lsst.pex.config gc9a196ae7d+380a6a509b
Public Member Functions | Public Attributes | Static Public Attributes | List of all members
lsst.pex.config.configChoiceField.ConfigChoiceField Class Reference
Inheritance diagram for lsst.pex.config.configChoiceField.ConfigChoiceField:
lsst.pex.config.config.Field lsst.pex.config.registry.RegistryField

Public Member Functions

def __init__ (self, doc, typemap, default=None, optional=False, multi=False, deprecated=None)
 
def __get__ (self, instance, owner=None)
 
def __set__ (self, instance, value, at=None, label="assignment")
 
def rename (self, instance)
 
def validate (self, instance)
 
def toDict (self, instance)
 
def freeze (self, instance)
 
def save (self, outfile, instance)
 
def __deepcopy__ (self, memo)
 
- Public Member Functions inherited from lsst.pex.config.config.Field
def __delete__ (self, instance, at=None, label="deletion")
 

Public Attributes

 typemap
 
 multi
 
- Public Attributes inherited from lsst.pex.config.config.Field
 dtype
 
 doc
 
 deprecated
 
 default
 
 check
 
 optional
 
 source
 

Static Public Attributes

 instanceDictClass = ConfigInstanceDict
 
- Static Public Attributes inherited from lsst.pex.config.config.Field
 supportedTypes = set((str, bool, float, int, complex))
 

Detailed Description

A configuration field (`~lsst.pex.config.Field` subclass) that allows a
user to choose from a set of `~lsst.pex.config.Config` types.

Parameters
----------
doc : `str`
    Documentation string for the field.
typemap : `dict`-like
    A mapping between keys and `~lsst.pex.config.Config`-types as values.
    See *Examples* for details.
default : `str`, optional
    The default configuration name.
optional : `bool`, optional
    When `False`, `lsst.pex.config.Config.validate` will fail if the
    field's value is `None`.
multi : `bool`, optional
    If `True`, the field allows multiple selections. In this case, set the
    selections by assigning a sequence to the ``names`` attribute of the
    field.

    If `False`, the field allows only a single selection. In this case,
    set the active config by assigning the config's key from the
    ``typemap`` to the field's ``name`` attribute (see *Examples*).
deprecated : None or `str`, optional
    A description of why this Field is deprecated, including removal date.
    If not None, the string is appended to the docstring for this Field.

See also
--------
ChoiceField
ConfigDictField
ConfigField
ConfigurableField
DictField
Field
ListField
RangeField
RegistryField

Notes
-----
``ConfigChoiceField`` instances can allow either single selections or
multiple selections, depending on the ``multi`` parameter. For
single-selection fields, set the selection with the ``name`` attribute.
For multi-selection fields, set the selection though the ``names``
attribute.

This field is validated only against the active selection. If the
``active`` attribute is `None` and the field is not optional, validation
will fail.

When saving a configuration with a ``ConfigChoiceField``, the entire set is
saved, as well as the active selection.

Examples
--------
While the ``typemap`` is shared by all instances of the field, each
instance of the field has its own instance of a particular sub-config type.

For example, ``AaaConfig`` is a config object

>>> from lsst.pex.config import Config, ConfigChoiceField, Field
>>> class AaaConfig(Config):
...     somefield = Field("doc", int)
...

The ``MyConfig`` config has a ``ConfigChoiceField`` field called ``choice``
that maps the ``AaaConfig`` type to the ``"AAA"`` key:

>>> TYPEMAP = {"AAA", AaaConfig}
>>> class MyConfig(Config):
...     choice = ConfigChoiceField("doc for choice", TYPEMAP)
...

Creating an instance of ``MyConfig``:

>>> instance = MyConfig()

Setting value of the field ``somefield`` on the "AAA" key of the ``choice``
field:

>>> instance.choice['AAA'].somefield = 5

**Selecting the active configuration**

Make the ``"AAA"`` key the active configuration value for the ``choice``
field:

>>> instance.choice = "AAA"

Alternatively, the last line can be written:

>>> instance.choice.name = "AAA"

(If the config instance allows multiple selections, you'd assign a sequence
to the ``names`` attribute instead.)

``ConfigChoiceField`` instances also allow multiple values of the same
type:

>>> TYPEMAP["CCC"] = AaaConfig
>>> TYPEMAP["BBB"] = AaaConfig

Constructor & Destructor Documentation

◆ __init__()

def lsst.pex.config.configChoiceField.ConfigChoiceField.__init__ (   self,
  doc,
  typemap,
  default = None,
  optional = False,
  multi = False,
  deprecated = None 
)

Reimplemented from lsst.pex.config.config.Field.

Member Function Documentation

◆ __deepcopy__()

def lsst.pex.config.configChoiceField.ConfigChoiceField.__deepcopy__ (   self,
  memo 
)
Customize deep-copying, because we always want a reference to the
original typemap.

WARNING: this must be overridden by subclasses if they change the
constructor signature!

Reimplemented in lsst.pex.config.registry.RegistryField.

◆ __get__()

def lsst.pex.config.configChoiceField.ConfigChoiceField.__get__ (   self,
  instance,
  owner = None 
)
Define how attribute access should occur on the Config instance
This is invoked by the owning config object and should not be called
directly

When the field attribute is accessed on a Config class object, it
returns the field object itself in order to allow inspection of
Config classes.

