有状态命令模式
我想知道在域模型上下文中表示编辑表单的最佳方式是什么，最终我选择了命令设计模式。
据此：使用命令设计模式 命令应该是不可变的，这不是我所需要的 - 我需要具有可编辑参数的有状态命令（整个命令将在 ui/form 中编辑）
为什么认为有状态命令是不好的？
< strong>编辑：一段时间后，现在很清楚我正在寻找 ViewModel 模式。这是对任何 Web 应用程序屏幕进行建模的适当方法。基本上它是有状态的（每个视图实例）控制器。
I was wondering what is the best way to represent an edit form in the context of domain model and I ended up with the command design pattern.
According to this: Using Command Design pattern
commands should be immutable which is not what I need - I need stateful command with editable parameters (the whole command will be edited in ui/form)
Why is it considered to be bad to have stateful command?
EDIT: After some time it is now clear I was looking for the ViewModel pattern. That is the appropriate way to model any webapp screen. Basically it is stateful (per view instance) controller.
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您仍然希望它们是不可变的，因为它们可以用于从快照重新创建当前状态。但它们可以拥有您想要的所有参数，只要您确保它们在应用命令后不会更改即可。
You still want them to be immutable, because they can then be used to recreate the current state from a snapshot. But they can have all the parameters you want, as long as you make sure they cannot change after applying the command.
如果你希望它可变，我建议使用 FlyWeight 模式。您可以使其类似于命令模式，因为它是对象的散列，并且它会重用相同的对象（如果它们已经存在），从而保留对象状态。
您可以将 FlyWeight 视为一组可以动态调用的单例对象（通过哈希函数）。
因此，flyweightfactory 会将所有对象存储在哈希映射中，并且您可以使用该工厂来检索维护其状态的对象。
http://www.avajava.com/tutorials/lessons/flyweight-pattern.html -->供任何人参考。
if you want it mutable i would suggest using a FlyWeight Pattern instead. You can make it similar to a command pattern since its a hash of objects and it reuses the same objects if they exist already thus persisting the objects state.
You can think of FlyWeight as a group of singleton objects you can call on the fly (by a hash function).
So a flyweightfactory would house all your objects in a hash map and you could use the factory to retrieve the object maintaining its state.
http://www.avajava.com/tutorials/lessons/flyweight-pattern.html --> for anyone's reference.