architectural-refactorings

Architectural Refactoring (AR) Examples

This folder contains input and ouput examples written in CML to illustrate the idea behind the Architectural Refactorings (ARs) implemented by the Context Mapper tool. The refactorings can be executed with a right-click on the corresponding element in the editor (aggregate, bounded context, or relationship arrows) and choosing the AR in the Context Mapper: Refactor context menu entry. The context menu shows only refactorings for which the selected model element fulfills the preconditions.

You find an overview table with all ARs below. Within the sub-folders of this directory you find detailed descriptions and the code samples for each AR:

• AR-1: Split Aggregate by Entities
• AR-2: Split Bounded Context by Features
• AR-3: Split Bounded Context by Owner
• AR-4: Extract Aggregates by Volatility
• AR-5: Extract Aggregates by Cohesion
• AR-6: Merge Aggregates
• AR-7: Merge Bounded Contexts
• AR-8: Extract Shared Kernel
• AR-9: Suspend Partnership
• AR-10: Change Shared Kernel to Partnership
• AR-11: Change Partnership to Shared Kernel

You can also find the ARs in our documentation page.

Motivation to use ARs

The provided refactorings offer the advantage that the result is always a correct CML model which compiles without errors. If you perform similar changes manually, you also have to fix upcoming errors within the context map manually. The AR's ensure that corresponding references and dependencies in other parts of the model are respected and adjusted if necessary.

AR Categories

The ARs are divided into the following categories:

• Structural Refactorings: Change the structure of the decomposition (impact on Bounded Contexts and/or Aggregates).
• Relationship Refactorings: Just change the type of a relationship on the Context Map, but do not change the structure of the decomposition.

Structural AR Overview

Name	Subject	Description	Input	Output
AR-1: Split Aggregate by Entities	Aggregate	Splits an aggregate which contains multiple entities and produces one aggregate per entity.	1 Aggregate	n Aggregates
AR-2: Split Bounded Context by Features1	Bounded Context	Splits a bounded context by grouping those aggregates together into one bounded context which are used by the same use case(s) and/or user stories.	1 Bounded Context	n Bounded Contexts
AR-3: Split Bounded Context by Owner1	Bounded Context	Splits a bounded context by grouping those aggregates together into one bounded context which belong to the same team.	1 Bounded Context	n Bounded Contexts
AR-4: Extract Aggregates by Volatility	Bounded Context	Extracts all aggregates from a bounded context by a given volatility, or likelihood for change (RARELY, NORMAL or OFTEN), and moves them to a separate context.	1 Bounded Context	2 Bounded Contexts
AR-5: Extract Aggregates by Cohesion	Bounded Context	Extracts a set of aggregates which are chosen by certain cohesion criteria and moves them to a separate bounded context.	1 Bounded Context	2 Bounded Contexts
AR-6: Merge Aggregates	Aggregate	Merges two aggregates within a bounded context together to one aggregate.	2 Aggregates	1 Aggregate
AR-7: Merge Bounded Contexts	Bounded Context	Merges two bounded contexts together. The result is one bounded context containing all the aggregates of the two input boundedcontexts.	2 Bounded Contexts	1 Bounded Context
AR-8: Extract Shared Kernel	Shared Kernel relationship	Extracts a new bounded context for the common model parts of the Shared Kernel and establishes two upstream-downstream relationship between the new and the existing Bounded Contexts.	1 Shared Kernel relationship	1 New Bounded Context and 2 new upstream-downstream relationships
AR-9: Suspend Partnership	Partnership relationship	Suspends a Partnership relationship and replaces it with another structure how the two Bounded Context can depend on each other. The AR provides three strategies to suspend the partnership.	1 Partnership relationship	Depends on the selected mode

¹: An aggregate in CML can be used by multiple use cases and is owned by one owner (team).

Relationship AR Overview

Name	Subject	Description	Input	Output
AR-10: Change Shared Kernel to Partnership	Shared Kernel relationship	Changes the type of a Shared Kernel relationship to a Partnership relationship.	Shared Kernel relationship	Partnership relationship
AR-11: Change Partnership to Shared Kernel	Partnership relationship	Changes the type of a Partnership relationship to a Shared Kernel relationship.	Partnership relationship	Shared Kernel relationship

Hints

• Split vs. Extract:

  • The ARs which split the subject create n new elements of the type of the subject, one for each child element by which the AR splits. For example: Split Bounded Context by Owner creates n new bounded contexts, one for each aggregate owner (team).
  • The ARs which extract in comparison, create only one new element of the subjects type. An extraction moves a set of child elements to the newly created element of the subjects type. For example: Extract Aggregates by Volatility creates one new bounded context and moves a specific set of aggregates to this new bounded context.

• Note (Formatting): The execution of a refactoring in a CML file always formats the model according to our predefined formatting. You can format your models manually by using the Eclipse formatting shortcut (SHIFT-CTRL-F by default). If your file is not formatted or contains user-specific formattings, the execution of a refactoring will change the formatting accordingly.

• Note (Root Element Order): The execution of a refactoring in a CML file always unparses the complete model by using the following order of elements on the root level:

  1. Context Map
  2. Bounded Contexts
  3. Domains
  4. Use Cases

  If the elements in your CML file are not ordered correspondingly, the execution of a refactoring will reorder them.