# Other Operations

You can get the size of a repository using size() method. It returns the number of entities in the repository.

long size = productRepository.size();

You can clear all the entities from a repository using clear() method. It removes all the entities from the repository and index entries from the indexes. It does not drop the repository.

productRepository.clear();

You can drop a repository using drop() method. It removes all the entities from the repository and index entries from the indexes. It also drops all the indexes associated with the repository. It also removes the repository from the database.

productRepository.drop();

You can call isDropped() method to check if the repository is dropped or not.

boolean isDropped = productRepository.isDropped();

You can close a repository using close() method. Any further operation on a closed repository will throw NitriteIOException.

productRepository.close();

After closing a repository, you must re-open it via Nitrite.getRepository() method to perform any operation on it.

You can call isOpen() method to check if the repository is closed or not.

boolean isOpen = productRepository.isOpen();

You can register an event listener on a repository to get notified on entity changes. The event listener must implement CollectionEventListener interface. It will receive CollectionEventInfo whenever an entity is inserted, updated or removed from the repository.

productRepository.subscribe(eventInfo -> {
    // do something with the eventInfo
});

You can also remove an event listener from a collection.

productRepository.unsubscribe(listener);

More on CollectionEventInfo can be found here.

Attributes is a metadata information associated with a repository.

You can get/set attributes on a repository. The attributes are stored in the database and can be retrieved later. The attributes are stored in a special map named $nitrite_meta_map.

// get the attributes
Attributes attributes = productRepository.getAttributes();
attributes.set("key", "value");

// save the attributes
productRepository.setAttributes(attributes);

// get the attributes
attributes = productRepository.getAttributes();

// get the value of a key
String value = attributes.get("key");

Processor can be used to process the underlying documents of a repository. More on processors can be found here.

You can register a processor on a repository using addProcessor() method. It takes a Processor as input parameter.

// create a processor
MyProcessor processor = new MyProcessor();

// process existing entities
processor.process(productRepository);

// register the processor
productRepository.addProcessor(processor);

Nitrite provides a StringFieldEncryptionProcessor which can be used to encrypt a field before writing it into a repository and decrypt a field after reading it from a repository.

More on this is described in Support.