using counter with while controller

Discussion:

Anton Andreev

2005-08-24 18:28:19 UTC

Hello everybody,

I'm trying to set up a counter to be used with while
controller and i'm having dificulty (my while loop
does not stop). What i did, just before while
controller i have "user variables" where i set
{counter} to 0. In while controller my condition is
${counter}<3 and i have counter (name {counter}, just
like user var) inside the loop which starts from 1 and
increments by 1 till 4. My while loop does not stop.
Please tell me what i'm doing wrong or if i have to
use something else to accomplish what i'm trying to
do.

Thank you,

Anton Andreev

__________________________________________________________
Find your next car at http://autos.yahoo.ca

sebb

2005-08-24 18:49:32 UTC

Permalink

See

http://jakarta.apache.org/jmeter/usermanual/component_reference.html#While_Controller

The While Controller condition needs to return the string "FALSE" or
"false" in order to exit the loop.

${counter}<3

will never be "false"

it will be perhaps "0<3" or "1<3" or "100<3" etc

You need to use a Javascript or Beanshell function to evaluate the
string as an expression.

S

Post by Anton Andreev
Hello everybody,
I'm trying to set up a counter to be used with while
controller and i'm having dificulty (my while loop
does not stop). What i did, just before while
controller i have "user variables" where i set
{counter} to 0. In while controller my condition is
${counter}<3 and i have counter (name {counter}, just
like user var) inside the loop which starts from 1 and
increments by 1 till 4. My while loop does not stop.
Please tell me what i'm doing wrong or if i have to
use something else to accomplish what i'm trying to
do.
Thank you,
Anton Andreev
__________________________________________________________
Find your next car at http://autos.yahoo.ca
---------------------------------------------------------------------

rosiere

2009-12-16 18:22:23 UTC

Permalink

Hello,

I'm also facing problems with while controller, especially with its loop
counter and an embedded foreach controller.

I would like to go through a list of paginated result (like google's search
result), and use a regex to parse every page.

So I first parsed the list page and found the greatest page number (say 2).
Then I defined a while controller with this condition:
${__javaScript( ${i} < ${numPageMaxi} )} (i is a predefined user variable,
initialized to 0)
Then, inside my while controller, I identified HTTP request's format
(parameter) needed to view each page (for example, page 1 needs 0, 50 ;
page 2 needs 50, 100 , and so on ) and I created an HTTP request sampler
with these 2 parameters:

${__javaScript(${i} * 50)} (for lower bound)
${__javaScript(${i} *50 + 50)} (for upper bound)

After the sampler I created a Debug Sampler to view the variables, including
my counter "i".
Afther the debug sampler, I used a BeanShell PostProcessor to increment i:
String i = vars.get("i");
int counter = Integer.parseInt(i);
counter++;
vars.put("i", "" + counter);

My problem is that the http request sampler (that took upperbound and
lowerbound computed from iteration counter i)ran only once with upperbound
to 50 and lowerbound to 0, instead of twice even though I did get the total
number of pages (2) and my PostProcessor ran twice.

In order to fully iterate the pages I had to disable the Debug Sampler
behind the http sampler.

Could you please tell me why my debug sampler interferes with other samplers
and the iteration counter?
Thanks.

Post by sebb
See
http://jakarta.apache.org/jmeter/usermanual/component_reference.html#While_Controller
The While Controller condition needs to return the string "FALSE" or
"false" in order to exit the loop.
${counter}<3
will never be "false"
it will be perhaps "0<3" or "1<3" or "100<3" etc
"You need to use a Javascript or Beanshell function to evaluate the
string as an expression."
S

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rosiere

2009-12-16 18:32:52 UTC

Permalink

Another interference, with foreach controller that followed the http sampler:

I attached a foreach controller, behind the counter incrementing beanshell
postprocessor. The goal is to iterate on "tr" elements of each page, and
send one http request according to each "tr" elements' content.

So if I have 2 pages to go through, and each page contains 50 <tr> elements
I will send 50 http request on each page.

However when running my scenario I found that my outer while controller's
counter "i" was set to <tr> indexes, and set from 1 to 50. Then I lost again
the second page.

So could anyone explain such intereference between controllers even though
they did not seem to share any variable?

