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  • 那么问题来了,这个sleep时间到底设置多少合适呢?...这个时候我们可以用wait_activity的语法,等到你想点击的页面activity出现了,再点击,可以有效的节省时间。wait_activity1.查看源码def wait_activit...

    前言

    在启动app的时候,如果直接做下一步点击操作,经常会报错,于是我们会在启动完成的时候加sleep。

    那么问题来了,这个sleep时间到底设置多少合适呢?设置长了,就浪费时间,设置短了,就会找不到元素报错了。

    这个时候我们可以用wait_activity的语法,等到你想点击的页面activity出现了,再点击,可以有效的节省时间。

    wait_activity

    1.查看源码

    def wait_activity(self, activity, timeout, interval=1):

    """Wait for an activity: block until target activity presents

    or time out.

    This is an Android-only method.

    :Agrs:

    - activity - target activity

    - timeout - max wait time, in seconds

    - interval - sleep interval between retries, in seconds

    """

    try:

    WebDriverWait(self, timeout, interval).until(

    lambda d: d.current_activity == activity)

    return True

    except TimeoutException:

    return False

    2.解释说明:

    wait_activity(self, activity, timeout, interval=1):

    等待指定的activity出现直到超时,interval为扫描间隔1秒

    即每隔几秒获取一次当前的activity

    android特有的

    返回的True 或 False

    :Agrs:

    - activity - 需等待的目标 activity

    - timeout - 最大超时时间,单位是s

    - interval - 循环查询时间

    用法:driver.wait_activity(‘.activity.xxx’,5,2)

    获取current_activity

    1.打开app后,先sleep10秒,等app完全启动完成进入主页面,然后获取当前界面的activity

    # coding:utf-8

    from appium import webdriver

    from time import sleep

    desired_caps = {

    'platformName': 'Android',

    'deviceName': '127.0.0.1:62001',

    'platformVersion': '4.4.2',

    'appPackage': 'com.baidu.yuedu',

    'appActivity': 'com.baidu.yuedu.splash.SplashActivity'

    }

    driver = webdriver.Remote('http://127.0.0.1:4723/wd/hub', desired_caps)

    sleep(10)

    # 获取当前界面activity

    ac = driver.current_activity

    print(ac)

    2.运行结果:

    76828963db8eb9eea2fb3480fdda6b45.png

    等待activity

    1.用sleep太浪费时间了,并且不知道什么时候能启动完成,所以尽量不用sleep

    2.上一步已经获取当主页面的activity了,那就可以用wait_activity等它出现了,再做下一步的点击操作

    8c22c4fd93c7cbc4796553e1d71e39d1.png

    3.参考代码

    # coding:utf-8

    from appium import webdriver

    from time import sleep

    desired_caps = {

    'platformName': 'Android',

    'deviceName': '127.0.0.1:62001',

    'platformVersion': '4.4.2',

    'appPackage': 'com.baidu.yuedu',

    'appActivity': 'com.baidu.yuedu.splash.SplashActivity'

    }

    driver = webdriver.Remote('http://127.0.0.1:4723/wd/hub', desired_caps)

    # sleep(10) # 不用sleep

    # 获取当前界面activity

    ac = driver.current_activity

    print(ac)

    # 等主页面activity出现,30秒内

    driver.wait_activity(".base.ui.MainActivity", 30)

    # 点知道了

    driver.find_element_by_id("com.baidu.yuedu:id/positive").click()

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  • Oracle Wait Events: Wait for scn ackwait for scn ack 是在RAC环境中可能常见的一个等待事件,意思是等待跨实例的SCN应答。Top 5 Timed Events Avg %Totalr~~~~~~~~~~~~~~~~~~ ...

