Chapter 13 signal (III) - example demonstration

Chapter 13 The signal （ 3、 ... and ）- Demonstration of examples

Run the example

Main、Producer and Consumer Each of these three classes has its own Run Method , It is best to run them in their respective terminal windows . Every time it runs , It will display the messages it generates for the log . Once the user responds by providing the input it is waiting for Main class ,Main Of Run Method will terminate the deletion of semaphores . then , The user can view the display of the merged log files of all processes by typing the command

  Do ##class(Semaphore.Util).ShowLog()

Be careful ： All of the following examples assume that all classes are already in “USER” Namespace .

Example 1 - Create and delete semaphores

The simplest example demonstrates the creation and destruction of semaphores . It USES Semaphore.Main class . Do the following ：

1. Open a terminal window .
2. Enter the command ——

Do ##class(Semaphore.Main).Run()

3. This method creates semaphores . If it works , You will see a message “ Enter any character to terminate the run method ”. Press down Enter key . This method displays the initialization value of the semaphore , Delete them , And then quit .
4. Display the log file by issuing a command

Do ##class(Semaphore.Util).ShowLog()

An example of the message displayed in the terminal window following the above steps is as follows

 Examples of messages are as follows 

DHC-APP>Do ##class(Semaphore.Main).Run()
(1) Main Started
(2) New semaphore
(3) Created: "Counter"; Value = 0; Id = 0x0x10000
(4) Semaphore create result: 1
(5) Enter any character to terminate Run method
(6) Final value = 0
(7) Semaphore delete status: 1
(8) Main Finished
(9) Closing Semaphore: Id = 0x10000

 The log output is as follows ：
DHC-APP>  Do ##class(Semaphore.Util).ShowLog()
Message Log: Entries = 9
 
#    $JOB   Sender       Message
1)   24888  Main:        Main Started
2)   24888  Counter:     New semaphore
3)   24888  Counter:     Created: "Counter"; Value = 0; Id = 0x0x10000
4)   24888  Main:        Semaphore create result: 1
5)   24888  Main:        Enter any character to terminate Run method
6)   24888  Main:        Final value = 0
7)   24888  Main:        Semaphore delete status: 1
8)   24888  Main:        Main Finished
9)   24888  Counter:     Closing Semaphore: Id = 0x10000

Example 2—— Create a semaphore and increment it continuously

This example shows that the producer is working , And capture log messages from both processes .

1. Open two separate terminal windows . Call them “A” and “B”.
2. At the window A in , Type the following command , But don't type... At the end ENTER key -

Do ##class(Semaphore.Main).Run()

3. At the window B in , Type the following command , But the same , Do not type at the end of the command ENTER key -

Do ##class(Semaphore.Producer).Run()

4. Now? , At the window A in , Press ENTER key . And then in the window B in , Press ENTER key . This will initiate parallel execution of the two classes . Their respective messages are displayed in their own windows .
5. Producer When the process is complete , close B window .
6. stay A Window , Press ENTER Key to complete Main class . then , Use the following command to display the log -

Do ##class(Semaphore.Util).ShowLog()

For this example , Here is the output

A window

DHC-APP>Do ##class(Semaphore.Main).Run()
(1) Main Started
(2) New semaphore
(3) Created: "Counter"; Value = 0; Id = 0x0x20001
(4) Semaphore create result: 1
(5) Enter any character to terminate Run method
(17) Final value = 30
(18) Semaphore delete status: 1
(19) Main Finished
(20) Closing Semaphore: Id = 0x20001

B window

DHC-APP>Do ##class(Semaphore.Producer).Run()
(6) Producer.1 Started
(7) New semaphore
(8) Open Id = 0x20001
(9) Increment 0x20001 = 0 by 5 wait 10 sec
(10) Increment 0x20001 = 5 by 5 wait 4 sec
(11) Increment 0x20001 = 10 by 3 wait 1 sec
(12) Increment 0x20001 = 13 by 5 wait 9 sec
(13) Increment 0x20001 = 18 by 5 wait 8 sec
(14) Increment 0x20001 = 23 by 4 wait 2 sec
(15) Increment 0x20001 = 27 by 1 wait 8 sec
(16) Increment 0x20001 = 28 by 2 wait 5 sec
(21) Producer.1 Finished
(22) Closing Semaphore: Id = 0x20001

