# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import threading


class AtomicInteger:

    def __init__(self, initial=0):
        # init AtomicInteger，default is 0
        self._value = initial
        self._lock = threading.Lock()

    def get(self):
        with self._lock:
            return self._value

    def set(self, value):
        with self._lock:
            self._value = value

    def get_and_set(self, value):
        with self._lock:
            old_value = self._value
            self._value = value
            return old_value

    def increment_and_get(self):
        with self._lock:
            self._value += 1
            return self._value

    def get_and_increment(self):
        with self._lock:
            old_value = self._value
            self._value += 1
            return old_value

    def decrement_and_get(self):
        with self._lock:
            self._value -= 1
            return self._value

    def get_and_decrement(self):
        with self._lock:
            old_value = self._value
            self._value -= 1
            return old_value

    def compare_and_set(self, expect, update):
        with self._lock:
            if self._value == expect:
                self._value = update
                return True
            return False