设计模式-?组合模式

自己管理自己

abstract class Employer{
    private String name;
    public void setName(String name){
        this.name = name;
    }

    public String getName() {
        return name;
    }
    public abstract void add(Employer employer);
    public abstract void delete(Employer employer);

    public List employers;

    public void printInfo(){
        System.out.println(name);
    }
    public List getEmployers(){
        return this.employers;
    }
}

class Programmer extends Employer{
   public Programmer(String name){
       setName(name);
       employers = null;
   }
    public void add(Employer employer){}
    public void delete(Employer employer){}

}

class ProjectAssistant extends Employer{
    public ProjectAssistant(String name){
        setName(name);
        employers =null;
    }
    public void add(Employer employer){}
    public void delete(Employer employer){}
}

class ProjectManager extends Employer{
    public ProjectManager(String name){
        setName(name);
        employers = new ArrayList();
    }
    public void add(Employer employer){
        employers.add(employer);
    }
    public void delete(Employer employer){
        employers.remove(employer);
    }
}

public class ComponentTest {
    public static void main(String[] args){
        Employer pm =new ProjectManager("pm");
        Employer pa = new ProjectAssistant("pa");
        Employer p1 = new Programmer("p1");
        Employer p2 = new Programmer("p2");

        pm.add(pa);
        pm.add(p2);

        List ems = pm.getEmployers();
        for(Object em:ems){
            System.out.println(((Employer)em).getName());
        }

    }
}