Is This a Global Versus Local Variable Problem?

I intend to use a variable (myselector) with a text value (e.g. roses, Big Sur, Pacific Grove, night, etc.) for the sort criteria of my photography list. Selection of a tab from a Tabbed Panel will appropriately define the variable and the selected thumbnails will display in the Content Panel.
The variable "myselector" is defined in the head section; a function for each tab of the Tabbed Panel will redefine the variable per the selected tab. Within the function, I am not using "var" to call the variable. Though the variable "myselector" should be global, the changes to its value are discarded when the function closes. This indicates that it is functioning like a local variable in the function. After a bit of reading, I've not found the cause of the global/local discrepancy or a fix for it.
Diagnosis History - I generated a simplified code. Variable "myselector" is defined as "abcd"; function "myfilter" is called by onclick of the text "button" and changes "myselector" to "efgh". At the end of the file, I used "document.write (myselector) to output the "myselector" value. The script follows.
The end value of "myselector" does not change. However, when I add "document.write (myselector)" to the function, then the changed value is displayed.
I ask someone to explain what I am doing incorrectly or, at least, guide me to a solution. I thank you for your assistance.
Scott
<script type="text/javascript">
var myselector="abcd";
function MM_callJS(jsStr) { //v2.0
return eval(jsStr)
</script>
</head>
<body>
<div id=text>
<p onclick="MM_callJS('myfilter();')">Button</p>
<script type="text/javascript">
function myfilter() {myselector="efgh"; }
</script>
<script type="text/javascript">
document.write (myselector);
</script>
</div>

Dear Ben:
I thank youfor your patience. This includes the script using Insert - Syntax Highlighting - Java.
The coding needs a lot of clean up but I want it to work, first.
Scott
<script src="SpryAssets/xpath.js" type="text/javascript"></script>
<script src="SpryAssets/SpryData.js" type="text/javascript"></script>
<script src="SpryAssets/SpryTabbedPanels.js" type="text/javascript"></script>
<script type="text/javascript">
var dsphotodata = new Spry.Data.XMLDataSet("EM_photo.xml", "/gallery");
</script>
<script type = "text/javascript">
function MM_callJS(jsStr) { //v2.0
return eval(jsStr)
</script>
<script type="text/javascript">
var dsphoto = new Spry.Data.XMLDataSet("EM_photo.xml", "/gallery/photos/photo");
dsphoto.filter(subjectfilter);
var myselector;
</script>
<link href="SpryAssets/SpryTabbedPanels.css" rel="stylesheet" type="text/css" />
</head>
<body>
This is a test of Scott's efforts to program his website.
<br />
<br />
<div id="TabbedPanels1" class="TabbedPanels">
<ul class="TabbedPanelsTabGroup">
    <li class="TabbedPanelsTab" tabindex="0" onclick="MM_callJS('{myselector=\'animal\'}; subjectfilter(); dsphoto.filter(subjectfilter); ')">Tab 1</li>
    <li class="TabbedPanelsTab" tabindex="0" onfocus="MM_callJS('myselector=\"pgbeach\" subjectfilter(); dsphoto.filter(subjectfilter); ')">Tab 2</li>
    <li class="TabbedPanelsTab" tabindex="0">Blank</li>
</ul>
<div class="TabbedPanelsContentGroup">
    <div class="TabbedPanelsContent" >Content 1
      <br />
<br />
<script> {document.write (myselector)} </script>
      <br />
      <div spry:region="dsphoto dsphotodata"> <img src="{dsphotodata::thumbnail/@base}{@thumbpath}" width = {@thumbwidth}px height = {@thumbheight}px spry:repeat="dsphoto" onclick="dsphoto.setCurrentRow('{ds_RowID}');" /></div>
    </div>
    <div class="TabbedPanelsContent">Content 2
      <script> {document.write (myselector)} </script>
      <br />
      <div spry:region="dsphoto dsphotodata"> <img src="{dsphotodata::thumbnail/@base}{@thumbpath}" width = {@thumbwidth}px height = {@thumbheight}px spry:repeat="dsphoto" onclick="dsphoto.setCurrentRow('{ds_RowID}');" /></div>
    </div>
    <div class="TabbedPanelsContent">Content 3 <script> {document.write (myselector)} </script><br />
<div spry:region="dsphoto dsphotodata"> <img src="{dsphotodata::thumbnail/@base}{@thumbpath}" width = {@thumbwidth}px height = {@thumbheight}px spry:repeat="dsphoto" onclick="dsphoto.setCurrentRow('{ds_RowID}');" /></div>
</div>
</div>
</div>
<div id="Selected_Photo" spry:detailregion = "dsphoto dsphotodata" >
<img src="Photo-Thumbnails/{@thumbpath}" width = {@thumbwidth}px height = {@thumbheight}px /><br />
<img src="Photo-Email/{@path}" width = {@width}px height = {@height}px />
</div>
<script type="text/javascript">
var subjectfilter = function(dataSet, row, rowNumber, criteria) { if (row["@subject"].search (myselector) != -1) return row; return null; };

