概念理解

組合模式用來表示整體和部分的結(jié)構(gòu)君仆，是一種結(jié)構(gòu)型模式。對于客戶端而言牲距，整體和部分開放的是同一個接口返咱，調(diào)用起來并沒有不同。換種說法牍鞠，一個對象和一組對象對于客戶端而言咖摹，使用方式是一致的。

實例說明

組合模式的典型表示方式是樹形結(jié)構(gòu)难述，實例有很多萤晴，比如文件系統(tǒng)，網(wǎng)站菜單胁后，公司和部門之間的關(guān)系店读，員工領(lǐng)導(dǎo)和下屬的關(guān)系。現(xiàn)在考慮員工和下屬的關(guān)系攀芯，實現(xiàn)起來非常簡單:不管是領(lǐng)導(dǎo)還是員工屯断，都使用同一個類雇員，雇員中有名字侣诺，薪水殖演，部門，和管理的下屬員工年鸳。底層員工的下屬員工列表為空剃氧，并不影響調(diào)用。

public class Employee {

    private String name;
    private String dept;
    private int salary;
    private List<Employee> subordinate;

    public Employee(String name, String dept, int salary) {
        this.name = name;
        this.dept = dept;
        this.salary = salary;
        subordinate = new ArrayList<Employee>();
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDept() {
        return dept;
    }

    public void setDept(String dept) {
        this.dept = dept;
    }

    public int getSalary() {
        return salary;
    }

    public void setSalary(int salary) {
        this.salary = salary;
    }

    public List<Employee> getSubordinate() {
        return subordinate;
    }

    public void setSubordinate(List<Employee> subordinate) {
        this.subordinate = subordinate;
    }

    public void addEmployee(Employee e) {
        this.subordinate.add(e);
    }

    @Override
    public String toString() {
        return "name=" + name + ",dept=" + dept + ",salary=" + salary;
    }
}

public class App {
    public static void main(String[] args) {
        Employee chief = initEmployee();
        printEmployee(chief);

    }

    public static void printEmployee(Employee e){
        System.out.println(e.toString());
        List<Employee> subordinates = e.getSubordinate();
        for(int i =0;i<subordinates.size();i++){
            printEmployee(subordinates.get(i));
        }
    }

    public static Employee  initEmployee() {
        Employee chief = new Employee("SAM", "Finance", 10000);
        Employee leader = new Employee("tom", "Finance", 7000);
        Employee amy = new Employee("amy", "Finance", 4000);
        Employee sary = new Employee("sary", "Finance", 4000);
        chief.addEmployee(leader);
        chief.addEmployee(sary);
        leader.addEmployee(amy);
        return chief;
    }
}

代碼實例參見：https://github.com/jxl198/designPattern/tree/master/composite