    Oracle Wait Events: Wait for scn ack

    6ee5639a40442445944d63b514b2dd02.png

    wait for scn ack 是在RAC环境中可能常见的一个等待事件,意思是等待跨实例的SCN应答。Top 5 Timed Events                                        Avg %Totalr

    ~~~~~~~~~~~~~~~~~~                                        wait  Call

    Event                                Waits    Time (s)  (ms)  Time Wait Class

    ------------------------------ ------------ ----------- ------ ------ ----------

    CPU time                                          1,751          47.8

    db file sequential read            318,634        902      3  24.7  User I/O

    log file sync                      186,536        404      2  11.0    Commit

    db file scattered read              101,049        333      3    9.1  User I/O

    wait for scn ack                    150,087        295      2    8.1      Other

    -------------------------------------------------------------

    ACK (ACKnowledgment) 的意思是:TCP首部中的确认标志,对已接受到的TCP报文进行确认。Acknowledge Character,就是确认字符。在数字通信协议中,如果接受方成功的接收到数据,那么会回复一个ACK信号。通常ACK信号有自己固定的格式,长度大小,由接受方回复给发送方。其格式取决于采取的网络协议。当发送方接收到ACK信号时,就可以发送下一个数据。如果发送方没有收到信号,那么发送方可能会重发当前数据包,也可能停止传送数据。具体情况取决于所采用的网络协议。ACK信号通常是一个ASCII字符,不同的协议中ACK信号都不一样。

    一段英文解释:ACK - ACK signal,In some digital communication protocols, ACK is the name of a signal that data has been received successfully (for example, with an acceptable number of errors). The ACK signal is sent by the receiving station (destination) back to the sending station (source) after the receipt of a recognizable block of data of specific size. In order to be recognizable, the data block must conform to the protocol in use. When the source receives the ACK signal from the destination, it transmits the next block of data. If the source fails to receive the ACK signal, it either repeats the block of data or else ceases transmission, depending on the protocol.

    The ACK signal is usually an ASCII character that is reserved for that purpose. In some protocols, there are various ACK signals that indicate the successful reception and recognition of specific commands, such as power-down or standby.

    但是由于等待事件 'wait for scn ack' 不能给出足够的信息量度LGWR发出BOC信息以及收到ACK信息的时间。在10.2.0.5及11gR2中,将增加了一个新的统计信息'redo write broadcast ack time'用于辅助的时间统计。

    BOC是Oracle的SCN传递算法之一,即Broadcast on Commit。在Oracle9i中,缺省的SCN传播算法是lamport算法,SCN在实例间传递是通过GCS MESSAGE来传递的,因此会存在一定的延时,在某些情况下,如果不同实例的SCN不能及时传递,多个节点之间就可能看到不同的数据,导致逻辑错误,Oracle可以通过一个参数来控制SCN的传播延时,这个参数是MAX_COMMIT_PROPAGATION_DELAY,在Oracle9i及Oracle10gR1中,其缺省值是700(7秒),确保SCN传播不得超过7秒,但是7秒已经是一个很长的时间参数。一般每3秒LCK进程就会进行一次跨实例数据交换。如果将该参数设置为0~99,就会禁用Lamport方式,使用BOC方式进行SCN同步。

    从Oracle10gR2开始,BOC是缺省的SCN传播机制,同时参数_immediate_commit_propagation 设置为TRUE,以为着由Commit引起的SCN会立即传播,排除延时:SQL> SET linesize 120

    SQL> COL name for a30

    SQL> COL value for a20

    SQL> COL describ for a60

    SQL> SELECT x.ksppinm NAME, y.ksppstvl VALUE, x.ksppdesc describ

    2    FROM SYS.x$ksppi x, SYS.x$ksppcv y

    3  WHERE x.indx = y.indx AND x.ksppinm LIKE '%&par%'

    /  4

    Enter value for par: _commit

    old  3:  WHERE x.indx = y.indx AND x.ksppinm LIKE '%&par%'

    new  3:  WHERE x.indx = y.indx AND x.ksppinm LIKE '%max_commit%'

    NAME                          VALUE                DESCRIB

    ------------------------------ -------------------- ------------------------------------------------------------

    max_commit_propagation_delay  0                    Max age of new snapshot in .01 seconds

    _immediate_commit_propagation  TRUE                if TRUE, propagate commit SCN immediately

    By eygle on 2009-02-22 11:52 |

    Comments (2) |

    Internal | 2203 |

    2 Comments

    可以继续深入讲解下,哪些scn被传播,整个过程运行概况

    GoldenGate在RAC做数据复制就受这个SCN传播影响

    展开全文
  • Unit 6 - A Day's Wait Ernest Hemingway's story is about an incident that happens between a father and his son. The small boy's misunderstanding of the difference in measuring temperature on a ...

