# Customizing Zend_Queue

## Creating your own adapter

Zend_Queue will accept any adapter that implements Zend_Queue_Adapter_AdapterAbstract. You can create your own adapter by extending one of the existing adapters, or the abstract class Zend_Queue_Adapter_AdapterAbstract. I suggest reviewing Zend_Queue_Adapter_Array as this adapter is the easiest to conceptualize.

    class Custom_DbForUpdate extends Zend_Queue_Adapter_Db
    {
        /**
         * @see code in tests/Zend/Queue/Custom/DbForUpdate.php
         *
         * Custom_DbForUpdate uses the SELECT ... FOR UPDATE to find it's rows.
         * this is more likely to produce the wanted rows than the existing code.
         *
         * However, not all databases have SELECT ... FOR UPDATE as a feature.
         *
         * Note: this was later converted to be an option for Zend_Queue_Adapter_Db
         *
         * This code still serves as a good example.
         */
    }

    $options = array(
        'name'          => 'queue1',
        'driverOptions' => array(
            'host'      => '127.0.0.1',
            'port'      => '3306',
            'username'  => 'queue',
            'password'  => 'queue',
            'dbname'    => 'queue',
            'type'      => 'pdo_mysql'
        )
    );

    $adapter = new Custom_DbForUpdate($options);
    $queue = new Zend_Queue($adapter, $options);

You can also change the adapter on the fly as well.

    $adapter = new MyCustom_Adapter($options);
    $queue   = new Zend_Queue($options);
    $queue->setAdapter($adapter);
    echo "Adapter: ", get_class($queue->getAdapter()), "\n";

or

    $options = array(
        'name'           => 'queue1',
        'namespace'      => 'Custom',
        'driverOptions'  => array(
            'host'       => '127.0.0.1',
            'port'       => '3306',
            'username'   => 'queue',
            'password'   => 'queue',
            'dbname'     => 'queue',
            'type'       => 'pdo_mysql'
        )
    );
    $queue = new Zend_Queue('DbForUpdate', $config); // loads Custom_DbForUpdate

## Creating your own message class

Zend_Queue will also accept your own message class. Our variables start with an underscore. For example:

    class Zend_Queue_Message
    {
        protected $_data = array();
    }

You can extend the existing messaging class. See the example code in `tests/Zend/Queue/Custom/Message.php`.

## Creating your own message iterator class

Zend_Queue will also accept your own message iterator class. The message iterator class is used to return messages from Zend_Queue_Adapter_Abstract::recieve(). Zend_Queue_Abstract::receive() should always return a container class like Zend_Queue_Message_Iterator, even if there is only one message.

See the example filename in `tests/Zend/Queue/Custom/Messages.php`.

## Creating your own queue class

Zend_Queue can also be overloaded easily.

See the example filename in `tests/Zend/Queue/Custom/Queue.php`.