Java 23 design modes

Java 23 design modes

1. Factory model: the customer class and the factory class are separated. A consumer needs a product at any time and only requests from the factory. Consumers can accept new products without modification. The disadvantage is that the factory class must be modified when the product is modified. For example, how to create and provide data to clients.

 

2. Construction mode: separates the internal appearance of a product from the product generation process, so that a building process generates product objects with different internal appearances. The construction mode allows the product's internal appearance to change independently, so that the customer does not have to know the details of the product's internal composition. The construction model enforces a step-by-step construction process.

 

3. Factory method mode: the Core factory category is no longer responsible for the creation of all products. Instead, it submits the specific creation work to the subclass to become an abstract factory role, it is only responsible for providing the interface that must be implemented by a specific factory class, without touching the details of which product class should be instantiated.

 

4. Original Model mode: specify the type of the object to be created by providing a prototype object, and then create more objects of the same type by copying the prototype object. The original model mode allows you to dynamically add or remove product classes. The product class does not need to have any predefined level structure. The original model mode applies to any level structure. The disadvantage is that each class must have a clone method.

 

5. Singleton mode: Singleton mode ensures that only one instance is available for a class and the instance Singleton mode is self-instantiated and provided to the entire system. The Singleton mode can only be used when there is a real "Single Instance" demand.

 

6. adapter (transformer) mode: converts an interface of a class into another interface that the client expects, so that the two classes that cannot work together due to interface mismatch can work together. The adaptation class can return a suitable instance to the client based on the parameters.

 

7. Bridge Mode: This mode decouples abstraction and implementation so that the two can change independently, that is, the strong association between them becomes weak Association, that is, the combination/aggregation relationship is used between the abstraction and implementation of a software system, rather than the inheritance relationship, so that the two can change independently.

 

8. merging mode: the merging mode organizes objects into the tree structure and can be used to describe the relationship between the whole and the part. The merging mode is a tree structure mode for processing objects. The merging mode shows the relationship between the part and the whole in a tree structure. The merging mode allows the client to view individual component objects in the same way as the compositing objects composed of them.

 

9. decoration mode: The decoration mode extends the object functions in a transparent way to the client. It is an alternative to the inheritance relationship and provides more flexibility than inheritance. Dynamically adds features to an object, which can be dynamically revoked. A large number of functions are generated by the arrangement and combination of some basic functions.

 

10. Facade mode: external communication with a sub-system must be performed through a unified facade object. The facade mode provides a high-level interface to make subsystems easier to use. Each subsystem has only one portal class, and this portal class has only one instance, that is, it is a singleton mode. However, the entire system can have multiple portals.

 

11. Enjoy mode: FLYWEIGHT is the most lightweight in boxing. The metadata mode efficiently supports a large number of fine-grained objects in a shared manner. The key to the sharing mode is to distinguish between the internal and external states. The internal status is stored in the shared element and will not change with the environment. The external state changes with the change of the environment. The external status cannot affect the internal status. They are independent of each other. The States that can be shared and those that cannot be shared are separated from the conventional classes to remove the States that cannot be shared from the classes. The client cannot directly create shared objects, but should use a factory object to create shared objects. The metadata mode greatly reduces the number of objects in the memory.

 

12. Proxy mode: the proxy mode provides a proxy object for an object and controls the reference to the source object. An agent is an action taken by one person or institution on behalf of another person or institution. In some cases, the customer does not want or cannot directly reference an object. The proxy object can serve as an intermediary between the customer and the target object. The client cannot identify the proxy topic object and the real topic object. The proxy mode is acceptable.

13. responsibility chain mode: In the responsibility chain mode, many objects are referenced by each object to its next home.

 

To form a chain. Requests are transmitted on this chain until an object on the chain decides to process this request. The customer does not know which object on the chain finally processes this request. The system can dynamically reorganize the chain and assign responsibility without affecting the client. The handler has two options: Take responsibility or push the responsibility to the next house. A request cannot be accepted by any receiving end object.

