Use the static method set() to store an entry in the registry.

Zend_Registry::set('index', $value);

The value returned can be an object, an array, or a scalar. You can change the value stored in a specific entry of the registry by calling the set() method to set the entry to a new value.

The index can be a scalar (NULL, string, or number), like an ordinary array.

To retrieve an entry from the registry, use the static get() method.

$value = Zend_Registry::get('index');

The getInstance() method returns the singleton registry object. This registry object is iterable, making all values stored in the registry easily accessible.

$registry = Zend_Registry::getInstance();

foreach ($registry as $index => $value) {
    echo "Registry index $index contains:\n";
    var_dump($value);
}

In addition to accessing the static registry via static methods, you can create an instance directly and use it as an object.

The registry instance you access through the static methods is simply one such instance. It is for convenience that it is stored statically, so that it is accessible from anywhere in an application.

Use the traditional new operator to instantiate Zend_Registry. Instantiating Zend_Registry using its constructor also makes initializing the entries in the registry simple by taking an associative array as an argument.

$registry = new Zend_Registry(array('index' => $value));

Once such a Zend_Registry object is instantiated, you can use it by calling any array object method or by setting it as the singleton instance for Zend_Registry with the static method setInstance().

$registry = new Zend_Registry(array('index' => $value));

Zend_Registry::setInstance($registry);

The setInstance() method throws a Zend_Exception if the static registry has already been initialized.

If you have several values to get or set, you may find it convenient to access the registry with array notation.

$registry = Zend_Registry::getInstance();

$registry['index'] = $value;

var_dump( $registry['index'] );

You may also find it convenient to access the registry in an object-oriented fashion by using index names as object properties. You must specifically construct the registry object using the ArrayObject::ARRAY_AS_PROPS option and initialize the static instance to enable this functionality.

// in your application bootstrap:
$registry = new Zend_Registry(array(), ArrayObject::ARRAY_AS_PROPS)
Zend_Registry::setInstance($registry);
$registry->tree = 'apple';

.
.
.

// in a different function, elsewhere in your application:
$registry = Zend_Registry::getInstance();

echo $registry->tree; // echo's "apple"

$registry->index = $value;

var_dump($registry->index);

To find out if a particular index in the registry has been set, use the static method isRegistered().

if (Zend_Registry::isRegistered($index)) {
    $value = Zend_Registry::get($index);
}

To find out if a particular index in a registry array or object has a value, use the isset() function as you would with an ordinary array.

$registry = Zend_Registry::getInstance();

// using array access syntax
if (isset($registry['index'])) {
    var_dump( $registry['index'] );
}

// using object access syntax
if (isset($registry->index)) {
    var_dump( $registry->index );
}

The static registry is an instance of the class Zend_Registry. If you want to add functionality to the registry, you should create a class that extends Zend_Registry and specify this class to instantiate for the singleton in the static registry. Use the static method setClassName() to specify the class.

Zend_Registry::setClassName('My_Registry');

Zend_Registry::set('index', $value);

The registry throws a Zend_Exception if you attempt to set the classname after the registry has been accessed for the first time. It is therefore recommended that you specify the class name for your static registry in your application bootstrap.

Although it is not normally necessary, you can unset the singleton instance of the registry, if desired. Use the static method _unsetInstance() to do so.

You might use this method, for example, if you want to use setInstance() or setClassName() after the singleton registry object has been initialized. Unsetting the singleton instance allows you to use these methods even after the singleton registry object has been set. Using Zend_Registry in this manner is not recommended for typical applications and environments.

Zend_Registry::set('index', $value);

Zend_Registry::_unsetInstance();

// change the class
Zend_Registry::setClassName('My_Registry');

Zend_Registry::set('index', $value);