How To Override Core Files In Custom Module

Question

Hello I Have Created A Custom Module. In This Module I Have To Override Two Core Files.

And Do Some Changes in This FIles.

Path Is.

C:\xampp2\htdocs\mymagento\app\code\core\Mage\CatalogInventory\Model\Stock\Item.php C:\xampp2\htdocs\mymagento\app\code\core\Mage\CatalogInventory\Model\Observer.php

How To Do This? Pls Guide Me..

In The Core Observer File public function checkQuoteItemQty($observer) Function.

That Function I Have To Copy In My Custom module Observer.

Now, How Can I Override This Function in Config.xml?

Using Both The Observer File>

Answer 1

app/etc/modules/SR_Example.xml

<?xml version="1.0"?>
<config>
  <modules>
    <SR_Example>
      <active>true</active>
      <codePool>local</codePool>
      <version>0.1.0</version>
    </SR_Example>
  </modules>
</config>

app/code/local/SR/Example/etc/config.xml

<?xml version="1.0"?>
<config>
  <modules>
    <SR_Example>
      <version>0.1.0</version>
    </SR_Example>
  </modules>
  <global>
    <helpers>
      <example>
        <class>SR_Example_Helper</class>
      </example>
    </helpers>
    <models>
      <example>
        <class>SR_Example_Model</class>
        <resourceModel>example_mysql4</resourceModel>
      </example>
            <cataloginventory>
                <rewrite>
                    <stock_item>SR_Example_Model_CatalogInventory_Stock_Item</stock_item>
                </rewrite>
            </cataloginventory>
            <cataloginventory>
                <rewrite>
                    <observer>SR_Example_Model_CatalogInventory_Observer</observer>
                </rewrite>
            </cataloginventory>
    </models>
  </global>
</config> 

app/code/local/SR/Example/Helper/Data.php

class SR_Example_Helper_Data extends Mage_Core_Helper_Abstract
{
}

app/code/local/SR/Example/Model/CatalogInventory/Stock/Item.php

class SR_Example_Model_CatalogInventory_Stock_Item extends Mage_CatalogInventory_Model_Stock_Item
{
  // Your Override function
}

app/code/local/SR/Example/Model/CatalogInventory/Observer.php

class SR_Example_Model_CatalogInventory_Observer extends Mage_CatalogInventory_Model_Observer
{
   // Your Override function
}

Answer 2

<config>
    <global>
        <models>
            <tag>
                <rewrite>
                    <!-- Model -->
                    <tag>Inchoo_Tag_Model_Tag</tag>
                </rewrite>
            </tag>
            <tag_resource>
                <rewrite>
                    <!-- Resource -->
                    <tag>Inchoo_Tag_Model_Resource_Tag</tag>
                    <!-- Collection -->
                    <tag_collection>Inchoo_Tag_Model_Resource_Tag_Collection</tag_collection>
                </rewrite>
            </tag_resource>
        </models>
    </global>
</config>

this code override

app/code/local/Inchoo/Tag/Model/Tag.php
app/code/local/Inchoo/Tag/Model/Resource/Tag.php
app/code/local/Inchoo/Tag/Model/Resource/Tag/Collection.php.

change it with your file to work in your module

Answer 3

The most easy solution is to copy them to your local fold and make the changes there. In your case:

C:\xampp2\htdocs\mymagento\app\code\local\Mage\CatalogInventory\Model\Stock\Item.php C:\xampp2\htdocs\mymagento\app\code\local\Mage\CatalogInventory\Model\Observer.php