封装BerkeleyDB 2.0

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'''对BerkeleyDB  DB_QUEUE与DB_Recno数据结构的封装  用于优化与提高代码效率'''class BDBQueue(object):"""docstring for Bqueue"""def __init__(self,dbFile=None,cachefilename=None):#创建DBhome = C["DB_PATH"]self.lock = threading.Lock()self.dbenv=bsddb.db.DBEnv()self.dbenv.open(home,bsddb.db.DB_CREATE | bsddb.db.DB_INIT_MPOOL)self.mydb = bsddb.db.DB(self.dbenv)if dbFile:self.dbFile = home + os.sep + dbFileself.mydb.set_re_len(1024)self.mydb.open(self.dbFile,dbtype = bsddb.db.DB_QUEUE, flags = bsddb.db.DB_CREATE)if cachefilename:self.cachefilename = home + os.sep + cachefilenameself.mydb.open(self.cachefilename,dbtype=db.DB_RECNO,flags=db.DB_CREATE)def put(self,item):try:itemStr = json.dumps(item)self.lock.acquire()self.mydb.append(itemStr)self.lock.release()#self.mydb.sync()except Exception, e:raise edef get(self):try:self.lock.acquire()itemStr = self.mydb.consume()self.lock.release()except Exception, e:raise eif itemStr:return json.loads(itemStr[1])def qsize(self):try:self.lock.acquire()dbStat = self.mydb.stat()ndata = dbStat['ndata']except Exception, e:ndata = -1finally:self.lock.release()return ndatadef putdata(self,item):try:db=json.dumps(item)self.lock.acquire()self.mydb.append(db)self.lock.release()except Exception, e:raise edef getOne(self):self.lock.acquire()cur = self.mydb.cursor()val = cur.first()if val:print self.mydb.stat()cur.delete()self.lock.release()return val#清空缓存def sync(self):self.lock.acquire()self.dbenv.memp_sync()self.lock.release()#关闭队列def close(self):"TODO:关闭数据库，队列不再可用"print "CLOSING QUEUE.."self.mydb.close()self.dbenv.close()

#有待进一步优化：对BDB的信息监控，需要实时掌握BDB的详细信息。线程安全问题以及性能提升问题......

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