class Site:
def __init__(self, id):
self.sid = id
self.variables = {}
self.status = 0 # active = 0, failed = 1
self.init_variables()
self.locks = Lock(self.variables)
def init_variables(self):
for x in range(1, 21):
vid = 'x' + str(x)
if x % 2 == 1:
if self.sid == x % 10 + 1:
self.variables[vid] = Variable(x)
else:
self.variables[vid] = Variable(x)
def is_active(self):
return self.status == 0
def abort(self, transaction):
self.locks.release_read_lock(transaction)
self.locks.release_write_lock(transaction)
def fail(self):
if self.is_active():
self.status = 1
self.locks.release_all_locks()
def read(self, transaction, vid):
if self.variables[vid].status == 0:
if self.locks.hold_read_lock(transaction, vid):
print('Read', vid, '=', self.variables[vid].read_uncommited(transaction), 'at Site', self.sid, 'in', transaction.get_id())
return
else:
ret = None
if not transaction.is_readonly():
ret = self.locks.acquire_read_lock(transaction, vid)
if ret != None:
return ret
print('Read', vid, '=', self.variables[vid].read_commited(transaction), 'at Site', self.sid, 'in', transaction.get_id())
return
def write(self, transaction, vid, val):
try:
ret = None
ret = self.locks.acquire_write_lock(transaction, vid)
if ret != None:
return ret
self.variables[vid].write(transaction, val)
return
except WaitFor:
return [WaitFor.args]
def commit(self, transaction, timestamp):
for vid in self.variables.keys():
if self.locks.hold_write_lock(transaction, vid):
self.variables[vid].commit(timestamp)
self.locks.release_write_lock(transaction)
self.locks.release_read_lock(transaction)
def dump(self):
ret = {}
for vid in self.variables.keys():
ret[vid] = self.variables[vid].read_commitvalue()
return ret
def dumpv(self, vid):
ret = {}
if vid in self.variables:
ret[vid] = self.variables[vid].read_commitvalue()
return ret
def recover(self):
if not self.is_active():
for vid in self.variables.keys():
if self.variables[vid].is_replicated():
self.variables[vid].recover()
self.status = 0
