Question

我正在为人类开设课程，我对此有一两个问题。

/**
 * ADT for persons which is completed which subclasses
 * to creating actors with specific properties
*/
public class Person {

    /**
     * Name of the Person.
     */
  public String name;

    /**
     * The World which this Person is associated with.
     */
  public World world;

    /**
     * Tells where this Person is at the moment.
     */
  public Place where;

    /**
     * The inventory, contains Things.
     */
  public Collection<Thing> inventory;

    /**
     * Shows how the Person looks like
     */
  public Image appearance;

    /**
     * Create Person named `name' in world `world'.
     * 
     * @param world The world where the Person is created.
     * @param name Name of the Person.
     * @param app An image used to display the Person.
     */
  public Person( World world, String name, Image app ) {
    this.world = world;
    this.name = name;
    this.appearance = app;

    where = world.defaultPlace();
    where.enter( this );

    inventory = Collections.synchronizedCollection( new LinkedList() );
  }

...

Person类是公开还是默认访问权限更好？一个人，一个私人人应该公开并不是有点奇怪，即使这里的含义不完全相同。
当我的IDE警告inventory = Collections.synchronizedCollection( new LinkedList() );时，我该如何处理arning？它警告我的类型安全。

谢谢

Answer 1

如果Person只在一个包中使用，您可以将其设为默认值。否则public有意义。

尝试提供通用类型。

List<Person> people = Collections.synchronizedList(new LinkedList<Person>());

Answer 2

对于警告，您需要指定LinkedList的元素类型：

inventory = Collections.synchronizedCollection( new LinkedList<Thing>());

至于private的{{1}} / public：如果类 Person标记为Person，则表示其他代码（其包装的其他部分）可以根据需要参考/使用它。当您将public类型的成员变量声明为Person时，这意味着其他代码无法直接访问成员变量。两者互不影响

如何修复此警告？

2 个答案: