链表实现Map
public class LinkListMap<K,V> implements Map<K,V> {
private class Node
{
public K key;
public V value;
public Node next;
public Node(K key,V value,Node next)
{
this.key = key;
this.value = value;
this.next = next;
}
public Node()
{
this(null,null,null);
}
public Node(K key)
{
this(key,null,null);
}
@Override
public String toString()
{
return key.toString() + ":" + value.toString();
}
}
private Node dummyHead;
private int size;
public LinkListMap()
{
dummyHead = new Node();
size = 0;
}
private Node getNode(K key)
{
Node cur = dummyHead.next;
while (cur != null)
{
if (cur.key.equals(key))
{
return cur;
}
cur = cur.next;
}
return null;
}
@Override
public void add(K key, V value) {
Node node = getNode(key);
if (node == null)
{
dummyHead.next = new Node(key,value,dummyHead.next);
size++;
}else {
node.value = value;
}
}
@Override
public V remove(K key) {
Node prv = dummyHead;
while (prv.next != null)
{
if (prv.next.key.equals(key))
{
break;
}
prv = prv.next;
}
if (prv.next != null)
{
Node delNode = prv.next;
prv.next = delNode.next;
delNode.next = null;
return delNode.value;
}
return null;
}
@Override
public boolean contains(K key) {
return getNode(key) != null;
}
@Override
public V get(K key) {
Node node = getNode(key);
return node == null ? null : node.value;
}
@Override
public void set(K key, V newValue) {
Node node = getNode(key);
if (node == null)
{
throw new IllegalArgumentException("key is no exist.");
}else {
node.value = newValue;
}
}
@Override
public int getSize()
{
return size;
}
@Override
public boolean isEmpty()
{
return size == 0;
}
@Override
public String toString()
{
StringBuffer str = new StringBuffer("");
Node node = dummyHead.next;
while (node != null)
{
str.append(node + "\n");
node = node.next;
}
return str.toString();
}
}