Learn martial arts, how important the mind is. For example, those who practice wrong mind method, such as Uncle Ouyang Feng, wrong mind method, went astray, died on the top of Huashan mountain. Also some must first from the palace of martial arts, perhaps the back of a page on the previous page is not needed. So the six principles, we also understand the heart, to practice good martial arts ah.
Let’s start with an overview of the six principles of design patterns.
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1, the open closed principle | open for extension, but closed for modification.
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2, the principle of substitution on the Richter scale | subclasses can do instead of the base class.
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3, dependency inversion principle | for interface programming, relies on the abstract rather than concrete.
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4, the interface segregation principle | use multiple isolated interface, it is better than using a single interface. (Reduce coupling between classes)
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5, Demeter (at least know principle) | an entity shall, as far as possible to interact with other entities.
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6 and the responsibilities of the single | a class should have only one reason of the change of the it, a duty.
Of course, this is still too abstract, the following will be divided into 4 days (4) small comics + code to explain in detail ~
The first day
Last link: Design patterns start
public class Animal {
public void eat(a) {
System.out.println("eat something");
}
public void sleep(a) {
System.out.println("sleeping ~~"); } } Copy the code
public void eat (String kind) {
if (kind.equals("rabbit")) {
System.out.println("eat some carmine");
}
if (kind.equals("tigger")) {
System.out.println("eat some meat"); } } Copy the code
public class Rabbit extends Animal {
public void eat(a) {
System.out.println("eat some carmine");
}
}
Copy the code
public class Cooker {
public void cook(Potato potato) {
System.out.println("Let's start cooking.");
System.out.println(potato.getFood());
}
} class Potato { public String getFood(a) { return "Hot and sour potato shreds"; } } Copy the code
public interface FoodMaterial {
String getFood(a);
}
class Potato implements FoodMaterial{
@Override public String getFood(a) { return "Hot and sour potato shreds"; } } class Chicken implements FoodMaterial{ @Override public String getFood(a) { return "Coke Chicken Wings"; } } public class Cooker { public void cook(FoodMaterial foodMaterial) { System.out.println("Let's start cooking."); System.out.println(foodMaterial.getFood()); } public static void main (String []args) { Cooker cooker = new Cooker(); cooker.cook(new Potato()); } } Copy the code
The second day
public interface EmployService {
void sign (a); / / clock
void knockCode(a);/ / type code
void recruit(a); / / recruitment
void relationShip(a); // Employee relations void performanceEvaluation(a); // Performance management void procedureDesign(a); // Program design void makeBugs(a); / / ha ha ha } public class HrServiceImpl implements EmployService{ @Override public void sign(a) { System.out.println("Clock"); } @Override public void knockCode(a) { } @Override public void recruit(a) { System.out.println("Recruiting"); } @Override public void relationShip(a) { System.out.println("Employee Relations"); } @Override public void performanceEvaluation(a) { System.out.println("Performance Appraisal"); } @Override public void procedureDesign(a) { } @Override public void makeBugs(a) { } } public class ProgrammerServiceImpl implements EmployService { @Override public void sign(a) { System.out.println("Clock"); } @Override public void knockCode(a) { System.out.println("Knock code"); } @Override public void recruit(a) { } @Override public void relationShip(a) { } @Override public void performanceEvaluation(a) { } @Override public void procedureDesign(a) { System.out.println("Programming"); } @Override public void makeBugs(a) { System.out.println("Build some bug"); } } public class ProgrammerClient { public void sign (EmployService employService) { employService.sign(); } public void knockCode(EmployService employService) { employService.knockCode(); } public void procedureDesign(EmployService employService) { employService.procedureDesign(); } public void makeBugs(EmployService employService) { employService.makeBugs(); } } public class HrClient { public void sign (EmployService employService) { employService.sign(); } public void performanceEvaluation(EmployService employService) { employService.performanceEvaluation(); } public void recruit(EmployService employService) { employService.recruit(); } public void relationShip(EmployService employService) { employService.relationShip(); } } Copy the code
public interface EmployService {
void sign(a); / / clock
}
public interface HrService {
void recruit(a); / / recruitment void relationShip(a); // Employee relations void performanceEvaluation(a); // Performance management } public class HrServiceImpl implements HrService.EmployService{ @Override public void sign(a) { System.out.println("Clock"); } @Override public void recruit(a) { System.out.println("Recruiting"); } @Override public void relationShip(a) { System.out.println("Employee Relations"); } @Override public void performanceEvaluation(a) { System.out.println("Performance Management"); } } public interface ProgrammerService { void knockCode(a);/ / type code void procedureDesign(a); // Program design void makeBugs(a); / / ha ha ha } public class ProgrammerServiceImpl implements ProgrammerService.EmployService { @Override public void sign(a) { System.out.println("Sign in"); } @Override public void knockCode(a) { System.out.println("Knock code"); } @Override public void procedureDesign(a) { System.out.println("Programming"); } @Override public void makeBugs(a) { System.out.println("Build some bug"); } } Copy the code
On the third day
public interface CarService{
String getName ();
void drive ();
String color();
}
public class Sedan implements CarService { private String name; private String color; private int speed; public Sedan(String name, String color,int speed{ this.name = name; this.color = color; this.speed = speed; } @Override public String getName() { return this.name; } @Override public void drive() { System.out.println("Ordinary car, ordinary driving." + this.speed); } @Override public String color() { return this.color; } } Copy the code
public class FastSedan extends Sedan {
public FastSedan(String name, String color, int speed) {
super(name, color, speed);
}
public void drive(a) { System.out.println("Go for it, go for it." + this.getSpeed() * 2); } } Copy the code
public class Boss {
// Publish tasks to the CTO public void pushJob(CTO cto) {
List<Programmer> list = new ArrayList<Programmer>();
for(int i = 0; i < 5; i++) { list.add(new Programmer()); } cto.assignmentTask(list); } } public class CTO { // Assign tasks public void assignmentTask(List<Programmer> programmers) { for (Programmer programmer:programmers) { programmer.backPot(); } } } public class Programmer { / / pot back public void backPot () { System.out.println("The programmer carries the pan on his back."); } } public class Client { public static void main (String []args) { Boss boss = new Boss(); boss.pushJob(new CTO()); } } Copy the code
The last day
Let’s consolidate
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