemcache instance of CacheMemcache  | 
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| 23 | */  | 
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| 24 | function getInstance($url)  | 
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| 32 | |||
| 33 | /**  | 
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| 34 | * Construct  | 
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| 35 | *  | 
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| 36 | * Do not use this directly. You can use getInstance() instead.  | 
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| 37 | * @param string $url url of memcache  | 
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| 38 | * @return void  | 
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| 39 | */  | 
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| 40 | function CacheMemcache($url)  | 
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| 65 | |||
| 66 | /**  | 
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| 67 | * Return whether support or not support cache  | 
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| 68 | *  | 
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| 69 | * @return bool Return true on support or false on not support  | 
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| 70 | */  | 
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| 71 | function isSupport()  | 
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| 90 | |||
| 91 | /**  | 
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| 92 | * Get unique key of given key by path of XE  | 
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| 93 | *  | 
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| 94 | * @param string $key Cache key  | 
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| 95 | * @return string Return unique key  | 
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| 96 | */  | 
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| 97 | function getKey($key)  | 
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| 101 | |||
| 102 | /**  | 
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| 103 | * Store data at the server  | 
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| 104 | *  | 
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| 105 | * CacheMemcache::put() stores an item $buff with $key on the memcached server.  | 
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| 106 | * Parameter $valid_time is expiration time in seconds. If it's 0, the item never expires  | 
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| 107 | * (but memcached server doesn't guarantee this item to be stored all the time, it could be delete from the cache to make place for other items).  | 
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| 108 | *  | 
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| 109 | * Remember that resource variables (i.e. file and connection descriptors) cannot be stored in the cache,  | 
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| 110 | * because they can not be adequately represented in serialized state.  | 
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| 111 | *  | 
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| 112 | * @param string $key The key that will be associated with the item.  | 
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| 113 | * @param mixed $buff The variable to store. Strings and integers are stored as is, other types are stored serialized.  | 
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| 114 | * @param int $valid_time Expiration time of the item.  | 
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| 115 | * You can also use Unix timestamp or a number of seconds starting from current time, but in the latter case the number of seconds may not exceed 2592000 (30 days).  | 
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| 116 | * If it's equal to zero, use the default valid time CacheMemcache::valid_time.  | 
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| 117 | * @return bool Returns true on success or false on failure.  | 
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| 118 | */  | 
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| 119 | function put($key, $buff, $valid_time = 0)  | 
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| 134 | |||
| 135 | /**  | 
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| 136 | * Return whether cache is valid or invalid  | 
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| 137 | *  | 
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| 138 | * @param string $key Cache key  | 
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| 139 | * @param int $modified_time Unix time of data modified.  | 
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| 140 | * If stored time is older then modified time, the data is invalid.  | 
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| 141 | * @return bool Return true on valid or false on invalid.  | 
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| 142 | */  | 
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| 143 | View Code Duplication | function isValid($key, $modified_time = 0)  | 
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| 162 | |||
| 163 | /**  | 
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| 164 | * Retrieve item from the server  | 
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| 165 | *  | 
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| 166 | * CacheMemcache::get() returns previously stored data if an item with such $key exists on the server at this moment.  | 
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| 167 | *  | 
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| 168 | * @param string $key The key to fetch  | 
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| 169 | * @param int $modified_time Unix time of data modified.  | 
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| 170 | * If stored time is older then modified time, return false.  | 
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| 171 | * @return false|mixed Return false on failure or older then modified time. Return the string associated with the $key on success.  | 
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| 172 | */  | 
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| 173 | View Code Duplication | function get($key, $modified_time = 0)  | 
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| 192 | |||
| 193 | /**  | 
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| 194 | * Delete item from the server  | 
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| 195 | *  | 
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| 196 | * CacheMemcache::delete() deletes an item with tey $key.  | 
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| 197 | *  | 
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| 198 | * @param string $key The key associated with the item to delete.  | 
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| 199 | * @return void  | 
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| 200 | */  | 
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| 201 | function delete($key)  | 
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| 206 | |||
| 207 | /**  | 
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| 208 | * Delete item from the server(private)  | 
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| 209 | *  | 
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| 210 | * @see CacheMemcache::delete()  | 
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| 211 | * @param string $_key The key associated with the item to delete.  | 
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| 212 | * @return void  | 
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| 213 | */  | 
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| 214 | function _delete($_key)  | 
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| 218 | |||
| 219 | /**  | 
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| 220 | * Flush all existing items at the server  | 
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| 221 | *  | 
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| 222 | * CacheMemcache::truncate() immediately invalidates all existing items.  | 
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| 223 | * CacheMemcache::truncate() doesn't actually free any resources, it only marks all the items as expired,  | 
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| 224 | * so occupied memory will be overwitten by new items.  | 
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| 225 | *  | 
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| 226 | * @return bool Returns true on success or false on failure.  | 
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| 227 | */  | 
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| 228 | function truncate()  | 
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| 232 | |||
| 233 | }  | 
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| 234 | /* End of file CacheMemcache.class.php */  | 
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| 236 |