Post by rosiere
Hello,
I'm also facing problems with while controller, especially with its loop
counter and an embedded foreach controller.
I would like to go through a list of paginated result (like google's
search result), and use a regex to parse every page.
So I first parsed the list page and found the greatest page number (say 2).
${__javaScript( ${i} < ${numPageMaxi} )} (i is a predefined user variable,
initialized to 0)
Then, inside my while controller, I identified HTTP request's format
(parameter) needed to view each page (for example, page 1 needs 0, 50 ;
page 2 needs 50, 100 , and so on ) and I created an HTTP request sampler
${__javaScript(${i} * 50)} (for lower bound)
${__javaScript(${i} *50 + 50)} (for upper bound)
"
The sampler contained a regex extractor to retrieve and parsed <tr>
elements on the current page. the extractor matched all occurrences of
<tr> according to some rules.
Then the extractor put them into an variable that would represent an array
and would be used by an embedded foreach controller inside the while
controller."
After the sampler I created a Debug Sampler to view the variables,
including my counter "i".
String i = vars.get("i");
int counter = Integer.parseInt(i);
counter++;
vars.put("i", "" + counter);
My problem is that the http request sampler (that took upperbound and
lowerbound computed from iteration counter i)ran only once with upperbound
to 50 and lowerbound to 0, instead of twice even though I did get the
total number of pages (2) and my PostProcessor ran twice.
In order to fully iterate the pages I had to disable the Debug Sampler
behind the http sampler.
Could you please tell me why my debug sampler interferes with other
samplers and the iteration counter?
Thanks.

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Deepak Shetty

2009-12-16 18:37:50 UTC

Permalink

Hi
whats your test look like? Its possible that you put the post processor in
the wrong place? was it a child of the for each instead of the sample or
something?

Also FYI
http://jakarta.apache.org/jmeter/usermanual/component_reference.html#Counter

regards
deepak

Post by rosiere
Hello,
I'm also facing problems with while controller, especially with its loop
counter and an embedded foreach controller.
I would like to go through a list of paginated result (like google's search
result), and use a regex to parse every page.
So I first parsed the list page and found the greatest page number (say 2).
${__javaScript( ${i} < ${numPageMaxi} )} (i is a predefined user variable,
initialized to 0)
Then, inside my while controller, I identified HTTP request's format
(parameter) needed to view each page (for example, page 1 needs 0, 50 ;
page 2 needs 50, 100 , and so on ) and I created an HTTP request sampler
${__javaScript(${i} * 50)} (for lower bound)
${__javaScript(${i} *50 + 50)} (for upper bound)
After the sampler I created a Debug Sampler to view the variables, including
my counter "i".
String i = vars.get("i");
int counter = Integer.parseInt(i);
counter++;
vars.put("i", "" + counter);
My problem is that the http request sampler (that took upperbound and
lowerbound computed from iteration counter i)ran only once with upperbound
to 50 and lowerbound to 0, instead of twice even though I did get the total
number of pages (2) and my PostProcessor ran twice.
In order to fully iterate the pages I had to disable the Debug Sampler
behind the http sampler.
Could you please tell me why my debug sampler interferes with other samplers
and the iteration counter?
Thanks.

Post by sebb
See

http://jakarta.apache.org/jmeter/usermanual/component_reference.html#While_Controller

Post by sebb
The While Controller condition needs to return the string "FALSE" or
"false" in order to exit the loop.
${counter}<3
will never be "false"
it will be perhaps "0<3" or "1<3" or "100<3" etc
"You need to use a Javascript or Beanshell function to evaluate the
string as an expression."
S

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rosiere

2009-12-17 09:01:51 UTC

Permalink

Hello,
I didn't use counter.
This is my last test sequence:
-- http request sampler reading the list of pages
|--> child: regex extractor to extract the total of pages, into a
variable numPageMaxi

-- while controller: ${__javaScript( ${i} < ${numPageMaxi} )}
|--> child 1: http request sampler to turn to the next (it takes
parameters like ${__javaScript(${i} * 50)}, ${__javaScript(${i} * 50 +
50)}, for lower bound and upper bound)

|--> regex extractor to parse <tr> elements into an array:
htmlResponse

|--> child 2: foreach controller on ${htmlResponse}
|--> http request sampler that sends extracted <tr> elements
to a remote server

|--> child 3: BeanShell Post Processor that increments my own counter
variable i, with the following code:
String i = vars.get("i");
int counter = Integer.parseInt(i);
counter++;
vars.put("i", "" + counter);

My BeanShell Postprocessor is a child of the while() controller that runs
over the 2 pages, and not of the foreach() controller that runs over <tr>
elements of each page.

