def _construct_projection_context(
self,
proj_directive: 'ProjectionDirective',
attr_ctx: 'CdmAttributeContext',
ras: Optional['ResolvedAttributeSet'] = None
) -> 'ProjectionContext':
"""
A function to construct projection context and populate the resolved attribute set that ExtractResolvedAttributes method can then extract
This function is the entry point for projection resolution.
This function is expected to do the following 3 things:
- Create an condition expression tree & default if appropriate
- Create and initialize Projection Context
- Process operations
"""
if not attr_ctx:
return None
proj_context = None
# Add projection to context tree
acp_proj = AttributeContextParameters()
acp_proj._under = attr_ctx
acp_proj._type = CdmAttributeContextType.PROJECTION
acp_proj._name = self.fetch_object_definition_name()
acp_proj._regarding = proj_directive._owner_ref
acp_proj._include_traits = False
ac_proj = CdmAttributeContext._create_child_under(
proj_directive._res_opt, acp_proj)
acp_source = AttributeContextParameters()
acp_source._under = ac_proj
acp_source._type = CdmAttributeContextType.SOURCE
acp_source._name = 'source'
acp_source._regarding = None
acp_source._include_traits = False
ac_source = CdmAttributeContext._create_child_under(
proj_directive._res_opt, acp_source)
# Initialize the projection context
ctx = proj_directive._owner.ctx if proj_directive._owner else None
if self.source:
source = self.source.fetch_object_definition(
proj_directive._res_opt)
if source.object_type == CdmObjectType.PROJECTION_DEF:
# A Projection
proj_context = source._construct_projection_context(
proj_directive, ac_source, ras)
else:
# An Entity Reference
acp_source_projection = AttributeContextParameters()
acp_source_projection._under = ac_source
acp_source_projection._type = CdmAttributeContextType.ENTITY
acp_source_projection._name = self.source.named_reference if self.source.named_reference else self.source.explicit_reference.get_name(
)
acp_source_projection._regarding = self.source
acp_source_projection._include_traits = False
ras = self.source._fetch_resolved_attributes(
proj_directive._res_opt,
acp_source_projection) # type: ResolvedAttributeSet
# clean up the context tree, it was left in a bad state on purpose in this call
ras.attribute_context._finalize_attribute_context(
proj_directive._res_opt, ac_source.at_corpus_path,
self.in_document, self.in_document, None, False)
# if polymorphic keep original source as previous state
poly_source_set = None
if proj_directive._is_source_polymorphic:
poly_source_set = ProjectionResolutionCommonUtil._get_polymorphic_source_set(
proj_directive, ctx, self.source, ras)
# Now initialize projection attribute state
pas_set = ProjectionResolutionCommonUtil._initialize_projection_attribute_state_set(
proj_directive, ctx, ras,
proj_directive._is_source_polymorphic, poly_source_set)
proj_context = ProjectionContext(proj_directive,
ras.attribute_context)
proj_context._current_attribute_state_set = pas_set
else:
# A type attribute
# Initialize projection attribute state
pas_set = ProjectionResolutionCommonUtil._initialize_projection_attribute_state_set(
proj_directive,
ctx,
ras,
is_source_polymorphic=False,
polymorphic_set=None)
proj_context = ProjectionContext(proj_directive,
ras.attribute_context)
proj_context._current_attribute_state_set = pas_set
is_condition_valid = False
input_values = InputValues(proj_directive)
is_condition_valid = ExpressionTree._evaluate_condition(
self.condition, input_values)
if is_condition_valid and self.operations and len(self.operations) > 0:
# Just in case operations were added programmatically, reindex operations
for i in range(len(self.operations)):
self.operations[i]._index = i + 1
# Operation
acp_gen_attr_set = AttributeContextParameters()
acp_gen_attr_set._under = attr_ctx
acp_gen_attr_set._type = CdmAttributeContextType.GENERATED_SET
acp_gen_attr_set._name = '_generatedAttributeSet'
ac_gen_attr_set = CdmAttributeContext._create_child_under(
proj_directive._res_opt, acp_gen_attr_set)
# Start with an empty list for each projection
pas_operations = ProjectionAttributeStateSet(
proj_context._current_attribute_state_set._ctx)
# The attribute set that the operation will execute on
operation_working_attribute_set = None # type: ProjectionAttributeStateSet
# The attribute set containing the attributes from the source
source_attribute_set = proj_context._current_attribute_state_set # type: ProjectionAttributeStateSet
# Specifies if the operation is the first on the list to run
first_operation_to_run = True
for operation in self.operations:
operation_condition = ExpressionTree._evaluate_condition(
operation.condition, input_values)
if not operation_condition:
# Skip this operation if the condition does not evaluate to true
continue
# If run_sequentially is not true then all the operations will receive the source input
# Unless the operation overwrites this behavior using the source_input property
source_input = operation.source_input if operation.source_input is not None else not self.run_sequentially
# If this is the first operation to run it will get the source attribute set since the operations attribute set starts empty
if source_input or first_operation_to_run:
proj_context._current_attribute_state_set = source_attribute_set
operation_working_attribute_set = pas_operations
else:
# Needs to create a copy since this set can be modified by the operation
proj_context._current_attribute_state_set = pas_operations._copy(
)
operation_working_attribute_set = ProjectionAttributeStateSet(
proj_context._current_attribute_state_set._ctx)
# Evaluate projections and apply to empty state
new_pas_operations = operation._append_projection_attribute_state(
proj_context, operation_working_attribute_set,
ac_gen_attr_set)
# If the operations fails or it is not implemented the projection cannot be evaluated so keep previous valid state.
if new_pas_operations is not None:
first_operation_to_run = False
pas_operations = new_pas_operations
# If no operation ran successfully pas_operations will be empty
if not first_operation_to_run:
# Finally update the current state to the projection context
proj_context._current_attribute_state_set = pas_operations
return proj_context
def _construct_projection_context(self, proj_directive: 'ProjectionDirective', attr_ctx: 'CdmAttributeContext', ras: Optional['ResolvedAttributeSet'] = None) -> 'ProjectionContext':
"""
A function to construct projection context and populate the resolved attribute set that ExtractResolvedAttributes method can then extract
This function is the entry point for projection resolution.
This function is expected to do the following 3 things:
- Create an condition expression tree & default if appropriate
- Create and initialize Projection Context
- Process operations
"""
proj_context = None
condition = self.condition if self.condition else "(true)"
# create an expression tree based on the condition
tree = ExpressionTree()
self._condition_expression_tree_root = tree._construct_expression_tree(condition)
if attr_ctx:
# Add projection to context tree
acp_proj = AttributeContextParameters()
acp_proj._under = attr_ctx
acp_proj._type = CdmAttributeContextType.PROJECTION
acp_proj._name = self.fetch_object_definition_name()
acp_proj._regarding = proj_directive._owner_ref
acp_proj._include_traits = False
ac_proj = CdmAttributeContext._create_child_under(proj_directive._res_opt, acp_proj)
acp_source = AttributeContextParameters()
acp_source._under = ac_proj
acp_source._type = CdmAttributeContextType.SOURCE
acp_source._name = 'source'
acp_source._regarding = None
acp_source._include_traits = False
ac_source = CdmAttributeContext._create_child_under(proj_directive._res_opt, acp_source)
# Initialize the projection context
ctx = proj_directive._owner.ctx if proj_directive._owner else None
if self.source:
source = self.source.fetch_object_definition(proj_directive._res_opt)
if source.object_type == CdmObjectType.PROJECTION_DEF:
# A Projection
proj_context = self.source.explicit_reference._construct_projection_context(proj_directive, ac_source, ras)
else:
# An Entity Reference
acp_source_projection = AttributeContextParameters()
acp_source_projection._under = ac_source
acp_source_projection._type = CdmAttributeContextType.ENTITY
acp_source_projection._name = self.source.named_reference if self.source.named_reference else self.source.explicit_reference.get_name()
acp_source_projection._regarding = self.source
acp_source_projection._include_traits = False
ras = self.source._fetch_resolved_attributes(proj_directive._res_opt, acp_source_projection)
# If polymorphic keep original source as previous state
poly_source_set = None
if proj_directive._is_source_polymorphic:
poly_source_set = ProjectionResolutionCommonUtil._get_polymorphic_source_set(proj_directive, ctx, self.source, acp_source_projection)
# Now initialize projection attribute state
pas_set = ProjectionResolutionCommonUtil._initialize_projection_attribute_state_set(
proj_directive,
ctx,
ras,
proj_directive._is_source_polymorphic,
poly_source_set
)
proj_context = ProjectionContext(proj_directive, ras.attribute_context)
proj_context._current_attribute_state_set = pas_set
else:
# A type attribute
# Initialize projection attribute state
pas_set = ProjectionResolutionCommonUtil._initialize_projection_attribute_state_set(
proj_directive,
ctx,
ras,
is_source_polymorphic=False,
polymorphic_set=None
)
proj_context = ProjectionContext(proj_directive, ras.attribute_context)
proj_context._current_attribute_state_set = pas_set
is_condition_valid = False
if self._condition_expression_tree_root:
input = InputValues()
input.no_max_depth = proj_directive._has_no_maximum_depth
input.is_array = proj_directive._is_array
input.reference_only = proj_directive._is_reference_only
input.normalized = proj_directive._is_normalized
input.structured = proj_directive._is_structured
input.is_virtual = proj_directive._is_virtual
current_depth = proj_directive._current_depth
current_depth += 1
input.next_depth = current_depth
proj_directive._current_depth = current_depth
input.max_depth = proj_directive._maximum_depth
input.min_cardinality = proj_directive._cardinality._minimum_number if proj_directive._cardinality else None
input.max_cardinality = proj_directive._cardinality._maximum_number if proj_directive._cardinality else None
is_condition_valid = ExpressionTree._evaluate_expression_tree(self._condition_expression_tree_root, input)
if is_condition_valid and self.operations and len(self.operations) > 0:
# Just in case operations were added programmatically, reindex operations
for i in range(len(self.operations)):
self.operations[i]._index = i + 1
# Operation
acp_gen_attr_set = AttributeContextParameters()
acp_gen_attr_set._under = attr_ctx
acp_gen_attr_set._type = CdmAttributeContextType.GENERATED_SET
acp_gen_attr_set._name = '_generatedAttributeSet'
ac_gen_attr_set = CdmAttributeContext._create_child_under(proj_directive._res_opt, acp_gen_attr_set)
# Start with an empty list for each projection
pas_operations = ProjectionAttributeStateSet(proj_context._current_attribute_state_set._ctx)
for operation in self.operations:
# Evaluate projections and apply to empty state
new_pas_operations = operation._append_projection_attribute_state(proj_context, pas_operations, ac_gen_attr_set)
# If the operations fails or it is not implemented the projection cannot be evaluated so keep previous valid state.
if new_pas_operations is not None:
pas_operations = new_pas_operations
# Finally update the current state to the projection context
proj_context._current_attribute_state_set = pas_operations
return proj_context