The log shows

DHC-APP>Do ##class(Semaphore.Util).ShowLog()
Message Log: Entries = 22
 
#    $JOB   Sender       Message
1)   21080  Main:        Main Started
2)   21080  Counter:     New semaphore
3)   21080  Counter:     Created: "Counter"; Value = 0; Id = 0x0x20001
4)   21080  Main:        Semaphore create result: 1
5)   21080  Main:        Enter any character to terminate Run method
6)   27724  Producer.1:  Producer.1 Started
7)   27724  Counter:     New semaphore
8)   27724  Producer.1:  Open Id = 0x20001
9)   27724  Producer.1:  Increment 0x20001 = 0 by 5 wait 10 sec
10)  27724  Producer.1:  Increment 0x20001 = 5 by 5 wait 4 sec
11)  27724  Producer.1:  Increment 0x20001 = 10 by 3 wait 1 sec
12)  27724  Producer.1:  Increment 0x20001 = 13 by 5 wait 9 sec
13)  27724  Producer.1:  Increment 0x20001 = 18 by 5 wait 8 sec
14)  27724  Producer.1:  Increment 0x20001 = 23 by 4 wait 2 sec
15)  27724  Producer.1:  Increment 0x20001 = 27 by 1 wait 8 sec
16)  27724  Producer.1:  Increment 0x20001 = 28 by 2 wait 5 sec
17)  21080  Main:        Final value = 30
18)  21080  Main:        Semaphore delete status: 1
19)  21080  Main:        Main Finished
20)  21080  Counter:     Closing Semaphore: Id = 0x20001
21)  27724  Producer.1:  Producer.1 Finished
22)  27724  Counter:     Closing Semaphore: Id = 0x20001

Example 3 - Run all three processes at the same time

This example shows an attempt to increase and decrease the same semaphore in a coherent manner . It uses all three main classes .

1. Open three separate terminal windows . Call them “A”、“B” and “C”.
2. At the window A in , Type the following command , But don't press... At last ENTER key

Do ##class(Semaphore.Main).Run()

3. At the window B in , Type the following command , But the same , Do not press at the end of the command ENTER key -

Do ##class(Semaphore.Producer).Run()

4. At the window C in , Type the following command , But the same , Do not press at the end of the command ENTER key -

Do ##class(Semaphore.Consumer).Run()

5. From the window A Start , Access each window and type ENTER key . This will start Main class , Then there are the other two classes . As mentioned earlier , Each process displays its log messages in its own window .
6. When Producer and Consumer After the process is completed , close B Windows and C window .
7. stay A Window , Press ENTER Key to complete Main class . then , Use the following command to display the log

Do ##class(Semaphore.Util).ShowLog()

Running this example produces output similar to the following ：

window A

DHC-APP>Do ##class(Semaphore.Main).Run()
(1) Main Started
(2) New semaphore
(3) Created: "Counter"; Value = 0; Id = 0x0x40003
(4) Semaphore create result: 1
(5) Enter any character to terminate Run method
<ENTER>
(64) Final value = 0
(65) Semaphore delete status: 1
(66) Main Finished
(67) Closing Semaphore: Id = 0x40003

window B

DHC-APP>Do ##class(Semaphore.Producer).Run()
(6) Producer.1 Started
(7) New semaphore
(8) Open Id = 0x40003
(9) Increment 0x40003 = 0 by 5 wait 8 sec
(20) Increment 0x40003 = 0 by 4 wait 4 sec
(25) Increment 0x40003 = 0 by 3 wait 1 sec
(29) Increment 0x40003 = 0 by 2 wait 10 sec
(36) Increment 0x40003 = 0 by 4 wait 3 sec
(40) Increment 0x40003 = 0 by 5 wait 5 sec
(52) Increment 0x40003 = 0 by 5 wait 6 sec
(58) Increment 0x40003 = 0 by 2 wait 2 sec
(62) Producer.1 Finished
(63) Closing Semaphore: Id = 0x40003

