聚合和聚合根是否作为单独的 类 实现？
Are aggregates and aggregate roots implemented as separate classes?
关于 DDD 的讨论如此之多，我希望找到大量代码示例如何实现这些模式。但就没那么幸运了。
让我困惑的是这个。是一种聚合实体，表示为聚合根，还是作为单独的 classes 实现的实体？以下是几个例子，请回答是否正确。
- 它们是分开的 classes
class Aggregate {
private Entity aggregateRootEntity;
//methods that keep invariants
}
- 没有单独的聚合class，而是聚合根class，代表聚合
class AggregateRootEntity {
//id, fields, value objects references, other entities references
//methods that keep invariants
}
- 任何实体都可以是聚合，如果它在事务范围内使用，保持不变量，并“聚合”一些值对象
//This is aggregate:
class Entity {
private List<ValueObject> valueObjects;
//id, fields
//methods that keep invariants
}
There is no separate aggregate class, but aggregate root class, which represents the aggregate
这个。
介绍 DDD 和“聚合”模式的参考书是 Eric Evans Domain Driven Design: Tackling Complexity int the Heart of Software。
第 5 章讨论了在软件领域建模中使用的模式：实体、值、“领域服务”等。
第 6 章讨论了生命周期管理，其中他谈到了工厂、存储库和聚合：
An AGGREGATE is a cluster of of associated objects we treat as a unit for the purpose of data changes. Each aggregate has a root and a boundary. The boundary defines what is inside the aggregate. The root is a single, specific ENTITY contained in the aggregate. The root is the only member of the AGGREGATE that outside objects are allowed to hold references to....
如果您愿意，聚合是对象的 图 ，其中包括根对象，以及您可以通过遍历本地引用从根对象到达的其他对象。
关于 DDD 的讨论如此之多，我希望找到大量代码示例如何实现这些模式。但就没那么幸运了。
让我困惑的是这个。是一种聚合实体，表示为聚合根，还是作为单独的 classes 实现的实体？以下是几个例子，请回答是否正确。
- 它们是分开的 classes
class Aggregate {
private Entity aggregateRootEntity;
//methods that keep invariants
}
- 没有单独的聚合class，而是聚合根class，代表聚合
class AggregateRootEntity {
//id, fields, value objects references, other entities references
//methods that keep invariants
}
- 任何实体都可以是聚合，如果它在事务范围内使用，保持不变量，并“聚合”一些值对象
//This is aggregate:
class Entity {
private List<ValueObject> valueObjects;
//id, fields
//methods that keep invariants
}
There is no separate aggregate class, but aggregate root class, which represents the aggregate
这个。
介绍 DDD 和“聚合”模式的参考书是 Eric Evans Domain Driven Design: Tackling Complexity int the Heart of Software。
第 5 章讨论了在软件领域建模中使用的模式：实体、值、“领域服务”等。
第 6 章讨论了生命周期管理，其中他谈到了工厂、存储库和聚合：
An AGGREGATE is a cluster of of associated objects we treat as a unit for the purpose of data changes. Each aggregate has a root and a boundary. The boundary defines what is inside the aggregate. The root is a single, specific ENTITY contained in the aggregate. The root is the only member of the AGGREGATE that outside objects are allowed to hold references to....
如果您愿意，聚合是对象的 图 ，其中包括根对象，以及您可以通过遍历本地引用从根对象到达的其他对象。