JAVA design patterns (1) Summary of design patterns

There are three types of design patterns: creation, structure, and behavior. Among them, the creation type is: 1. Singleton. Singleton mode: ensure that a class has only one instance, and provide a global access point to it. 2. Abstract Factory, Abstract Factory: provides an interface for creating a series of related or mutually dependent objects without specifying their specific classes. 3. Factory Method: Define an interface used to create objects, and let the subclass decide which class to instantiate. Factory Method delays the instantiation of a class to the subclass. 4. Builder: separates the construction of a complex object from its representation, so that different representations can be created during the same construction process. 5. Prototype: Use a Prototype instance to specify the type of the object to be created, and copy the Prototype to create a new object. Behavior types: 6. Iterator. Iterator mode: provides a method to access each element of an aggregate object sequentially without exposing the internal representation of the object. 7. Observer: Observer mode: defines one-to-many dependencies between objects. When the status of an object changes, all objects dependent on it will be automatically updated by notification. 8. Template Method: defines the skeleton of an algorithm in an operation, and delays some steps to the subclass, templateMethod allows the subclass to redefine a specific step without changing the structure of an algorithm. 9. Command: encapsulate a request as an object so that you can parameterize the customer with different requests, queue requests and record request logs, and supports unrecoverable operations. 10. State: allows an object to change its behavior when its internal State changes. The object seems to have changed its class. 11. Strategy: Define a series of algorithms, encapsulate them one by one, and enable them to replace each other. This mode allows algorithms to be independent of customers who use them. 12. China of Responsibility, Responsibility chain mode: Enables multiple objects to process requests, so as to avoid coupling between the request sender and receiver. 13. Mediator. intermediary mode: encapsulate object interaction of some columns with an intermediary object. 14. Visitor, Visitor mode: indicates an operation that acts on each element in an object structure. It allows you to define new operations that act on this element without changing the element classes. 15th, Interpreter, Interpreter mode: a language is defined to define a representation of its grammar and an Interpreter. This Interpreter uses this representation to explain sentences in the language. 16. Memento: capture the internal state of an object without interrupting the object, and save the state outside the object. Structural types include: 17 and Composite. Combination Mode: the object is combined into a tree structure to represent the relationship between the whole part. Composite makes the use of a single object and the combination object consistent. 18. Facade, appearance mode: provides a consistent interface for a group of interfaces in the subsystem. fa? Ade provides a high-level interface, which makes the subsystem easier to use. 19. Proxy: provides a Proxy for other objects to control access to this object. 20. Adapter. Adapter mode: the Adapter mode converts a class-1 interface to another interface that the customer wants. The Adapter mode makes those classes unable to work together due to incompatibility of the interface. 21. Decrator: the Decorator mode dynamically adds some additional responsibilities to an object. In terms of the added functions, the Decorator mode is more flexible than the subclass generation mode. 22. Bridge: separates the abstract part from its implementation part so that they can change independently. Twenty-three, Flyweight, metadata-Sharing Mode