JSON Import Labs

This example illustrated importing SysML v2 model from a JSON file by deserializing it. The main function of interest is json.loads, which takes a JSON array s and a document of class Document that the deserialized model will be stored in. The json.loads function returns the deserialized model which can then be used as if it was imported from a .sysml file.

Concepts Used

• A Model is a SysMLv2 model represented using abstract syntax. This is the output of the function load_model.

• The syside.json module for serializing to SysML v2 JSON.

• walk_ownership_tree is a function that prints out elements in a model in a tree-like format. In this example it is used to show that the model has been successfully deserialized from JSON format.

Example Script

import pathlib
import syside

EXAMPLE_DIR = pathlib.Path(__file__).parent
MODEL_FILE_PATH = EXAMPLE_DIR / "example_model_3.sysml"
# The deserialized model will be stored in a document with MODEL_PATH path.
# The MODEL_PATH does not necessarily need to exist on the local file system.
MODEL_PATH = "file://" + str(MODEL_FILE_PATH)


def walk_ownership_tree(element: syside.Element, level: int = 0) -> None:
    """
    Prints out all elements in a model in a tree-like format, where
    child elements appear indented under their parent elements. For
    example:

    Parent
      Child1
      Child2
        Grandchild

    Args:
        element: The model element to start printing from
        level: How many levels to indent (increases for nested elements)
    """
    if element.name is not None:
        print("  " * level, element.name)
    else:
        print("  " * level, "anonymous element")
    # Recursively call walk_ownership_tree() for each owned element
    # (child element).
    element.owned_elements.for_each(
        lambda owned_element: walk_ownership_tree(owned_element, level + 1)
    )


def main() -> None:
    with open("example_json.json", "r") as f:
        json_import = f.read()
    deserialized_model, _ = syside.json.loads(json_import, MODEL_PATH)

    walk_ownership_tree(deserialized_model.document.root_node)


if __name__ == "__main__":
    main()

Output

anonymous element
  JSON Export Example
    Electrical
    Mechanical
    Automobile
      Drive Train
      Chassis

Download

Download this example here.