Overview
The relationship between the classes and the degree of coupling from high to low:
- It is. Inheritance, realization
- It has. Combination, polymerization, association
- use. rely.
Requirements are: high cohesion and low coupling.
inherit
Is the inheritance relationship between Person and Man.
achieve
combination
public class Person {
// Person和Heart之间是组合
private Heart h;
public Person(){
h=new Heart();
}
}Features are: To create an object in the constructor
polymerization
public class Car {
//聚合
private Engine e;
public Car(Engine e){
this.e = e;
}
}Aggregation features are: has the property, and to be used in the constructor, but not created in the constructor method.
Note that a combination of differences: both the opportunity to create a different combination is created when Person was created. Polymerization can be created in the other.
Related
public class Person {
// Person 和Car之间是关联关系
private Car c;
public void setC(Car c){
this.c=c;
}
}It characterized by: not set in the configuration process.
rely
public class Person {
// 使用-依赖
public void traval(Train t){
}
}Features are: to be used in ordinary methods.
