Constraint

class jwst.associations.lib.constraint.Constraint(init=None, reduce=None, name=None, reprocess_on_match=False, reprocess_on_fail=False, work_over=ListCategory.BOTH, reprocess_rules=None)

Bases: object

Constraint that is made up of SimpleConstraints.

constraints

List of Constraint or SimpleConstraint that make this constraint.

Type:

[Constraint[,…]]

matched

Result of the last check_and_set

Type:

bool

reduce

A reduction function with signature x(iterable) where iterable is the components list. Returns boolean indicating state of the components. Predefined functions are: - all: True if all components return True - any: True if any component returns True

Type:

function

Notes

Named constraints can be accessed directly through indexing:

>>> c = Constraint(SimpleConstraint(name="simple", value="a_value"))
>>> c["simple"]
SimpleConstraint({'sources': <function SimpleConstraint.__init__.<locals>.<lambda>,
                  'force_unique': True,
                  'test': <bound method SimpleConstraint.eq of SimpleConstraint({...})>,
                  'reprocess_on_match': False,
                  'reprocess_on_fail': False,
                  'work_over': 1,
                  'reprocess_rules': None,
                  'value': 'a_value',
                  'name': 'simple',
                  'matched': False})

Initialize a new Constraint.

Parameters:

• init (object or [object[,...]]) – A single object or list of objects where the objects are as follows. - SimpleConstraint or subclass - Constraint

• reduce (function) – A reduction function with signature x(iterable) where iterable is the components list. Returns boolean indicating state of the components. Default value is Constraint.all

• name (str or None) – Optional name for constraint.

• reprocess_on_match (bool) – Reprocess the item if the constraint is satisfied.

• reprocess_on_fail (bool) – Reprocess the item if the constraint is not satisfied.

• work_over (ListCategory.[BOTH, EXISTING, RULES]) – The condition on which this constraint should operate.

• reprocess_rules ([rule[,..]] or None) – List of rules to be applied to. If None, calling function will determine the ruleset. If empty, [], all rules will be used.

Attributes Summary

dup_names	Return dictionary of constraints with duplicate names.
id	Return identifier for the constraint.

Methods Summary

all(item, constraints)	Return positive only if all results are positive.
any(item, constraints)	Return the first successful constraint.
append(constraint)	Append a new constraint.
check_and_set(item[, work_over])	Check and set the constraint.
copy()	Copy ourselves.
get_all_attr(attribute[, name])	Return the specified attribute for specified constraints.
notall(item, constraints)	Check if not all of the constraints match; true if not all do.
notany(item, constraints)	Check if none of the constraints match; true if none do.
preserve()	Preserve all constraint states.
restore()	Restore all constraint states.

Attributes Documentation

dup_names

Return dictionary of constraints with duplicate names.

This method is meant to be overridden by classes that need to traverse a list of constraints.

Returns:

dups – Returns a mapping between the duplicated name and all the constraints that define that name.

Return type:

{str: [constraint[,…]][,…]}

id

Return identifier for the constraint.

Returns:

id – The identifier

Return type:

str

Methods Documentation

static all(item, constraints)

Return positive only if all results are positive.

Parameters:

• item (ACID) – The candidate.

• constraints (list[Constraint, ...]) – The list of constraints to check.

Returns:

True if all constraints positive, with empty list. If no constraints, False and empty list. Otherwise False with list of constraints to reprocess.

Return type:

bool, list(Constraint, …) or None

static any(item, constraints)

Return the first successful constraint.

Parameters:

• item (ACID) – The candidate.

• constraints (list[Constraint, ...]) – The list of constraints to check.

Returns:

False, [] if no match or constraints to reprocess. True, list(Constraints) if match found, and any constraints to reprocess listed.

Return type:

bool, list(Constraint, …) or None

append(constraint)

Append a new constraint.

check_and_set(item, work_over=ListCategory.BOTH)

Check and set the constraint.

Returns:

success, reprocess –

Returns 2-tuple of

• success : True if check is successful.

• List of ProcessList.

Return type:

bool, [ProcessList[,…]]

copy()

Copy ourselves.

Returns:

Deepcopy of self.

Return type:

object

get_all_attr(attribute, name=None)

Return the specified attribute for specified constraints.

Parameters:

• attribute (str) – The attribute to retrieve

• name (str or None) – Only return attribute if the name of the current constraint matches the requested named constraints. If None, always return value.

Returns:

result – The list of values of the attribute in a tuple. If there is no attribute, an empty tuple is returned.

Return type:

[(SimpleConstraint or Constraint, object)[,…]]

Raises:

AttributeError – If the attribute is not found.

static notall(item, constraints)

Check if not all of the constraints match; true if not all do.

Parameters:

• item (ACID) – The candidate.

• constraints (list[Constraint, ...]) – The list of constraints to check.

Returns:

True if not all constraints match.

Return type:

bool

static notany(item, constraints)

Check if none of the constraints match; true if none do.

Parameters:

• item (ACID) – The candidate.

• constraints (list[Constraint, ...]) – The list of constraints to check.

Returns:

True if none of the constraints match.

Return type:

bool

preserve()

Preserve all constraint states.

restore()

Restore all constraint states.