Zarr domain

This class implements a basic domain object for Zarr stores. Domains are specific encodings for a certain domain of application. These encodings are included in the attributes of the Zarr groups and arrays and need custom code (usually in the form of another package) to interpret the attributes and properly process array data. Domains can be fully application-specific or they can implement one or more published Zarr conventions.

Domains have to be registered with this package to become available to the processing pipeline. Domain code is then called automatically when a Zarr store is opened for all groups and arrays in the store.

New domains need to inherit from this base class and implement all of the relevant methods. New domains may have additional methods specific to the domain of the data. It is generally not useful to directly instantiate this class: for a Zarr store without a registered domain an instance of this class is initialized automatically.

Active bindings

name

(read-only) The name of the domain.

can_read

(read-only) Flag to indicate if this domain can read a Zarr store using this domain. Should always be TRUE.

can_write

(read-only) Flag to indicate if this domain can write a Zarr store using this domain. TRUE for a generic Zarr store; other domains may report `FALSE.

Methods

Public methods

• zarr_domain$new()

• zarr_domain$build()

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Method new()

Create a new instance of a Zarr domain. This method should not be called directly (as in zarr_domain$new()); instead, descendant classes will call this method in their initialization code.

Usage

zarr_domain$new(name)

Arguments

name

Character string giving the name of the domain. This may be any sensible string value. The name of the domain must be unique in the session or an error will be thrown upon registering the domain.

Returns

A new instance of a domain class.

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Method build()

This method will be called when the domain is requested to asses the Zarr node for domain properties. This method must be implemented by descendant classes and return an appropriate node if it will manage the node. The code should be agile and return swiftly so any non-trivial operations should be left to a later moment, for instance when the node is accessed by the application or end-user.

Usage

zarr_domain$build(name, metadata, parent, store)

Arguments

name

The name of the node.

metadata

List with the metadata of the node.

parent

The parent node of this new node. May be NULL for a root node.

store

The store to persist data in.

Returns

A zarr_node descendant, typically an instance of a domain-specific descendant class of zarr_array or zarr_group. If the domain does not want to manage the node, return FALSE.