pex.config.configChoiceField.ConfigChoiceField Class Reference

Inheritance diagram for pex.config.configChoiceField.ConfigChoiceField:

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)
def	__get__ (self, instance, owner=None, at=None, label="default")
def	__delete__ (self, instance, at=None, label='deletion')

Public Attributes
	typemap
	multi
	dtype
	doc
	deprecated
	default
	check
	optional
	source

Static Public Attributes
	instanceDictClass = ConfigInstanceDict
	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

Definition at line 324 of file configChoiceField.py.

Constructor & Destructor Documentation

__init__()

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

Reimplemented from pex.config.config.Field.

Definition at line 431 of file configChoiceField.py.

    def __init__(self, doc, typemap, default=None, optional=False, multi=False, deprecated=None):
        source = getStackFrame()
        self._setup(doc=doc, dtype=self.instanceDictClass, default=default, check=None, optional=optional,
                    source=source, deprecated=deprecated)
        self.typemap = typemap
        self.multi = multi
 

Member Function Documentation

__deepcopy__()

def 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 pex.config.registry.RegistryField.

Definition at line 525 of file configChoiceField.py.

    def __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!
        """
        other = type(self)(doc=self.doc, typemap=self.typemap, default=copy.deepcopy(self.default),
                           optional=self.optional, multi=self.multi)
        other.source = self.source
        return other
 

__delete__()

def pex.config.config.Field.__delete__ (   self,   instance,   at = None,   label = 'deletion'  )

inherited

Delete an attribute from a `lsst.pex.config.Config` instance.

Parameters
----------
instance : `lsst.pex.config.Config`
    The config instance that contains 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 is invoked by the owning `~lsst.pex.config.Config` object and
should not be called directly.

Definition at line 573 of file config.py.

    def __delete__(self, instance, at=None, label='deletion'):
        """Delete an attribute from a `lsst.pex.config.Config` instance.
 
        Parameters
        ----------
        instance : `lsst.pex.config.Config`
            The config instance that contains 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 is invoked by the owning `~lsst.pex.config.Config` object and
        should not be called directly.
        """
        if at is None:
            at = getCallStack()
        self.__set__(instance, None, at=at, label=label)
 

__get__() [1/2]

def pex.config.configChoiceField.ConfigChoiceField.__get__	(		self,
			instance,
			owner = None
	)

Definition at line 450 of file configChoiceField.py.

    def __get__(self, instance, owner=None):
        if instance is None or not isinstance(instance, Config):
            return self
        else:
            return self._getOrMake(instance)
 

__get__() [2/2]

def pex.config.config.Field.__get__ (   self,   instance,   owner = None,   at = None,   label = "default"  )

inherited

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 in pex.config.configurableField.ConfigurableField.

Definition at line 498 of file config.py.

    def __get__(self, instance, owner=None, at=None, label="default"):
        """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.
        """
        if instance is None or not isinstance(instance, Config):
            return self
        else:
            return instance._storage[self.name]
 

__set__()

def 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 pex.config.config.Field.

Definition at line 456 of file configChoiceField.py.

    def __set__(self, instance, value, at=None, label="assignment"):
        if instance._frozen:
            raise FieldValidationError(self, instance, "Cannot modify a frozen Config")
        if at is None:
            at = getCallStack()
        instanceDict = self._getOrMake(instance)
        if isinstance(value, self.instanceDictClass):
            for k, v in value.items():
                instanceDict.__setitem__(k, v, at=at, label=label)
            instanceDict._setSelection(value._selection, at=at, label=label)
 
        else:
            instanceDict._setSelection(value, at=at, label=label)
 

freeze()

def 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 pex.config.config.Field.

Definition at line 503 of file configChoiceField.py.

    def freeze(self, instance):
        instanceDict = self.__get__(instance)
        instanceDict.freeze()
        for v in instanceDict.values():
            v.freeze()
 

rename()

def 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 pex.config.config.Field.

Definition at line 470 of file configChoiceField.py.

    def rename(self, instance):
        instanceDict = self.__get__(instance)
        fullname = _joinNamePath(instance._name, self.name)
        instanceDict._rename(fullname)
 

save()

def 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 pex.config.config.Field.

Definition at line 515 of file configChoiceField.py.

    def save(self, outfile, instance):
        instanceDict = self.__get__(instance)
        fullname = _joinNamePath(instance._name, self.name)
        for v in instanceDict.values():
            v._save(outfile)
        if self.multi:
            outfile.write(u"{}.names={!r}\n".format(fullname, instanceDict.names))
        else:
            outfile.write(u"{}.name={!r}\n".format(fullname, instanceDict.name))
 

toDict()

def 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 pex.config.config.Field.

Definition at line 487 of file configChoiceField.py.

    def toDict(self, instance):
        instanceDict = self.__get__(instance)
 
        dict_ = {}
        if self.multi:
            dict_["names"] = instanceDict.names
        else:
            dict_["name"] = instanceDict.name
 
        values = {}
        for k, v in instanceDict.items():
            values[k] = v.toDict()
        dict_["values"] = values
 
        return dict_
 

validate()

def 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 pex.config.config.Field.

Definition at line 475 of file configChoiceField.py.

    def validate(self, instance):
        instanceDict = self.__get__(instance)
        if instanceDict.active is None and not self.optional:
            msg = "Required field cannot be None"
            raise FieldValidationError(self, instance, msg)
        elif instanceDict.active is not None:
            if self.multi:
                for a in instanceDict.active:
                    a.validate()
            else:
                instanceDict.active.validate()
 

Member Data Documentation

check

pex.config.config.Field.check

inherited

Definition at line 311 of file config.py.

default

pex.config.config.Field.default

inherited

Definition at line 307 of file config.py.

deprecated

pex.config.config.Field.deprecated

inherited

Definition at line 298 of file config.py.

doc

pex.config.config.Field.doc

inherited

Definition at line 294 of file config.py.

dtype

pex.config.config.Field.dtype

inherited

Definition at line 287 of file config.py.

instanceDictClass

pex.config.configChoiceField.ConfigChoiceField.instanceDictClass = ConfigInstanceDict

static

Definition at line 429 of file configChoiceField.py.

multi

pex.config.configChoiceField.ConfigChoiceField.multi

Definition at line 436 of file configChoiceField.py.

optional

pex.config.config.Field.optional

inherited

Definition at line 315 of file config.py.

source

pex.config.config.Field.source

inherited

Definition at line 322 of file config.py.

supportedTypes

pex.config.config.Field.supportedTypes = set((str, bool, float, int, complex))

staticinherited

Definition at line 272 of file config.py.

typemap

pex.config.configChoiceField.ConfigChoiceField.typemap

Definition at line 435 of file configChoiceField.py.

---

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

• /j/snowflake/release/lsstsw/stack/cb4e2dc/Linux64/pex_config/20.0.0+34a42eae2c/python/lsst/pex/config/configChoiceField.py