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

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.

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> at 0x7f8be05f5730>,
                  '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})

Attributes Summary

dup_names	Return dictionary of constraints with duplicate names
id	Return identifyer 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)	Return the specified attribute
notall(item, constraints)	True if not all of the constraints match
notany(item, constraints)	True if none of the constraints match

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 identifyer for the constraint

Returns:

id – The identifyer

Return type:

str

Methods Documentation

static all(item, constraints)

Return positive only if all results are positive.

static any(item, constraints)

Return the first successful constraint.

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

get_all_attr(attribute: str)

Return the specified attribute

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

Parameters:

attribute (str) – The attribute to retrieve

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)

True if not all of the constraints match

static notany(item, constraints)

True if none of the constraints match