Overwriting a modules overwritten extended class

Question

I've created a quick module to extend Mage_Catalog_Block_Layer_View Class::getFilterableAttributes() which works just fine.

However I need the funtioality of Amastys improved navigation module aswell which sacks off the getFilterableAttributes method for it's own _getFilterableAttributes method.

Now I can easily set a depends on my module to load first however I'm getting confused as the class that defines the _getFilterableAttributes method doesn't extend a Magento base class, it extends an abstract that in turn extends another class.

/Model/Catalog/Layer.php

class Test_BrandCategories_Model_Catalog_Layer extends Mage_Catalog_Model_Layer
{

    protected function _getFilterableAttributes()
    {
        Mage::log('Running...', null, 'ahoy_brand.log');

        $attributes = $this->getData('_filterable_attributes');
        if (is_null($attributes)) {
            $settings   = $this->_getDataHelper()->getAttributesSettings();
            $attributes = Mage::helper('amshopby/attributes')->getFilterableAttributes();
            foreach ($attributes as $k => $v){
                $pos = 'left';
                if (isset($settings[$v->getId()])){
                    $pos = $settings[$v->getId()]->getBlockPos();
                }
                elseif($v->getAttributeCode() == 'price'){
                    $pos = Mage::getStoreConfig('amshopby/block/price_pos');
                }
                if ($this->_notInBlock($pos)){
                    unset($attributes[$k]);
                }
            }

            $this->setData('_filterable_attributes', $attributes);
        }

        return $attributes;
    }
}

Amasty/Shopby/Block/Catalog/Layer/View.php

class Amasty_Shopby_Block_Catalog_Layer_View extends Amasty_Shopby_Block_Catalog_Layer_View_Adapter
{

    ...

    protected function _getFilterableAttributes()
    {
        $attributes = $this->getData('_filterable_attributes');
        if (is_null($attributes)) {
            $settings   = $this->_getDataHelper()->getAttributesSettings();
            $attributes = Mage::helper('amshopby/attributes')->getFilterableAttributes();
            foreach ($attributes as $k => $v){
                $pos = 'left';
                if (isset($settings[$v->getId()])){
                    $pos = $settings[$v->getId()]->getBlockPos();
                }
                elseif($v->getAttributeCode() == 'price'){
                    $pos = Mage::getStoreConfig('amshopby/block/price_pos');                    
                }
                if ($this->_notInBlock($pos)){
                    unset($attributes[$k]);
                }
            } 

            $this->setData('_filterable_attributes', $attributes);
        }

        return $attributes;
    }

    ...

}

Amasty/Shopby.Block/Catalog/Layer/View/Adapter.php

if (Mage::helper('amshopby')->useSolr()) {
    class Amasty_Shopby_Block_Catalog_Layer_View_Adapter extends Enterprise_Search_Block_Catalog_Layer_View {}
} else {
    class Amasty_Shopby_Block_Catalog_Layer_View_Adapter extends Mage_Catalog_Block_Layer_View {}
}

Because of this extended extension and the custom method name pretended with an _ I'm really not sure what to do, I really don;t want to modify the Amasty plugin if possible but i know I may need to comment out the offending function or something similar. But after looking up solutions for a while I've not found an example that features a nested extension.

Answer 1

Perhaps you could do some nesting yourself: Extend your module's class from Amasty's class instead of the Mage Core.

    class Test_BrandCategories_Model_Catalog_Layer extends Amasty_Shopby_Block_Catalog_Layer_View

That way you maintain the functionality of Amasty's extension but you can change the "offending function"