When the field attribute is access on a config instance, the actual
value described by the field (and held by the Config instance) is
returned.

Reimplemented from lsst.pex.config.config.Field.

◆ __set__()

def lsst.pex.config.configChoiceField.ConfigChoiceField.__set__ (   self,
  instance,
  value,
  at = None,
  label = "assignment" 
)
Set an attribute on the config instance.

Parameters
----------
instance : `lsst.pex.config.Config`
    The config instance that contains this field.
value : obj
    Value to set on this field.
at : `list` of `lsst.pex.config.callStack.StackFrame`
    The call stack (created by
    `lsst.pex.config.callStack.getCallStack`).
label : `str`, optional
    Event label for the history.

Notes
-----
This method is invoked by the owning `lsst.pex.config.Config` object
and should not be called directly.

Derived `~lsst.pex.config.Field` classes may need to override the
behavior. When overriding ``__set__``, `~lsst.pex.config.Field` authors
should follow the following rules:

- Do not allow modification of frozen configs.
- Validate the new value **before** modifying the field. Except if the
  new value is `None`. `None` is special and no attempt should be made
  to validate it until `lsst.pex.config.Config.validate` is called.
- Do not modify the `~lsst.pex.config.Config` instance to contain
  invalid values.
- If the field is modified, update the history of the
  `lsst.pex.config.field.Field` to reflect the changes.

In order to decrease the need to implement this method in derived
`~lsst.pex.config.Field` types, value validation is performed in the
`lsst.pex.config.Field._validateValue`. If only the validation step
differs in the derived `~lsst.pex.config.Field`, it is simpler to
implement `lsst.pex.config.Field._validateValue` than to reimplement
``__set__``. More complicated behavior, however, may require
reimplementation.

Reimplemented from lsst.pex.config.config.Field.

◆ freeze()

def lsst.pex.config.configChoiceField.ConfigChoiceField.freeze (   self,
  instance 
)
Make this field read-only (for internal use only).

Parameters
----------
instance : `lsst.pex.config.Config`
    The config instance that contains this field.

Notes
-----
Freezing is only relevant for fields that hold subconfigs. Fields which
hold subconfigs should freeze each subconfig.

**Subclasses should implement this method.**

Reimplemented from lsst.pex.config.config.Field.

◆ rename()

def lsst.pex.config.configChoiceField.ConfigChoiceField.rename (   self,
  instance 
)
Rename the field in a `~lsst.pex.config.Config` (for internal use
only).

Parameters
----------
instance : `lsst.pex.config.Config`
    The config instance that contains this field.

Notes
-----
This method is invoked by the `lsst.pex.config.Config` object that
contains this field and should not be called directly.

Renaming is only relevant for `~lsst.pex.config.Field` instances that
hold subconfigs. `~lsst.pex.config.Fields` that hold subconfigs should
rename each subconfig with the full field name as generated by
`lsst.pex.config.config._joinNamePath`.

Reimplemented from lsst.pex.config.config.Field.

◆ save()

def lsst.pex.config.configChoiceField.ConfigChoiceField.save (   self,
  outfile,
  instance 
)
Save this field to a file (for internal use only).

Parameters
----------
outfile : file-like object
    A writeable field handle.
instance : `Config`
    The `Config` instance that contains this field.

Notes
-----
This method is invoked by the `~lsst.pex.config.Config` object that
contains this field and should not be called directly.

The output consists of the documentation string
(`lsst.pex.config.Field.doc`) formatted as a Python comment. The second
line is formatted as an assignment: ``{fullname}={value}``.

This output can be executed with Python.

Reimplemented from lsst.pex.config.config.Field.

◆ toDict()

def lsst.pex.config.configChoiceField.ConfigChoiceField.toDict (   self,
  instance 
)
Convert the field value so that it can be set as the value of an
item in a `dict` (for internal use only).

Parameters
----------
instance : `Config`
    The `Config` that contains this field.

Returns
-------
value : object
    The field's value. See *Notes*.

Notes
-----
This method invoked by the owning `~lsst.pex.config.Config` object and
should not be called directly.

Simple values are passed through. Complex data structures must be
manipulated. For example, a `~lsst.pex.config.Field` holding a
subconfig should, instead of the subconfig object, return a `dict`
where the keys are the field names in the subconfig, and the values are
the field values in the subconfig.

Reimplemented from lsst.pex.config.config.Field.

◆ validate()

def lsst.pex.config.configChoiceField.ConfigChoiceField.validate (   self,
  instance 
)
Validate the field (for internal use only).

Parameters
----------
instance : `lsst.pex.config.Config`
    The config instance that contains this field.

Raises
------
lsst.pex.config.FieldValidationError
    Raised if verification fails.

Notes
-----
This method provides basic validation:

- Ensures that the value is not `None` if the field is not optional.
- Ensures type correctness.
- Ensures that the user-provided ``check`` function is valid.

Most `~lsst.pex.config.Field` subclasses should call
`lsst.pex.config.field.Field.validate` if they re-implement
`~lsst.pex.config.field.Field.validate`.

Reimplemented from lsst.pex.config.config.Field.


The documentation for this class was generated from the following file: