Add object diagrams service

services/od.py

@@ -0,0 +1,86 @@
+from uuid import UUID
+from state.base import State
+from services.bottom.V0 import Bottom
+from services.primitives.integer_type import Integer
+from services.primitives.string_type import String
+
+# Object Diagrams service
+
+class OD:
+
+    def __init__(self, type_model: UUID, model: UUID, state: State):
+        """
+        Implements services for the object diagrams LTM.
+        Implementation is done in terms of services provided by LTM-bottom.
+
+            Args:
+                type_model: The SCD-conforming class diagram that contains the types of this object diagram
+                model: UUID of the (OD) model to manipulate
+        """
+
+        self.type_model = type_model
+        self.model = model
+        self.bottom = Bottom(state)
+
+
+    def create_object(self, name: str, class_name: str):
+        class_node, = self.bottom.read_outgoing_elements(self.type_model, class_name)
+
+
+        abstract_nodes = self.bottom.read_outgoing_elements(self.type_model, f"{class_name}.abstract")
+        if len(abstract_nodes) == 1:
+            is_abstract = self.bottom.read_value(abstract_node)
+        else:
+            # 'abstract' is optional attribute, default is False
+            is_abstract = False
+
+        print("class", name, "is abstract?", is_abstract)
+
+        if is_abstract:
+            raise Exception("Cannot instantiate abstract class!")
+
+        object_node = self.bottom.create_node()
+        self.bottom.create_edge(self.model, object_node, name) # attach to model
+        self.bottom.create_edge(object_node, class_node, "Morphism") # typed-by link
+
+        return object_node
+
+
+    def create_slot(self, object_name: str, attr_name: str, value: UUID):
+        attr_node = self.bottom.read_outgoing_elements(self.type_model, attr_name) # get the attribute
+        object_node, = self.bottom.read_outgoing_elements(self.model, object_name) # get the object
+        slot_node = value
+
+        # generate a unique name for the slot
+        i = 0;
+        while len(self.bottom.read_outgoing_elements(self.model, f"{object_name}.{attr_name}{i}")) != 0:
+            i += 1
+
+        self.bottom.create_edge(self.model, slot_node, f"{object_name}.{attr_name}{i}") # attach to model root
+        slot_link = self.bottom.create_edge(object_node, slot_node) # attach to object
+        self.bottom.create_edge(self.model, slot_link, f"{object_name}.{attr_name}{i}_link") # attach attr-link to model
+
+        self.bottom.create_edge(slot_node, attr_node, "Morphism") # slot typed-by attribute
+        slot_link_type, = self.bottom.read_outgoing_elements(self.type_model, "AttributeLink")
+        self.bottom.create_edge(slot_link, slot_link_type)
+
+
+    def create_link(self, assoc_name: str, src_obj_name: str, tgt_obj_name: str):
+        src_obj_node, = self.bottom.read_outgoing_elements(self.model, src_obj_name)
+        tgt_obj_node, = self.bottom.read_outgoing_elements(self.model, tgt_obj_name)
+
+        link_edge = self.bottom.create_edge(src_obj_node, tgt_obj_node);
+
+        # generate a unique name for the link
+        i = 0;
+        while True:
+            link_name = f"{assoc_name}{i}"
+            if len(self.bottom.read_outgoing_elements(self.model, link_name)) == 0:
+                break
+            i += 1
+
+        self.bottom.create_edge(self.model, link_edge, link_name)
+
+        type_edge, = self.bottom.read_outgoing_elements(self.type_model, assoc_name)
+        self.bottom.create_edge(link_edge, type_edge, "Morphism")
+