LinkedList源码（基础代码）

LinkedList是由一个一个节点连接起来的链表private static class Node<E> { E item; Node<E> next; Node<E> prev; Node(Node<E> prev, E element, Node<E> next) { this.item = element; this.next = next; this.prev = prev; } }增 public boolean add(E e) { linkLast(e); return true; } public void addFirst(E e) { linkFirst(e); } private void linkFirst(E e) { final Node<E> f = first; final Node<E> newNode = new Node<>(null, e, f); first = newNode; if (f == null) last = newNode; else f.prev = newNode; size++; modCount++; } public void addLast(E e) { linkLast(e); } void linkLast(E e) { final Node<E> l = last; final Node<E> newNode = new Node<>(l, e, null); last = newNode; if (l == null) first = newNode; else l.next = newNode; size++; modCount++; }删 public boolean remove(Object o) { if (o == null) { for (Node<E> x = first; x != null; x = x.next) { if (x.item == null) { unlink(x); return true; } } } else { for (Node<E> x = first; x != null; x = x.next) { if (o.equals(x.item)) { unlink(x); return true; } } } return false; } public E remove(int index) { checkElementIndex(index); return unlink(node(index)); }改 public E set(int index, E element) { checkElementIndex(index); Node<E> x = node(index); E oldVal = x.item; x.item = element; return oldVal; }查 public E get(int index) { checkElementIndex(index); return node(index).item; }其他 // 检索出第一个元素，但不取出 public E peek() { final Node<E> f = first; return (f == null) ? null : f.item; } // 检索出第一个元素，同时取出 public E poll() { final Node<E> f = first; return (f == null) ? null : unlinkFirst(f); }