    Unit 6 - A Day's Wait

    Ernest Hemingway's story is about an incident that happens between a father and his son. The small boy's misunderstanding of the difference in measuring temperature on a Fahrenheit and a Celsius Scale causes him to believe that he is dying of a high fever. However, the father doesn't realize it until very late that day……

    A Day's Wait

    Ernest Hemingway

    He came into the room to shut the windows while we were still in bed and I saw he looked ill. He was shivering, his face was white, and he walked slowly as though it ached to move.

    "What's the matter, Schatz?"

    "I've got a headache."

    "You better go back to bed."

    "No. I'm all right."

    "You go to bed. I'll see you when I'm dressed."

    But when I came downstairs he was dressed, sitting by the fire, looking a very sick and miserable boy of nine years. When I put my hand on his forehead I knew he had a fever.

    "You go up to bed," I said, "You're sick."

    "I'm all right," he said.

    When the doctor came he took the boy's temperature.

    "What's is it?" I asked him.

    "One hundred and two."

    Downstairs, the doctor left three different medicines in different colored capsules with instruction for giving them. One was to bring down the fever, another a purgative, the third to overcome an acid condition. The germs of influenza can only exist in an acid condition, he explained. He seemed to know all about influenza and said there was nothing to worry about if the fever did not go above one hundred and four degrees. This was a light epidemic of flu and there was no danger if you avoided pneumonia.

    Back in the room I wrote the boy's temperature down and made a note of the time to give the various capsules.

    "Do you want me to read to you?"

    "All right. If you want to, " said the boy. His face was very white and there were dark areas under his eyes. He lay still in the bed and seemed very detached from what was going on.

    I read aloud from Howard Pyle's Book of pirates; but I could see he was not following what I was reading.

    "How do you feel, Schatz?" I asked him.

    "Just the same, so far," he said.

    I sat at the foot of the bed and read to myself while I waited for it to be time to give another capsule. It would have been natural for him to go to sleep, but when I looked up he was looking at the foot of the bed, looking very strangely.

    "Why don't you try to sleep? I'll make you up for the medicine."

    "I'd rather stay awake."

    After a while he said to me, "You don't have to stay in here with me, Papa, if it bothers you."

    "It doesn't bother me."

    "No, I mean you don't have to stay if it's going to bother you."

    I though perhaps he was a little lightheaded and after giving him the prescribed capsules at eleven o'clock I went out for a while. It was a bright, cold day, the ground covered with a sleet that had frozen so that it seemed as if all the bare trees, the bushes, the cut brush and all the grass and the bare ground had been varnished with ice, I took the young Irish setter for a walk up the road and along a frozen creek, but it was difficult to stand or walk on the glassy surface and the red dog slipped and slithered and I fell twice, hard, once dropping my gun and having it slide away over the ice.

    We flushed a covey of quail under a high clay bank with overhanging brush and I killed two as they went out of sight over the top of the blank. Some of the covey lit in trees, but most of them scattered into brush piles and it was necessary to jump on the ice-coated mounds of brush several times before they would flush. Coming out while you were poised unsteadily on the icy, springy brush they made difficult shooting and I killed two, missed five, and started back pleased to have found a covey close to the house and happy there were so many left to find on another day.

    At the house they said the boy had refused to let anyone come into the room.

    "You can't come in," he said. "You mustn't get what I have."

    I went up to him and found him in exactly the position I had left him, white-faced, but with the tops of his cheeks flushed by the fever, staring still, as he had stared, at the foot of the bed.

