一个LRUCache实现

我写的一个LRUCache的实现

import java.util.Hashtable;public class LRUCache {    class CacheNode {        CacheNode prev;        CacheNode next;        Object key;        Object value;    }    private int cacheSize;    private int currentSize;    private Hashtable<Object,CacheNode> nodes;    private CacheNode first;    private CacheNode last;    public LRUCache(){}    public LRUCache(int size){        this.cacheSize = size;        this.nodes = new Hashtable<Object,CacheNode>(size);        this.currentSize = 0;    }    public void moveToHead(CacheNode node){        if(first == node){            return;        }        if(node.prev != null){            node.prev = node.prev.next;        }        if(node.next != null){            node.next.prev = node.prev;        }        if(last == node){            last = node.prev;        }        if(first != null){            first.prev = node;            node.next = first;        }        first = node;        node.prev = null;        if(last == null){            last = first;        }    }    public void removeLast(){        if(last != null){            if(last.prev != null){                last.prev.next = null;            } else {                first = null;            }            last = last.prev;            nodes.remove(last.key);            currentSize--;        }    }    public void put(Object key, Object value){        CacheNode node = nodes.get(key);        if(node == null){            if(currentSize >= cacheSize){                if(last != null){                    nodes.remove(key);                }                removeLast();            } else {                currentSize++;            }            node = new CacheNode();        }        node.key = key;        node.value = value;        moveToHead(node);        nodes.put(key, node);    }    public Object get(Object key){        CacheNode node = nodes.get(key);        if(node != null){            moveToHead(node);            return node.value ;        }        return null;    }    public Object remove(Object key){        CacheNode node = nodes.get(key);        if(node != null){            if(node.prev != null){                node.prev.next = node.next;            } else {                first = null;            }            if(node.next != null){                node.next.prev = node.prev;            }            if(first == node){                first = node.next;            }            if(last == node){                last = node.prev;            }            nodes.remove(key);            currentSize--;            return node.value;        }        return null;    }}