crest design template

that the instance must be created automatically and provided externally.　　AdvantagesThere is only one object in system memory, so system resources can be saved, and for some object singleton patterns that need to be created and destroyed frequently, the performance of the system can be improved.　　DisadvantagesThere is no abstraction layer, so the extension is difficult.Too heavy a duty to violate a single duty in a certain procedureTemplate design mo

Define: Define the skeleton of an algorithm in an operation, deferring some steps to subclasses. template method lets subclasses redefine certain steps of an algorithm without changing the algorithm's structure.1. template method mode Prepare an abstract class, implement part of the logic in the form of a specific method and a specific constructor, and then declare some abstract methods to force the subclas

I. Demand analysis The steps to solve a certain kind of thing are fixed, at which point we can provide a template code for this kind of thing, thereby increasing the efficiency Second, the pattern design: 1. Write a solution to one thing in this category (including the template section and the change section)2. Extract the changed parts into a method that desc

1. Template method Mode Prepare an abstract class, implement part of the logic in the form of concrete methods and concrete constructs, and then declare some abstract methods to force subclasses to implement the remaining logic. Different subclasses can implement these abstract methods in different ways, thus having different implementations of the remaining logic. This is the purpose of the template metho

Prepare an abstract class, implement part of the logic in the form of concrete methods and concrete constructs, and then declare some abstract methods to force subclasses to implement the remaining logic. Different subclasses can implement these abstract methods in different ways, thus having different implementations of the remaining logic. This is the purpose of the template method pattern. Many people may not think that the

Because of its own defects, the inheritance relationship has been detained by experts as "evil. Experts such as "using delegate relationships instead of inheritance relationships" and "Using Interfaces as much as possible instead of abstract class inheritance" warn us that these cainiao will "look at inheritance differently ". In fact, inheritance still has many advantages. It seems that the disadvantages are even more obvious. The rational use of the inheritance relationship can still play a go

Defines the algorithm skeleton in an operation, and delays some steps to the subclass, so that the subclass can not change the structure of an algorithm, but define some specific steps of the algorithm inheritance relationship due to its own defects, the experts have taken down the "evil" hat. Experts such as "using delegate relationships instead of inheritance relationships" and "using interfaces as much as possible instead of abstract class inheritance" warn us that these Cainiao will "look at

methods that subclass may override; 3. UML In the UML diagram, the templatemethod in the parent class is an abstract method, which calls four methods in a certain order-primitiveopertion1, primitiveopertion2, concreteopertion, and hook. primitiveopertion1 and operator are abstract methods, child classes are required to be implemented based on specific conditions, but the overall framework of the algorithm is controlled by the templatemethod method in the parent class. 4. UseFor the c

Due to its own shortcomings, the inheritance relationship has been buttoned up by experts on the "evil" hat. "Use delegated relationships instead of inheritance relationships", "Try to use interface implementations instead of abstract class inheritance" and so on experts warn, let us these rookie to inherit "Respect". In fact, inheritance or have a lot of their own advantages. It seems that the shortcomings are more obvious than those abused by everyone. Reasonable use of the inheritance relatio

Defines the algorithm skeleton in an operation, and delays some steps to the subclass, so that the subclass can not change the structure of an algorithm, but define some specific steps of the algorithm inheritance relationship due to its own defects, the experts have taken down the "evil" hat. Experts such as "using delegate relationships instead of inheritance relationships" and "using interfaces as much as possible instead of abstract class inheritance" warn us that these Cainiao will "look at

"Design pattern Refinement" Learning notes (14) ------Template method (Template method) mode GOF : defines the skeleton of an algorithm in an operation, and delays some steps into subclasses. Template method enables subclasses to redefine certain steps of the algorithm without altering the structure of an algorithm