 

14. Command mode: The command mode encapsulates a request or operation into an object. The command mode separates the responsibility for issuing commands from the responsibility for executing commands and delegates them to different objects. In command mode, the requester and the sender are allowed to be independent, so that the requester does not have to know the interfaces of the receiver, how the request is received, and whether the operation is executed, when and how it is executed. The system supports command revocation.

 

15. interpreter mode: Given a language, interpreter mode can define a representation of its syntax and provide an interpreter at the same time. The client can use this interpreter to explain sentences in this language. The interpreter mode describes how to explain these statements with a simple syntax. The language mentioned in the interpreter mode refers to any combination that any interpreter object can interpret. In the interpreter mode, you need to define a hierarchical structure of a command class that represents grammar, that is, a series of combination rules. Each command object has an interpretation method, which represents an interpretation of the command object. Any permutation and combination of objects in the hierarchical structure of command objects is a language.

 

16. Iteration sub-mode: the iteration sub-mode can access elements in an aggregation sequentially without exposing the internal representation of the aggregation. The aggregation of multiple objects is called aggregation. Clustering objects are container objects that can accommodate a group of objects. The iteration sub-mode encapsulates the iteration logic into an independent sub-object, which is separated from the aggregation itself. The iteration submode simplifies the aggregation interface. Each clustering object can have one or more iteration sub-objects. The iteration status of each iteration sub-object can be independent of each other. The iteration algorithm can be independent from the clustering role changes.

 

17. Called by mode: The called by mode encapsulates a series of ways in which objects interact, so that these objects do not have to interact explicitly. So that they can be loosely coupled. When the roles of some objects change, the roles of other objects are not immediately affected. Ensure that these functions can be changed independently of each other. The mediator mode converts the multi-to-many interaction into one-to-many interaction. The mediation mode abstracts the behavior and collaboration of objects, and processes the interaction between objects and other objects on a small scale.

 

18. Memorandum mode: A memorandum object is an object used to store snapshots of the internal state of another object. The purpose of the memorandum mode is to catch the state of an object without damaging the encapsulation, and store it externally, in this way, this object can be restored to the stored state when appropriate in the future.

 

19. Observer mode: The Observer mode defines a multi-team dependency, allowing multiple observer objects to listen to a single topic object at the same time. When the status of this topic object changes, it notifies all observer objects so that they can automatically update themselves.

 

20. State mode: State mode allows an object to change its behavior when its internal state changes. This object seems to have changed its class. The state pattern encapsulates the behavior of the studied object in different State objects. Each State object belongs to a subclass of an abstract state class. The intention of the state mode is to change the behavior of an object when its internal state changes. The State mode creates a subclass of the state class for the possible states of each system. When the system status changes, the system changes the selected subclass.

 

21. Policy mode: the Policy mode encapsulates each algorithm into an independent class with a common interface for a group of algorithms so that they can be replaced with each other. The policy mode allows the algorithm to change without affecting the client. Rule mode separates behavior from environment. The environment class is responsible for maintaining and querying behavior classes, and various algorithms are provided in specific policy classes. Because the algorithm and environment are independent, the increase, decrease, and modification of the algorithm will not affect the environment and the client.

 

22. template method mode: The template method mode prepares an abstract class, implements part of the logic in the form of a specific method and a specific constructor, and then declares some abstract methods to force the subclass to implement the remaining logic. Different sub-classes can implement these abstract methods in different ways to implement the rest logic differently. First, create a top-level logic framework, and leave the logic details to specific sub-classes for implementation.

 

23. Visitor mode: the visitor mode aims to encapsulate operations applied to certain data structure elements. Once these operations need to be modified, the data structure that accepts the operation can remain unchanged. The visitor mode is suitable for systems with relatively undetermined data structures. It frees the coupling between the data structure and the operations acting on the structure, allowing the operation set to evolve freely. The visitor mode makes it easy to add new operations, that is, to add a new visitor class. In the visitor mode, the related behaviors are concentrated in a visitor object, rather than scattered into node classes. When using the visitor mode, put as many object browsing logic as possible in the visitor class, rather than in its subclass. The visitor mode allows you to access member classes of different hierarchies over the hierarchical structure of several classes.