PHP code example of exteon / identity-cache

    
        
<?php
require_once('vendor/autoload.php');

/* Start to develop here. Best regards https://php-download.com/ */

    

exteon / identity-cache example snippets

$map = new \Exteon\IdentityCache\WeakReference\IdentityMap();

$instance = new stdClass();
$map[1] = $instance;

// While object is in use via $instance, the map will provide a reference to it
// via its id.

assert($map[1] === $instance);

// Put object out of use by releasing its reference

unset($instance);

// Object has been freed and its reference unset, because all references to it
// were released

assert(isset($map[1]) === false);

$cache = new \Exteon\IdentityCache\WeakReference\IdentityCache([
    'trigger' => 'maxRetainedObjects',
    'maxRetainedObjects' => 1,
    'purgeStrategy' => 'popularity',
    'purgePressure' => 50
]);

// Create 2 object instances

$instance1 = new stdClass();
$instance2 = new stdClass();

$cache[1] = $instance1;
$cache[2] = $instance2;

// While objects are in use via $instance1, $instance2, the map holds references
// to them via their ids

assert($cache[1] === $instance1);
assert($cache[1] === $instance1);

// Increase instance 1's popularity by accessing it repeatedly

$cache[1];
$cache[1];
$cache[1];

// Put objects out of use by releasing their references

unset($instance1);
unset($instance2);

// maxRetainedObjects was configured to 1; instances will be purged

$cache->gc();

// instance 1's popularity was greater so it was preserved in the cache

assert(is_object($cache[1]));

// instance 2 was of a lesser popularity so it was purged

assert(isset($cache[2]) === false);

use \Exteon\IdentityCache\WeakReference\IdentityCache;

$cache = new IdentityCache([
    //  Specifies the condition that triggers the cache to purge unused 
    //  references.
    //  Possible values:
    //      'maxRetainedObjects'    :   purging will be initiated when we are
    //                                  caching a number of references greater
    //                                  than the maxRetainedObjects parameter
    //      'maxScriptMemory'       :   purging will be initiated when the total
    //                                  memory consumed by the running script is
    //                                  greater than the value specified in the
    //                                  maxScriptMemory parameter.
    //      'none'                  :   purging will not be done. This can be
    //                                  changed later by using the setConfig()
    //                                  method.
    'trigger' => 'maxRetainedObjects',

    //  Number of objects that can be retained before purging if trigger is
    //  set to 'maxRetainedObjects'
    'maxRetainedObjects' => 1000,

    //  Maximum total memory consumed by the running script before purging if
    //  trigger is 'maxScriptMemory'. Format is the same as php.ini's sizes// 
    //  format.
    'maxScriptMemory' => '64M',

    //  When purging, which percent of the cached objects to purge?
    'purgePressure' => 10,

    //  When purging, how to select which instances to keep?
    //  Possible values:
    //      'popularity'    :   Keep the most popular objects. See the following 
    //                          section for more details on how popularity-based
    //                          caching works.
    //      'random'        :   Randomly purge the number of objects dictated
    //                          by purgePressure.  
    'purgeStrategy' => 'popularity',

    //  See the Popularity-based caching section for an explanation of this// 
    //  parameter
    'popularityDecay' => IdentityCache::getPopularityDecay(1000, 10000, 2)
]);

$popularityDecay = \Exteon\IdentityCache\WeakReference\IdentityCache::getPopularityDecay(
    1000,   //  initialPopularity
    10000,  //  rounds
    2       //  targetPopularity
);

$cache = new \Exteon\IdentityCache\WeakReference\IdentityCache([
    'trigger' => 'maxRetainedObjects',
    'maxRetainedObjects' => 0
]);

$instance = new stdClass();
$cache[1] = $instance;

$instance->foo = 'bar';
$cache->acquire(1);

//  The acquired identity with id 1 will never be purged, even if the cache's
//  purge strategy is triggered by number of objects or memory trigger 

unset($instance);
$cache->gc();
assert(
    is_object($cache[1]) &&
    $cache[1]->foo === 'bar'
);

//  Acquired identities can be released and then they can be purged if no longer 
//  in use:

$cache->release(1);
$cache->gc();
assert(isset($cache[1]) === false);