However even if I put the postprocessor in front of foreach(), my scenario
yields still the wrong results (it takes the foreach()'s upper bound as my
${i}'s upper bound.

I will try Counter instead of my own variable incremented by beanshell and
see if it works better.

Post by Deepak Shetty
Hi
whats your test look like? Its possible that you put the post processor in
the wrong place? was it a child of the for each instead of the sample or
something?
Also FYI
http://jakarta.apache.org/jmeter/usermanual/component_reference.html#Counter
regards
deepak

Post by rosiere
Hello,
I'm also facing problems with while controller, especially with its loop
counter and an embedded foreach controller.
I would like to go through a list of paginated result (like google's search
result), and use a regex to parse every page.
So I first parsed the list page and found the greatest page number (say 2).
${__javaScript( ${i} < ${numPageMaxi} )} (i is a predefined user variable,
initialized to 0)
Then, inside my while controller, I identified HTTP request's format
(parameter) needed to view each page (for example, page 1 needs 0, 50 ;
page 2 needs 50, 100 , and so on ) and I created an HTTP request sampler
${__javaScript(${i} * 50)} (for lower bound)
${__javaScript(${i} *50 + 50)} (for upper bound)
After the sampler I created a Debug Sampler to view the variables, including
my counter "i".
String i = vars.get("i");
int counter = Integer.parseInt(i);
counter++;
vars.put("i", "" + counter);
My problem is that the http request sampler (that took upperbound and
lowerbound computed from iteration counter i)ran only once with upperbound
to 50 and lowerbound to 0, instead of twice even though I did get the total
number of pages (2) and my PostProcessor ran twice.
In order to fully iterate the pages I had to disable the Debug Sampler
behind the http sampler.
Could you please tell me why my debug sampler interferes with other samplers
and the iteration counter?
Thanks.

Post by sebb
See

http://jakarta.apache.org/jmeter/usermanual/component_reference.html#While_Controller

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Deepak Shetty

2009-12-17 17:04:17 UTC

Permalink

hi
(one of) Your original question was why your debug sampler seemed to
interfere with your test. The answer is because your post processor is
attached as the child of the while controller, which means it would apply to
every sampler which is a child of the while controller (in your case Child 1
and the debug sampler under the while) and it will also apply to the
children of the for-each controller
Look at the scope rules in JMeter documents.
If you want your post processor to execute only once , you should create a
Test Action controller as the last sample in the While Controller and create
the post processor as the child of the Test Action. (It is probably easier
to just use the Counter)

You are getting incorrect values because your counter variable i is being
incremented too many times.
regards
deepak

Post by rosiere
Hello,
I didn't use counter.
-- http request sampler reading the list of pages
|--> child: regex extractor to extract the total of pages, into a
variable numPageMaxi
-- while controller: ${__javaScript( ${i} < ${numPageMaxi} )}
|--> child 1: http request sampler to turn to the next (it takes
parameters like ${__javaScript(${i} * 50)}, ${__javaScript(${i} * 50 +
50)}, for lower bound and upper bound)
htmlResponse
|--> child 2: foreach controller on ${htmlResponse}
|--> http request sampler that sends extracted <tr> elements
to a remote server
|--> child 3: BeanShell Post Processor that increments my own counter
String i = vars.get("i");
int counter = Integer.parseInt(i);
counter++;
vars.put("i", "" + counter);
My BeanShell Postprocessor is a child of the while() controller that runs
over the 2 pages, and not of the foreach() controller that runs over <tr>
elements of each page.
However even if I put the postprocessor in front of foreach(), my scenario
yields still the wrong results (it takes the foreach()'s upper bound as my
${i}'s upper bound.
I will try Counter instead of my own variable incremented by beanshell and
see if it works better.