window C

DHC-APP>Do ##class(Semaphore.Consumer).Run()
(10) Consumer.1 Started
(11) New semaphore
(12) Consumer: Open Id = 0x40003
(13) Decrement 0x40003 = 5 by 1 wait 10 sec
(14) WaitCompleted: 0x40003; Amt = 1
(15) Granted
(16) Decrement 0x40003 = 4 by 5 wait 2 sec
(17) WaitCompleted: 0x40003; Amt = 4
(18) Granted
(19) Decrement 0x40003 = 0 by 5 wait 8 sec
(21) WaitCompleted: 0x40003; Amt = 4
(22) Granted
(23) Decrement 0x40003 = 0 by 5 wait 6 sec
(25) WaitCompleted: 0x40003; Amt = 3
(26) Granted
(27) Decrement 0x40003 = 0 by 3 wait 1 sec
(28) Timeout
(30) Decrement 0x40003 = 0 by 4 wait 4 sec
(31) WaitCompleted: 0x40003; Amt = 2
(32) Granted
(33) Decrement 0x40003 = 0 by 2 wait 7 sec
(34) Timeout
(35) Decrement 0x40003 = 0 by 4 wait 9 sec
(37) WaitCompleted: 0x40003; Amt = 4
(38) Granted
(39) Decrement 0x40003 = 0 by 2 wait 5 sec
(41) WaitCompleted: 0x40003; Amt = 2
(42) Granted
(43) Decrement 0x40003 = 3 by 1 wait 3 sec
(44) WaitCompleted: 0x40003; Amt = 1
(45) Granted
(46) Decrement 0x40003 = 2 by 2 wait 10 sec
(47) WaitCompleted: 0x40003; Amt = 2
(48) Granted
(49) Decrement 0x40003 = 0 by 2 wait 4 sec
(50) Timeout
(51) Decrement 0x40003 = 0 by 3 wait 4 sec
(53) WaitCompleted: 0x40003; Amt = 5
(54) Granted
(55) Decrement 0x40003 = 0 by 1 wait 1 sec
(56) Timeout
(57) Decrement 0x40003 = 0 by 3 wait 7 sec
(59) WaitCompleted: 0x40003; Amt = 2
(60) Granted
(61) Consumer.1 Finished
 