    I took his temperature.

    "What is it?"

    "Something like a hundred," I said. It was one hundred and two and four tenths.

    "It was a hundred and two," he said.

    "Who said so?"

    "The doctor."

    "Your temperature is all right," I said. "It's nothing to worry about."

    "I don't worry," he said, "but I can't keep from thinking."

    "Don't think," I said. "Just take it easy."

    "I'm taking it easy," he said and looked straight ahead, He was evidently holding tight onto himself about something.

    "Take this with water."

    "Do you think it will do any good?"

    "Of course it will."

    I sat down and opened the Pirate book and commenced to read, but I could see he was not following, so I stooped.

    "About what time do you think I'm going to die?" he asked.

    "What?"

    "About how long will it be before I die?"

    "You aren't going die. What's the matter with you? "

    "Oh, yes, I am, I heard him say a hundred and two."

    "People don't die with a fever of one hundred and two. That's a silly way to talk."

    "I know they do. At school in France the boys told me you can't live with forty-four degrees. I've got a hundred and two."

    He had been waiting to die all day, ever since nine o'clock in the morning.

    "You poor Schatz," I said. "Poor old Schatz. It's like miles and kilometers. You aren't going to die. That's different thermometer. On that thermometer thirty-seven is normal. On this kind it's ninety-eight."

    "Are you sure?"

    "Absolutely," I said, "It's like miles and kilometers. You know, like how many kilometers we make when we do seventy miles in the car?"

    "Oh," he said.

    But his gaze at the foot of the bed relaxed slowly. The hold over himself relaxed too, finally, and the next day it was very slack and he cried very easily at little things that were of no importance.

    参考译文——一天的等待

    欧内思特·海明威

    他走进我们房间关窗户的时候,我们还没起床。我见他一幅病容,全身哆嗦,脸色苍白,步履艰难,好像每迈一步都会引起疼痛。

    “怎么啦,宝贝?”

    “我头痛。”

    “你最好再回床上去躺一会儿。”

    “不,我没事儿。”

    “你先去躺一会儿,我穿好衣服就去看你。”

    可是当我下楼时,他已经穿好了衣服,坐在炉边。他才9岁啊,看上去病得很厉害,一幅招人可怜的样子。我用手摸摸他的额头,知道他发烧了。

    “你到楼上去躺着,”我说,“你病了。”

    “我没病,”他说。

    医生来后,量了孩子的体温。

    “多少度?”我问医生。

    “102度。”

    下楼后,医生留下三种药,胶囊的颜色各不相同,并下了医嘱。第一种是退烧药,另一种是泻药,第三种能解酸。他解释说,流感细菌只生存于酸性环境中。他好像对流感很有研究,还说,不烧到104度就不用担心。这是轻度流感,只要不引起肺炎没有什么危险。

    我回到房里记下了孩子的体温,还记下了各种药物的服用时间。

    “要不要给你念点什么听啊?”

    “好吧,你要是想念就念吧,”孩子说。他的脸色十分苍白,眼窝下方有黑晕。躺在床上一动也不动,看上去对身边发生的一切都没有兴致。

    我给他念霍华德·派尔的《海盗故事》,但看得出他并没有听。

    “你感觉怎么样,宝贝?”我问他。

    “到目前为止,还是老样子。”他说。

    我坐在床脚。干脆自顾自地读了起来,我得等时间一到再给他服另一种药。按理说,他该睡过去了。但是,当我抬起头时,却看到他两眼盯着床脚,神情异常。

    “你为什么不睡一会儿呢?到吃药的时候我会叫醒你的。”

    “我宁愿醒着。”

    过了一会,他对我说:“你不必在这里陪我,爸爸,要是这事让你烦恼的话。”

    “没什么可烦恼的。”

    “不,我是说要是这事将会给你带来烦恼的话,你就不必在这里陪我。”