Post by Deepak Shetty
Hi
whats your test look like? Its possible that you put the post processor

Post by Deepak Shetty
the wrong place? was it a child of the for each instead of the sample or
something?
Also FYI

http://jakarta.apache.org/jmeter/usermanual/component_reference.html#Counter

Post by Deepak Shetty
regards
deepak

Post by rosiere
Hello,
I'm also facing problems with while controller, especially with its loop
counter and an embedded foreach controller.
I would like to go through a list of paginated result (like google's search
result), and use a regex to parse every page.
So I first parsed the list page and found the greatest page number (say 2).
${__javaScript( ${i} < ${numPageMaxi} )} (i is a predefined user variable,
initialized to 0)
Then, inside my while controller, I identified HTTP request's format
(parameter) needed to view each page (for example, page 1 needs 0, 50 ;
page 2 needs 50, 100 , and so on ) and I created an HTTP request sampler
${__javaScript(${i} * 50)} (for lower bound)
${__javaScript(${i} *50 + 50)} (for upper bound)
After the sampler I created a Debug Sampler to view the variables, including
my counter "i".
String i = vars.get("i");
int counter = Integer.parseInt(i);
counter++;
vars.put("i", "" + counter);
My problem is that the http request sampler (that took upperbound and
lowerbound computed from iteration counter i)ran only once with upperbound
to 50 and lowerbound to 0, instead of twice even though I did get the total
number of pages (2) and my PostProcessor ran twice.
In order to fully iterate the pages I had to disable the Debug Sampler
behind the http sampler.
Could you please tell me why my debug sampler interferes with other samplers
and the iteration counter?
Thanks.

Post by sebb
See

http://jakarta.apache.org/jmeter/usermanual/component_reference.html#While_Controller

Post by Deepak Shetty

Post by rosiere

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Post by Deepak Shetty

Post by rosiere
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sebb

2009-12-17 17:23:41 UTC

Permalink

Post by Deepak Shetty
hi
(one of) Your original question was why your debug sampler seemed to
interfere with your test. The answer is because your post processor is
attached as the child of the while controller, which means it would apply to
every sampler which is a child of the while controller (in your case Child 1
and the debug sampler under the while) and it will also apply to the
children of the for-each controller
Look at the scope rules in JMeter documents.
If you want your post processor to execute only once , you should create a
Test Action controller as the last sample in the While Controller and create
the post processor as the child of the Test Action. (It is probably easier
to just use the Counter)

Or just use a BeanShell Sampler to do the arithmetic.
If you end the script with "return null;" then no sample will be created.

Or you can use the __intSum() function.

Post by Deepak Shetty
You are getting incorrect values because your counter variable i is being
incremented too many times.
regards
deepak

Post by Deepak Shetty
Hi
whats your test look like? Its possible that you put the post processor

Post by Deepak Shetty
the wrong place? was it a child of the for each instead of the sample or
something?
Also FYI

http://jakarta.apache.org/jmeter/usermanual/component_reference.html#Counter

Post by Deepak Shetty
regards
deepak

Post by rosiere
Hello,
I'm also facing problems with while controller, especially with its loop
counter and an embedded foreach controller.
I would like to go through a list of paginated result (like google's search
result), and use a regex to parse every page.
So I first parsed the list page and found the greatest page number (say 2).
${__javaScript( ${i} < ${numPageMaxi} )} (i is a predefined user variable,
initialized to 0)
Then, inside my while controller, I identified HTTP request's format
(parameter) needed to view each page (for example, page 1 needs 0, 50 ;
page 2 needs 50, 100 , and so on ) and I created an HTTP request sampler
${__javaScript(${i} * 50)} (for lower bound)
${__javaScript(${i} *50 + 50)} (for upper bound)
After the sampler I created a Debug Sampler to view the variables, including
my counter "i".
String i = vars.get("i");
int counter = Integer.parseInt(i);
counter++;
vars.put("i", "" + counter);
My problem is that the http request sampler (that took upperbound and
lowerbound computed from iteration counter i)ran only once with upperbound
to 50 and lowerbound to 0, instead of twice even though I did get the total
number of pages (2) and my PostProcessor ran twice.
In order to fully iterate the pages I had to disable the Debug Sampler
behind the http sampler.
Could you please tell me why my debug sampler interferes with other samplers
and the iteration counter?
Thanks.

Post by sebb
See

http://jakarta.apache.org/jmeter/usermanual/component_reference.html#While_Controller

Post by Deepak Shetty

Post by rosiere

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Post by Deepak Shetty

Post by rosiere
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