docs: update composite entity

This commit is contained in:
Ilkka Seppälä
2024-05-24 20:53:29 +03:00
parent 1029c02993
commit 518ffa4d4d
+21 -9
View File
@@ -5,7 +5,11 @@ language: en
tag:
- Client-server
- Data access
- Decoupling
- Enterprise patterns
- Object composition
- Persistence
- Resource management
---
## Also known as
@@ -20,14 +24,20 @@ The Composite Entity design pattern is aimed at managing a set of interrelated p
Real world example
> For a console, there may be many interfaces that need to be managed and controlled. Using the composite entity pattern, dependent objects such as messages and signals can be combined and controlled using a single object.
> Consider a university registration system where a "Student" entity is a composite entity. Each "Student" object includes several dependent objects: personal details, course enrollments, grades, and payment information. Instead of managing each of these aspects separately, the Composite Entity pattern allows the university system to treat the "Student" as a single entity. This simplifies operations such as enrolling a student in a new course, updating grades, and processing payments, since all related actions can be managed through the composite "Student" object.
In plain words
> Composite entity pattern allows a set of related objects to be represented and managed by a unified object.
Wikipedia says
> Composite entity is a Java EE Software design pattern and it is used to model, represent, and manage a set of interrelated persistent objects rather than representing them as individual fine-grained entity beans, and also a composite entity bean represents a graph of objects.
**Programmatic Example**
For a console, there may be many interfaces that need to be managed and controlled. Using the composite entity pattern, dependent objects such as messages and signals can be combined and controlled using a single object.
We need a generic solution for the problem. To achieve this, let's introduce a generic Composite Entity Pattern.
```java
@@ -103,17 +113,19 @@ public class CompositeEntity {
Now managing the assignment of message and signal objects with the composite entity `console`.
```java
var console=new CompositeEntity();
console.init();
console.setData("No Danger","Green Light");
Arrays.stream(console.getData()).forEach(LOGGER::info);
console.setData("Danger","Red Light");
Arrays.stream(console.getData()).forEach(LOGGER::info);
public App(String message, String signal) {
var console = new CompositeEntity();
console.init();
console.setData(message, signal);
Arrays.stream(console.getData()).forEach(LOGGER::info);
console.setData("Danger", "Red Light");
Arrays.stream(console.getData()).forEach(LOGGER::info);
}
```
## Class diagram
![alt text](./etc/composite_entity.urm.png "Composite Entity Pattern")
![Composite Entity](./etc/composite_entity.urm.png "Composite Entity")
## Applicability
@@ -149,7 +161,7 @@ Trade-offs:
## Credits
* [Composite Entity Pattern in wikipedia](https://en.wikipedia.org/wiki/Composite_entity_pattern)
* [Core J2EE Patterns: Best Practices and Design Strategies](https://amzn.to/4cAbDap)
* [Enterprise Patterns and MDA: Building Better Software with Archetype Patterns and UML](https://amzn.to/49mslqS)
* [Patterns of Enterprise Application Architecture](https://amzn.to/3xjKdpe)
* [Composite Entity Pattern (Wikipedia)](https://en.wikipedia.org/wiki/Composite_entity_pattern)