The log shows

DHC-APP>Do ##class(Semaphore.Util).ShowLog()
Message Log: Entries = 67
 
#    $JOB   Sender       Message
1)   6412   Main:        Main Started
2)   6412   Counter:     New semaphore
3)   6412   Counter:     Created: "Counter"; Value = 0; Id = 0x0x40003
4)   6412   Main:        Semaphore create result: 1
5)   6412   Main:        Enter any character to terminate Run method
6)   22236  Producer.1:  Producer.1 Started
7)   22236  Counter:     New semaphore
8)   22236  Producer.1:  Open Id = 0x40003
9)   22236  Producer.1:  Increment 0x40003 = 0 by 5 wait 8 sec
10)  20224  Consumer.1:  Consumer.1 Started
11)  20224  Counter:     New semaphore
12)  20224  Consumer.1:  Consumer: Open Id = 0x40003
13)  20224  Consumer.1:  Decrement 0x40003 = 5 by 1 wait 10 sec
14)  20224  Counter:     WaitCompleted: 0x40003; Amt = 1
15)  20224  Consumer.1:  Granted
16)  20224  Consumer.1:  Decrement 0x40003 = 4 by 5 wait 2 sec
17)  20224  Counter:     WaitCompleted: 0x40003; Amt = 4
18)  20224  Consumer.1:  Granted
19)  20224  Consumer.1:  Decrement 0x40003 = 0 by 5 wait 8 sec
20)  22236  Producer.1:  Increment 0x40003 = 0 by 4 wait 4 sec
21)  20224  Counter:     WaitCompleted: 0x40003; Amt = 4
22)  20224  Consumer.1:  Granted
23)  20224  Consumer.1:  Decrement 0x40003 = 0 by 5 wait 6 sec
24)  22236  Producer.1:  Increment 0x40003 = 0 by 3 wait 1 sec
25)  20224  Counter:     WaitCompleted: 0x40003; Amt = 3
26)  20224  Consumer.1:  Granted
27)  20224  Consumer.1:  Decrement 0x40003 = 0 by 3 wait 1 sec
28)  20224  Consumer.1:  Timeout
29)  22236  Producer.1:  Increment 0x40003 = 0 by 2 wait 10 sec
30)  20224  Consumer.1:  Decrement 0x40003 = 0 by 4 wait 4 sec
31)  20224  Counter:     WaitCompleted: 0x40003; Amt = 2
32)  20224  Consumer.1:  Granted
33)  20224  Consumer.1:  Decrement 0x40003 = 0 by 2 wait 7 sec
34)  20224  Consumer.1:  Timeout
35)  20224  Consumer.1:  Decrement 0x40003 = 0 by 4 wait 9 sec
36)  22236  Producer.1:  Increment 0x40003 = 0 by 4 wait 3 sec
37)  20224  Counter:     WaitCompleted: 0x40003; Amt = 4
38)  20224  Consumer.1:  Granted
39)  20224  Consumer.1:  Decrement 0x40003 = 0 by 2 wait 5 sec
40)  22236  Producer.1:  Increment 0x40003 = 0 by 5 wait 5 sec
41)  20224  Counter:     WaitCompleted: 0x40003; Amt = 2
42)  20224  Consumer.1:  Granted
43)  20224  Consumer.1:  Decrement 0x40003 = 3 by 1 wait 3 sec
44)  20224  Counter:     WaitCompleted: 0x40003; Amt = 1
45)  20224  Consumer.1:  Granted
46)  20224  Consumer.1:  Decrement 0x40003 = 2 by 2 wait 10 sec
47)  20224  Counter:     WaitCompleted: 0x40003; Amt = 2
48)  20224  Consumer.1:  Granted
49)  20224  Consumer.1:  Decrement 0x40003 = 0 by 2 wait 4 sec
50)  20224  Consumer.1:  Timeout
51)  20224  Consumer.1:  Decrement 0x40003 = 0 by 3 wait 4 sec
52)  22236  Producer.1:  Increment 0x40003 = 0 by 5 wait 6 sec
53)  20224  Counter:     WaitCompleted: 0x40003; Amt = 5
54)  20224  Consumer.1:  Granted
55)  20224  Consumer.1:  Decrement 0x40003 = 0 by 1 wait 1 sec
56)  20224  Consumer.1:  Timeout
57)  20224  Consumer.1:  Decrement 0x40003 = 0 by 3 wait 7 sec
58)  22236  Producer.1:  Increment 0x40003 = 0 by 2 wait 2 sec
59)  20224  Counter:     WaitCompleted: 0x40003; Amt = 2
60)  20224  Consumer.1:  Granted
61)  20224  Consumer.1:  Consumer.1 Finished
62)  22236  Producer.1:  Producer.1 Finished
63)  22236  Counter:     Closing Semaphore: Id = 0x40003
64)  6412   Main:        Final value = 0
65)  6412   Main:        Semaphore delete status: 1
66)  6412   Main:        Main Finished
67)  6412   Counter:     Closing Semaphore: Id = 0x40003

Other variables

Other variables for this example are possible . Although you can only run one at a time Semaphore.Main, But there is no limit to the number of producers or consumers executing in other windows . Encourage users to try different numbers of consumers and producers in various scenarios , for example

• Run three consumers and one producer , In this way, the semaphore will be larger “ competition ”. With luck , The log will show that two or more consumers have made requests to reduce the semaphore , And it all worked , Because the semaphore value is large enough to satisfy some or all of the two requests .
• You can also use these classes to demonstrate what happens in other processes when you delete semaphores . So , stay Producers or Consumers Runtime , Switch to Main Class is running , Then press ENTER. In the process of completing the processing ,Main Class will delete semaphores ,Producer or Consumer Of OREF Will no longer be valid . The next attempt will result in an error .
• By changing the name of the semaphore to something that looks like the global name , Semaphores can be mapped to, for example ECP Different instances on the system .