Formatter¶

class lsst.daf.butler.Formatter(fileDescriptor=None)¶

Interface for reading and writing Datasets with a particular StorageClass.

Parameters:	fileDescriptor : `FileDescriptor`, optional Identifies the file to read or write, and the associated storage classes and parameter information. Its value can be `None` if the caller will never call `Formatter.read` or `Formatter.write`.

Attributes Summary

`fileDescriptor`	FileDescriptor associated with this formatter (`Formatter`, read-only)
`unsupportedParameters`	Set of parameters not understood by this `Formatter`.

Methods Summary

`name`()	Returns the fully qualified name of the formatter.
`predictPath`()	Return the path that would be returned by write, without actually writing.
`predictPathFromLocation`(location)	Return the path that would be returned by write, without actually writing.
`read`([component])	Read a Dataset.
`segregateParameters`([parameters])	Segregate the supplied parameters into those understood by the formatter and those not understood by the formatter.
`write`(inMemoryDataset)	Write a Dataset.

Attributes Documentation

fileDescriptor¶: FileDescriptor associated with this formatter (Formatter, read-only)

unsupportedParameters = frozenset()¶: Set of parameters not understood by this Formatter. An empty set means all parameters are supported. None indicates that no parameters are supported (frozenset).

Methods Documentation

classmethod name()¶

Returns the fully qualified name of the formatter.

Returns:	name : `str` Fully-qualified name of formatter class.

predictPath()¶

Return the path that would be returned by write, without actually writing.

Uses the FileDescriptor associated with the instance.

Returns:	path : `str` Path within datastore that would be associated with the location stored in this `Formatter`.

classmethod predictPathFromLocation(location)¶

Return the path that would be returned by write, without actually writing.

Parameters:	location : `Location` Location of file for which path prediction is required.
Returns:	path : `str` Path within datastore that would be associated with this location.

read(component=None)¶

Read a Dataset.

Parameters:	component : `str`, optional Component to read from the file. Only used if the `StorageClass` for reading differed from the `StorageClass` used to write the file.
Returns:	inMemoryDataset : `object` The requested Dataset.

segregateParameters(parameters=None)¶

Segregate the supplied parameters into those understood by the formatter and those not understood by the formatter.

Any unsupported parameters are assumed to be usable by associated assemblers.

Parameters:	parameters : `dict`, optional Parameters with values that have been supplied by the caller and which might be relevant for the formatter. If `None` parameters will be read from the registered `FileDescriptor`.
Returns:	supported : `dict` Those parameters supported by this formatter. unsupported : `dict` Those parameters not supported by this formatter.

write(inMemoryDataset)¶

Write a Dataset.

Parameters:	inMemoryDataset : `object` The Dataset to store.
Returns:	path : `str` The path to where the Dataset was stored within the datastore.