    我想,他大概有些神志不清了。我按规定十一点时给他服了药。随后,便出去了一会儿。

    那天天气很晴朗,也很寒冷,地面上覆盖的一层冻雨已经结成了冰。那光秃秃的落叶树木,那灌木丛,还有砍下的树枝,以及所有的草坪和空地都像涂了一层冰。我带着那条幼小的爱尔兰猎犬出去逛逛。我们走上公路,又沿着一条冰封的小溪往前走。但在那玻璃般光滑的冰面上,无论是站立还是行走,都很困难。红毛狗一路上连哧溜带滑,我自己也重重地摔倒了两次,其中一次连猎枪也摔掉了,在冰上滑出去老远。

    高高的土堤上长着倒垂下来的灌木丛,我们从灌木丛下面哄起一群鹌鹑。就在它们快要越过堤岸飞离视野时我击落了两只。有几只鹌鹑落在了树上,但大部分飞散了,钻进了灌木丛。它们得在裹了一层冰的树冠上跳上几跳,才能起飞。你在这些又滑又颤的树丛上摇摇晃晃尚未立稳,它们却飞了出来,使你很难瞄准。但我还是击落了两只,另有五只没有击中。动身返回时,我心情很愉快,因为在离家不远的地方又发现了一群鹌鹑,猎获了两只,还剩下许多,改日可再来猎取。

    回到家里听说孩子不让任何人进他的房间。

    “你们不能进来,”他说,“你们绝不能染上我这种病。”

    我来到他身边,发现他还像我离开时那样躺着,脸色苍白,但脸颊上烧出了两朵红晕,眼睛依然一动不动地盯着床脚。

    我给他量了体温。

    “多少度?”

    “大约100度,”我说。实际上是102.4度。

    “原先是102度,”他说。

    “谁说的?”

    “医生。”

    “你的体温没啥问题,”我说,“根本不用担心。”

    “我倒不担心,”他说,“可我就是不能不想。”

    “不要想了,”我说。“放心好了。”

    “我倒没有什么不放心的,”他说着,眼睛直盯着前方。显然,他有什么心事,但却极力克制着不说。

    “把这个用水吞下去。”

    “你觉得有用吗?”

    “当然有用。”

    我坐下来,又打开了《海盗故事》,开始念给他听。但看得出他没有听,于是,我就不念了。

    “你认为我会什么时候死呢?”他问道。

    “你说什么?”

    “你看我还能活多久?”

    “你不会死的。你怎么啦?”

    “哦,我会死的。我听见他说102度了。”

    “人烧到102度是不会死的。你这是在说傻话呢。”

    “会的。在法国上学的时候,我就听说,烧到44度就不能活了。我已经到102度了。”

    原来从上午9点钟起,他一整天都在等死啊。

    “我可怜的宝贝,”我说,“这就像英里和公里的区别一样。知道吗?就像我们开车开了70英里能折合成多少公里一样。”

    “噢,”他恍然大悟。

    他那凝视床脚的目光渐渐放松了,心里的紧张状态也终于缓解了,第二天,他一点儿也打不起精神来,这还不说,为了一点点小事他还动不动就哭鼻子。

    参考资料:

    1. http://www.kekenet.com/menu/200602/3930.shtml

    2. https://www.zww.cn/zuowen/yingyu/meiwen/1/25770.htm

    展开全文
  • 3.3 然后,Thread-1消费端线程抢到了执行权,在原来wait()方法的地方醒过来,执行wait()方法后面的代码System.out.println(Thread.currentThread().getName() + "消费端:醒过来了。。。");然后继续while循环判断...

