HashMap Implementing caching

Package Com.cache;import Java.util.map;import java.util.concurrent.concurrenthashmap;import Org.apache.commons.logging.log;import org.apache.commons.logging.LogFactory; Public classMapcachemanager {PrivateFinalStaticLog log = Logfactory.getlog (Mapcachemanager.class); Private volatile LongUpdateTime =0L;//time to record when updating the cache    Private volatileBoolean Updateflag =true;//When the valve is being updated, false indicates that the cache is currently not updated and is true when the cache is currently being updated    Private volatile StaticMapcachemanager Mapcacheobject;//Cache Instance Objects    Private Staticmap<string, string> cachemap =NewConcurrenthashmap<string, string> ();//Cache Container    PrivateMapcachemanager () { This. Loadcache ();//Load CacheUpdateTime = System.currenttimemillis ();//Cache Update Time    }    /** * use singleton mode to get Cache object instance * * @return*/     Public StaticMapcachemanager getinstance () {if(NULL==mapcacheobject) {synchronized (Mapcachemanager).class) {                if(NULL==mapcacheobject) {Mapcacheobject=NewMapcachemanager (); }            }        }        returnMapcacheobject; }    /** * Load Cache*/    Private voidLoadcache () { This. Updateflag =true;//is updating        /********** data into the CACHEMAP cache **begin * * * * * **/Cachemap.put ("Key1","value1"); Cachemap.put ("Key2","value2"); Cachemap.put ("Key3","Value3"); Cachemap.put ("Key4","Value4"); Cachemap.put ("Key5","Value5"); /********** data into the CACHEMAP cache ***end *******/         This. Updateflag =false;//Update is complete    }    /** * Return Cached Object * * @return*/     PublicMap<string, string>Getmapcache () {LongCurrentTime =System.currenttimemillis (); if( This. Updateflag) {//pre-cache is being updatedLog.info ("cache is Instance ....."); return NULL; }        if( This. Istimeout (currenttime)) {//Reload If the current cache is being updated or the cache is out of timeSynchronized ( This) {                 This.                Reloadcache ();  This. UpdateTime =currenttime; }        }        return  This. Cachemap; }    PrivateBoolean Istimeout (Longcurrenttime) {        return(CurrentTime- This. updatetime) >1000000);//exceeded time limit, timeout    }    /** * Get cache entry Size * @return*/    Private intgetcachesize () {returncachemap.size (); }    /** * Get update time * @return*/    Private LongGetupdatetime () {return  This. UpdateTime; }    /** * GET update flag * @return*/    PrivateBoolean Getupdateflag () {return  This. Updateflag; }    /** Re-loading*/    Private voidReloadcache () { This. Cachemap.clear ();  This.    Loadcache (); }}

Test Example:

Package Com.cache;import Java.util.iterator;import java.util.map;import java.util.set;import Java.util.concurrent.ConcurrentHashMap; Public classCachetest { Public Static voidMain (string[] args) {Mapcachemanager cache=mapcachemanager.getinstance (); Map<string, string> cachemap =NewConcurrenthashmap<string, string>(); Cachemap=Cache.getmapcache (); Set<String>Set=Cachemap.keyset (); Iterator<String> it =Set. iterator ();  while(It.hasnext ()) {String key=It.next (); System. out. println (key+"="+cachemap.Get(key)); }    }}

HashMap Implementing caching