Setting cache lifetime on collections

Question

I would like to know how we can control the cache lifetime on a collection.

Here's how I initialize caching on my collection:

public function _construct() 
{
    ...

    // Configure collection cache
    $this->initCache(
        Mage::app()->getCacheInstance(),
        'MY_COLLECTION',
        array(Namespace_Module_Model_Something::CACHE_TAG)
    );
    parent::_construct();
}

Where the cache instance comes from Mage_Core_Model_Cache. I can see how its frontend model is created out of Zend_Cache_Core -- whose class provides a cache lifetime setter. But this does not appear to solve my problem.

I'm using APC caching on the backend, and that's what I want to modify when the cache entry is written. And I'd like to be able to control this per collection (as in the constructor shown above).

Is this possible?

Answer 1

Well, I figured it out. Was simpler than I expected.

The clue came out of Mage::app()->saveCache(), which is simple a wrapper method for the cache model's save routine:

$this->_cache->save($data, $id, $tags, $lifeTime);

When I noticed the $lifeTime parameter, it dawned on me that the save method accepts a fourth param * facepalm * -- well, hopefully this helps someone.