文章目录
- 1.引出迭代器模式
-
- 2.迭代器模式解决院系结构展示问题
- 1.基本介绍
- 2.原理类图
- 3.类图
- 4.代码实现
- 1.Department.java 存储信息的对象
- 2.College.java 被迭代的类型接口
- 3.ComputerCollege.java 被迭代的具体实现类，存储数据并将其在创建迭代器的时候传进去
- 4.ComputerCollegeIterator.java 被实现的具体类的迭代器
- 5.InfoCollege.java 被迭代的具体类型
- 6.InfoColleageIterator.java 具体的迭代器
- 7.OutputImpl.java 统一输出信息的类
- 8.Client.java 客户端
- 5.注意事项和细节
- 3.迭代器模式在ArrayList的应用
- 观察者模式
- 1.引出观察者模式
- 1.天气预报项目需求
- 2.普通方案
- 3.普通方案问题分析
- 2.观察者模式解决天气预报
- 1.原理分析
- 2.类图
- 3.代码实现
- 1.Observer.java 观察者接口，可以更新自己的信息
- 2.CurrentConditions.java 具体的观察者
- 3.Subject.java 信息发布者的接口
- 4.WeatherData.java 具体的信息发布者，一旦更新信息就会更新观察者的信息
- 5.Client.java
- 6.结果
- 3.观察者模式在JDK的Observable类中的使用
1.引出迭代器模式
1.展示院系结构
2.传统方式
2.迭代器模式解决院系结构展示问题
1.基本介绍
2.原理类图
3.类图
4.代码实现
1.Department.java 存储信息的对象
package com.sun;
public class Department {private String name;private String desc;public Department(String name, String desc) {this.name = name;this.desc = desc;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getDesc() {return desc;}public void setDesc(String desc) {this.desc = desc;}
}
2.College.java 被迭代的类型接口
package com.sun;import java.util.Iterator;
public interface College {String getName();void addDepartment(String name, String desc);Iterator createIterator();}
3.ComputerCollege.java 被迭代的具体实现类，存储数据并将其在创建迭代器的时候传进去
package com.sun;import java.util.Iterator;
public class ComputerCollege implements College {Department[] departments;int numOfDepartment = 0;public ComputerCollege() {departments = new Department[3];addDepartment("java", "java");addDepartment("python", "python");addDepartment("go", "go");}@Overridepublic String getName() {return "计算机学院";}@Overridepublic void addDepartment(String name, String desc) {Department department = new Department(name, desc);departments[numOfDepartment++] = department;}@Overridepublic Iterator createIterator() {return new ComputerCollegeIterator(departments);}
}
4.ComputerCollegeIterator.java 被实现的具体类的迭代器
package com.sun;import java.util.Iterator;
public class ComputerCollegeIterator implements Iterator {Department[] departments;int position = 0;public ComputerCollegeIterator(Department[] departments) {this.departments = departments;}@Overridepublic boolean hasNext() {if(position >= departments.length || departments[position] == null) {return false;}return true;}@Overridepublic Object next() {Department department = departments[position];position += 1;return department;}@Overridepublic void remove() {Iterator.super.remove();}
}
5.InfoCollege.java 被迭代的具体类型
package com.sun;import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
public class InfoCollege implements College{List<Department> departmentList;public InfoCollege() {departmentList = new LinkedList<>();addDepartment("信息安全", "信息安全");addDepartment("网络安全", "网络安全");addDepartment("服务器安全", "服务器安全");}@Overridepublic String getName() {return "信息工程学院";}@Overridepublic void addDepartment(String name, String desc) {Department department = new Department(name, desc);departmentList.add(department);}@Overridepublic Iterator createIterator() {return new InfoColleageIterator(departmentList);}
}
6.InfoColleageIterator.java 具体的迭代器
package com.sun;import java.util.Iterator;
import java.util.List;
public class InfoColleageIterator implements Iterator {List<Department> departments;int index = -1;public InfoColleageIterator(List<Department> departments) {this.departments = departments;}@Overridepublic boolean hasNext() {if (index >= departments.size() - 1) {return false;}index += 1;return true;}@Overridepublic Object next() {return departments.get(index);}@Overridepublic void remove() {Iterator.super.remove();}
}
7.OutputImpl.java 统一输出信息的类
package com.sun;import java.util.Iterator;
import java.util.List;
public class OutputImpl {List<College> collegeList;public OutputImpl(List<College> collegeList) {this.collegeList = collegeList;}public void printCollege() {for (College college : collegeList) {System.out.println("=====" + college.getName() + "=====");Iterator iterator = college.createIterator();printDepartment(iterator);}}public void printDepartment(Iterator iterator) {while (iterator.hasNext()) {Department next = (Department) iterator.next();System.out.println(next.getName());}}}
8.Client.java 客户端
package com.sun;import java.util.LinkedList;
import java.util.List;
public class Client {public static void main(String[] args) {List<College> collegeList = new LinkedList<>();collegeList.add(new ComputerCollege());collegeList.add(new InfoCollege());OutputImpl output = new OutputImpl(collegeList);output.printCollege();}
}
5.注意事项和细节
3.迭代器模式在ArrayList的应用
观察者模式
1.引出观察者模式
1.天气预报项目需求
2.普通方案
3.普通方案问题分析
2.观察者模式解决天气预报
1.原理分析
2.类图
3.代码实现
1.Observer.java 观察者接口，可以更新自己的信息
package com.sun;
public interface Observer {void update(float temperature, float pressure, float humidity);}
2.CurrentConditions.java 具体的观察者
package com.sun;
public class CurrentConditions implements Observer{private float temperature;private float pressure;private float humidity;@Overridepublic void update(float temperature, float pressure, float humidity) {this.temperature = temperature;this.humidity = humidity;this.pressure = pressure;display();}public void display() {System.out.println("Today's temperature: " + temperature);System.out.println("Today's pressure: " + pressure);System.out.println("Today's humidity: " + humidity);}}
3.Subject.java 信息发布者的接口
package com.sun;
public interface Subject {void registerObserver(Observer o);void removeObserver(Observer o);void notifyObservers();}
4.WeatherData.java 具体的信息发布者，一旦更新信息就会更新观察者的信息
package com.sun;import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class WeatherData implements Subject{private float temperature;private float pressure;private float humidity;private List<Observer> observerList;public WeatherData() {observerList = new ArrayList<>();}public void setData(float temperature, float pressure, float humidity) {this.humidity = humidity;this.pressure = pressure;this.temperature = temperature;changeData();}public void changeData() {notifyObservers();}@Overridepublic void registerObserver(Observer o) {observerList.add(o);}@Overridepublic void removeObserver(Observer o) {observerList.remove(o);}@Overridepublic void notifyObservers() {Iterator<Observer> iterator = observerList.iterator();while (iterator.hasNext()) {Observer next = iterator.next();next.update(temperature, pressure, humidity);}}}
5.Client.java
package com.sun;
public class Client {public static void main(String[] args) {WeatherData weatherData = new WeatherData();CurrentConditions currentConditions = new CurrentConditions();weatherData.registerObserver(currentConditions);weatherData.setData(200, 200, 200);weatherData.setData(100, 100, 100);}}
6.结果
3.观察者模式在JDK的Observable类中的使用
