Inheritance I: Interface and Implementation Inheritance
9.2 Hypernyms, Hyponyms, and the Implements Keyword
interface 类：
public interface List61B<Item> {
public void addFirst(Item x);
public void add Last(Item y);
public Item getFirst();
public Item getLast();
public Item removeLast();
public Item get(int i);
public void insert(Item x, int position);
public int size();
}
实现类：
public class AList<Item> implements List61B<Item>{...}
9.3 Overriding, Interface Inheritance
overriding
实现类实现 interface 类的时候要加上@Override关键字。
@Override
public void addFirst(Item x) {
insert(x, 0);
}
9.4 Implementation Inheritance, default
interface 类可以实现默认的 method:
default public void print() {
for (int i = 0; i < size(); i += 1) {
System.out.print(get(i) + " ");
}
System.out.println();
}
对于 SLList 类，这种默认的实现方式效率不高，因为链表每一次 get() 都是 O(n), 可以 override 默认 method:
@Override
public void print() {
for (Node p = sentinel.next; p != null; p = p.next) {
System.out.print(p.item + " ");
}
}