java 泛型知识点综合 之 示例程序

package NEW_DATE_SEQUENCE_PACKAGE;

public class J_8_30_2
{
public static void main(String[] args)
{
Manager ceo=new Manager("hello",80);
Manager cfo=new Manager("well",10);
Pair1<Manager> buddies=new Pair1<>(ceo,cfo);
printBuddies(buddies);

ceo.setBonus(100000);
cfo.setBonus(1);

Manager[] managers={ceo,cfo};

Pair1<Employee> result=new Pair1<>();
minmaxBonus(managers,result);

System.out.println("first: "+result.getFirst().getName()+" second: "+result.getSecond().getName());
maxminBonus(managers,result);
System.out.println("first: "+result.getFirst().getName()+" second: "+result.getSecond().getName());

}
public static void printBuddies(Pair1 <? extends Employee>  p)
{
Employee first=p.getFirst();
Employee second =p.getSecond();
System.out.println(first.getName()+" and "+second.getName()+" is buddies");

}

public static void minmaxBonus(Manager[] a,Pair1<? super Manager> result)
{
Manager min=a[0];
Manager max=a[0];
for(int i=0;i<a.length;++i)
{
if(a[i].getBonus()<min.getBonus())
min=a[i];
if(a[i].getBonus()>max.getBonus())
max=a[i];
result.setFirst(min);
result.setSecond(max);

}
}

public static void maxminBonus(Manager[] a,Pair1<? super Manager> result)
{
minmaxBonus(a,result);
PairAlg.swap(result);   //?
}

}
class PairAlg
{
public static boolean hasNull(Pair1<?> p)
{
return p.getFirst()==null || p.getSecond()==null;
}

public static void swap(Pair1<?> p)
{
swapHelper(p);
}
public static <T> void swapHelper(Pair1<T> p)
{
T t=p.getFirst();
p.setFirst(p.getSecond());
p.setSecond(t);
}

}

class Employee
{
private double salary;
private String name;
private double bonus;

public Employee(String name,double salary)
{
this.name=name;
this.salary=salary;

this.bonus=0;
}
public double getSalary()
{
return salary;
}
public String getName()
{
return name;
}
public double getBonus()
{
return bonus;
}
public void setBonus(double bonus)
{
this.bonus=bonus;
}
}
class Manager extends Employee
{
public Manager(String name,double salary)
{
super(name,salary);

}
public void setBonus(double bonus)
{
super.setBonus(bonus);

}

}
class Pair1<T>
{
private T first;
private T second;
public Pair1()
{

}
public Pair1(T first,T second)
{
this.first=first;
this.second=second;
}
public void setFirst(T t)
{
this.first=t;
}
public void setSecond(T t)
{
this.second=t;
}

public T getFirst()
{
return  first;
}
public T getSecond()
{
return second;
}
}