Java Notes-10

Summay: The Map Interface, Collection implementations

-Maps store and retrieve elements with key values

e.g:

Map<String, Date> dateMap = new HashMap<String, Date>();
dateMap.put( "today", new Date() );
Date today = dateMap.get( "today" );

-Functions:

public V put( K key , V value )//This method adds the specified key/value pair to the map.
public V get( K key )//This method retrieves the value corresponding to key from the map.
public V remove( K key )//This method removes the value corresponding to key from the map
public int size()//Use this method to find the number of key/value pairs in this map
public Set keySet()//This method returns a Set that contains all the keys in this map.
public Collection values()//Use this method to retrieve all the values in this map

-Map has one child interface,  SortedMap . A  SortedMap maintains its key/value pairs sorted
in a particular order according to the key values. 

-All of the methods of the  Collection interface would appear to make sense for  Map ,
except for  iterator() . A  Map , again, has two sets of objects: keys and values, and separate
iterators for each. This is why a  Map does not implement  Collection 

-ConcurrentMap, It extends the base  Map interface and adds atomic put, remove, and replace functionality that is
useful for concurrent programming

public V putIfAbsent( K key, V value )//This method associates the value with the key only if the key was not already in use.
public boolean remove( Object key, Object value )//This method removes the mapping (key and value) only if the current value asso

波比源码 – 精品源码模版分享 | www.bobi11.com
1. 本站所有资源来源于用户上传和网络,如有侵权请邮件联系站长!
2. 分享目的仅供大家学习和交流,您必须在下载后24小时内删除!
3. 不得使用于非法商业用途,不得违反国家法律。否则后果自负!
4. 本站提供的源码、模板、插件等等其他资源,都不包含技术服务请大家谅解!
5. 如有链接无法下载、失效或广告,请联系管理员处理!
6. 本站资源售价只是赞助,收取费用仅维持本站的日常运营所需!
7. 如遇到加密压缩包,请使用WINRAR解压,如遇到无法解压的请联系管理员!

波比源码 » Java Notes-10

发表评论

Hi, 如果你对这款模板有疑问,可以跟我联系哦!

联系站长
赞助VIP 享更多特权,建议使用 QQ 登录
喜欢我嘛?喜欢就按“ctrl+D”收藏我吧!♡