    1、写一个包子生产消费案例:一次生产或消费一个包子,有包子就消费,没有就生产。(部分代码参考传智播客刘意2015Java基础视频讲义)

    1.1 写一个Baozi.class,包含main()方法,用来测试

    packagecom.oy.demo3;/** 包子生产消费案例:一次生产或消费一个包子,有包子就消费,没有就生产。*/

    public classBaozi {//默认是flag,表示没有包子,需要生产线程来生产包子;如果是true,说明有包子,需要消费端来消费包子。

    public booleanflag;//计数,当前在生产或消费第n个包子

    public int count = 0;public static voidmain(String[] args) {//创建共享对象

    Baozi s = newBaozi();//在外界把共享对象创建出来,通过构造方法传递给其他的类。这样st、gt1、gt2就共享s对象。

    SetThread st = newSetThread(s);

    GetThread gt1= newGetThread(s);

    GetThread gt2= newGetThread(s);//线程类

    Thread t1 = newThread(st);

    Thread t2= newThread(gt1);

    Thread t3= newThread(gt2);//启动线程

    t1.start();

    t2.start();

    t3.start();

    }

    }

    1.2 生产包子的线程类 SetThread.class

    packagecom.oy.demo3;public class SetThread implementsRunnable {privateBaozi s;publicSetThread(Baozi s) {this.s =s;

    }

    @Overridepublic voidrun() {while (true) {synchronized(s) {//判断有没有

    if (s.flag) { //生产端,有就等待

    try{

    System.out.println("生产端:等待。。。");

    s.wait();//等待,并且立即释放锁。将来醒过来的时候,是从这里醒过来的

    System.out.println("生产端:醒过来了。。。");

    }catch(InterruptedException e) {

    e.printStackTrace();

    }

    }//开始生产

    s.count++;

    System.out.println("生产第" + s.count + "包子。。。");//生产完后,修改标记为true

    s.flag = true;//唤醒线程

    s.notifyAll();

    System.out.println("==========开始抢CPU的执行权==========");

    }

    }

    }

    }

    1.3 消费包子的线程类 GetThread.class

    packagecom.oy.demo3;public class GetThread implementsRunnable {privateBaozi s;publicGetThread(Baozi s) {this.s =s;

    }

    @Overridepublic voidrun() {while (true) {synchronized(s) {while (!s.flag) { //消费端,没有就等待

    try{

    System.out.println(Thread.currentThread().getName()+ "消费端:等待。。。");

    s.wait();//等待,并且立即释放锁。将来醒过来的时候,是从这里醒过来的

    System.out.println(Thread.currentThread().getName() + "消费端:醒过来了。。。");

    }catch(InterruptedException e) {

    e.printStackTrace();

    }

    }//开始消费

    System.out.println(Thread.currentThread().getName() + "消费第" + s.count + "个包子");//消费完了,修改标记为false

    s.flag = false;//唤醒线程

    s.notifyAll();

    System.out.println("==========开始抢CPU的执行权==========");

    }

    }

    }

    }

    2、测试结果(只选择了控制台打印的部分结果):

    ==========开始抢CPU的执行权==========

    生产端:等待。。。

    Thread-2消费端:醒过来了。。。

    Thread-2消费第6806个包子

    ==========开始抢CPU的执行权==========

    Thread-2消费端:等待。。。

    Thread-1消费端:醒过来了。。。

    Thread-1消费端:等待。。。

    生产端:醒过来了。。。

    生产第6807包子。。。

    ==========开始抢CPU的执行权==========

    3、对测试结果的分析:

    3.1 首先明确,生产端开启了一个线程,消费端开启了两个线程。

    3.2 Thread-2消费第6806个包子,然后唤醒等待的线程;然后3个线程开始抢CPU的执行权,Thread-2消费端线程抢到了,但是此时没有包子了,所以等待;

    3.3 然后,Thread-1消费端线程抢到了执行权,在原来wait()方法的地方醒过来,执行wait()方法后面的代码System.out.println(Thread.currentThread().getName() + "消费端:醒过来了。。。");然后继续while循环判断,由于此时没有包子,所以等待。如果把while改成if,就不会判断是否有包子,之间执行后面的代码消费包子,此时并没有包子了,这就产生了错误(同一个包子被消费了两次)。

    3.4 综上所述:wait()方法套在while循环中,线程下次醒过来后会继续进行循环,判断条件是否满足,满足就重新等待。

    3.5 由于生产端只开启了一个线程,所以将wait()方法套在if代码块中也是可以的,当然使用while也可以。

    展开全文
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