java 求救

[shenhang1111]

见代码：

import java.util.ArrayList;
import actor.Sheep;

public class BoundedGrid<E>
{
    private Object[][] occupantArray; // the array storing the grid elements

    public E get(Location loc)
    {
        if (!isValid(loc))
            throw new IllegalArgumentException("Location " + loc
                    + " is not valid");
        return (E) occupantArray[loc.getX()][loc.getY()];
    }



    public ArrayList<Location> getEmptyLocations(Location l)
    {
        ArrayList<Location> theLocations = new ArrayList<Location>();

        for (int r = -1; r < 2; r++)
        {
            for (int c = -1; c < 2; c++)
            {
                Location loc = new Location(l.getX() + r, l.getY() + c);
                if (loc.getX() >=0 && loc.getY() >=0 && get(loc) == null)//get(loc) == null就可以
                    theLocations.add(loc);
            }
        }
        return theLocations;
    }

    public ArrayList<Location> getSheepLocations(Location l)
    {
        ArrayList<Location> theLocations = new ArrayList<Location>();

        // Look at all grid locations.
        for (int r = -1; r < 2; r++)
        {
            for (int c = -1; c < 2; c++)
            {
                Location loc = new Location(l.getX() + r, l.getY() + c);
                if (loc.getX() >=0 && loc.getY() >=0 && get(loc) == Sheep)
//但是我希望判断loc这个位置是否是Sheep类的对象的时候就不行了，为什么呀？
                theLocations.add(loc);
            }
        }
        return theLocations;
    }

[shenhang1111]

原来是这样！谢谢啦~~看来得补补基础了··

[java1109]

get(loc) == Sheep这个语法不符合规范
判断是否为哪个类用 instanceof 关键字