Class: Archimate::DataModel::Insert

Inherits:
Struct
  • Object
show all
Defined in:
lib/archimate/data_model/differentiable.rb

Overview

Let’s talk about diff…

Here are my expectations of diff:

Preconditions:

  1. self is non-nil

  2. self is a class that includes Comparison

Requirements for other

Not matching one of these is a programming error.

  1. Other is nil

  2. Other is an instance of the same class as self

Diff results

  • Diffing results in a list of Diff instances between self and other

  • Patching the list of diffs against self results in an instance that == other

Diff Container

A diff container is a top level entity that is meaningful in the user domain for example: [Element], [Relationship], [Diagram]. It collects and groups the smaller diffs into the things that changed by an entity tha makes sense to the user.

Diff structure

A diff contains a change to be applied in a particular context.

Use cases:

  1. Delete a value that is a member of this class. Example: Delete the a member of a [Color] instance.

  2. A non-reference value replacing a value in a class. Example: Changing the r value of a [Color] with a different value.

  3. Updating the value of an attribute of a child. (or child’s child)

  4. Deleting the value of an attribute of a child. (or child’s child)

  5. For Array attributes with non-referenceable contents

    1. Deleting a value from an array attribute

    2. Inserting a value into an array attribute

    3. Changing a value in an array attribute

  6. For Array attributes with referenceable contents

    1. Deleting a value from an array attribute (has an implication on if the entity is deleted from the model entirely)

    2. Inserting a value into an array attribute (may need addtion to the model)

    3. Changing a value in an array attribute (changing the entity id may require the implications of deletion and insertion as above)

When to stop?

When digging down into a diff operation, there are some natural stopping points:

  1. When there is no more depth to dig

  2. When the objects being compared are references to other entities, but do not belong to the current object being diffed.

  3. When the object being diffed is a Diff container unto itself. For example: When diffing a model, the diff should include the order of elements referenced in the elements attribute, but shouldn’t continue with the diff of each element itself.

Complications

Object references

Since a patch operation produces an new replacement object, object references need to be handled. For example, given an Element with id=3 if a patch changes this Element‘s name, then the Element in the model under Model#elements is replaced with a different instance, but a Relationship that references the Element is still pointing at a different instance and needs to be updated.

Instance Attribute Summary collapse

Instance Attribute Details

#path ⇒ Object

Returns the value of attribute path

Returns:

  • (Object) —

    the current value of path



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# File 'lib/archimate/data_model/differentiable.rb', line 80

def path
  @path
end

#value ⇒ Object

Returns the value of attribute value

Returns:

  • (Object) —

    the current value of value



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# File 'lib/archimate/data_model/differentiable.rb', line 80

def value
  @value
end