Framework

Zend_Queue

Framework

The Zend_Queue is a proxy that hides the details of the queue services. The queue services are represented by Zend_Queue_Adapter_<service>. For example, Zend_Queue_Adapter_Db is a queue that will use database tables to store and retrieve messages.

Below is an example for using database tables for a queuing system:

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

// Create a database queue.
// Zend_Queue will prepend Zend_Queue_Adapter_ to 'Db' for the class name.
$queue = new Zend_Queue('Db', $options);

The Zend_Queue constructor will create a Zend_Queue_Adapter_Db and initialize the adapter with the configuration settings.

The accepted configuration settings for each adapter are provided in the adapter notes.

Zend_Queue returns messages using the class Zend_Queue_Message_Iterator, which is an implementation of SPL Iterator and Countable. Zend_Queue_Message_Iterator contains an array of Zend_Queue_Message objects.

$messages = $queue->receive(5);
foreach ($messages as $i => $message) {
    echo "$i) Message => ", $message->body, "\n";
}

Any exceptions thrown are of class Zend_Queue_Exception.

Introduction

Zend_Queue is a proxy class that represents an adapter.

The send(), count($queue), and receive() methods are employed by each adapter to interact with queues.

The createQueue(), deleteQueue() methods are used to manage queues.

Commonality among adapters

The queue services supported by Zend_Queue do not all support the same functions. For example, Zend_Queue_Adapter_Array, Zend_Queue_Adapter_Db, support all functions, while Zend_Queue_Adapter_Activemq does not support queue listing, queue deletion, or counting of messages.

You can determine what functions are supported by using Zend_Queue::isSupported() or Zend_Queue::getCapabilities().

createQueue() - create a queue
deleteQueue() - delete a queue
send() - send a message

send() is not available in all adapters; the Zend_Queue_Adapter_Null does not support send().
receive() - receive messages

receive() is not available in all adapters; the Zend_Queue_Adapter_Null does not support receive().
deleteMessage() - delete a message
count() - count the number of messages in a queue
isExists() - checks the existence of a queue

receive() methods are employed by each adapter to interact with queues.

The createQueue() and deleteQueue() methods are used to manage queues.

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Example usage