</script>

Similar Messages

Global and Local Variable

Hi Gurus, I was unable to see where I can define local and global variables? I see that help.sap.com documentation but where do I create. All variables that I create, are global because, they are visible to all and they all can use it? Any help would be greatly appreciated.

As far as I know, Variables are re-usable objects that are not dependent upon InfoProvider. When I look at this link
http://help.sap.com/saphelp_nw04/helpdata/en/5c/8db07d555411d189660000e829fbbd/frameset.htm
it talks about Global and Local variable? Is this different than what we use in Query Designer?

Local variable problem

I am making an application that takes an apartment number and number of occupants in that apartment and then displays a number of statistics. So far I haven't had much problem
except on a what is probably a very simple problem.
I have two buttons, and when "store" is clicked the info in the textboxes is input to an array.
My problem is with the next button, "quit", this is where all the info is supposed to be displayed.
All my variables that I need from "store" are local and are recognized in " the if statement in quit. Ive tried declaring them outside of the if statement, but it hasn't been working.
{code}
public void actionPerformed(ActionEvent event)
               Object source = event.getSource();
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                    Integer aptNo = Integer.parseInt(input1.getText());
                    Integer occup = Integer.parseInt(input2.getText());
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                    else
                         occupants[aptNo] = occup;
                         input1.setText("");
                         input2.setText("");
                         JOptionPane.showMessageDialog(null, input.getNumber(occupants));
               if (source == quit)
               // I need the variables aptNo and occup in here to put into my methods for output, but I don't know how to get them.
{code}

EmmCeeVee wrote:
Thank you for all of the responses, it really helps me out.
Obviously my knowledge of local variables is hurting as I switched it around as your said and declared the aptNo and occup outside of the if's.
All I need is for the quit button to look at the array ( which has just been modified by the sotre button) and output a bunch of results.
Heres where im at:Your problem is of scope of the variables.
Here whatever variable you defined in actionPerformed they are local for that method (they are out of scope when the method is finished/called again), Upon this, the actionPerformed is called twice one for store and another time for quit. So you cant expect the value stored at store should be there still when you all quit
If you want those values available on both the actions then make them a class level variables.
Below is a sample program, might help you.
class Employee
     String empName = null;
     int empNo;
     Employee(String eName,int eNmbr)
          this.empName = eName;
          this.empNo = eNmbr;
class CheckVariableScope
        Employee empOb; // Here
     int eNo;
     String eName = null;
     public void checkScope(String action)
                //Instead of defining Employee reference variable, eNo and eName in checkScope method, define it @ class level.
                // in your case they are Apartment input, Integer aptNo and Integer occup
                 // like above i did.
                 // If i comment the class level variable and uncomment method variable, this program also give the same error.
          //Employee empOb;
          //int eNo;
          //String eName = null;
          if (action.equals("Store") )
                    eNo = 10;
                    eName = "Bob";
                    empOb = new Employee(eName, eNo);
                    System.out.println("The eName is : "+empOb.empName+" , empNo is : "+empOb.empNo);
               if (action.equals("quit"))
                    System.out.println(" eNO from Object is : "+empOb.empNo);
                    System.out.println(eNo); //Error: may not have been intitialized
     public static void main (String st[])
          CheckVariableScope ob = new CheckVariableScope();
          ob.checkScope("Store");
          ob.checkScope("quit");
}

Shall I use global or local variables for my program?

Hello,
1) I am using 2 while loops in parallele. One 50 ms timed and the other one 1000 ms. The 50 ms one gets data from a sensor. I want to display that data every 1000ms in the 1000 ms loop. I have used global variables to do that. Should I better use local variables?
2) This question deals with the VI I have attached
a) Shall I initialise the " Quitter programme " global variable in the main VI aswell ? Or is what I have done enough?
b)
I want the sequence to continue ( finishes the last sequence and goes back to the first one without any delay if possible ) until the user presses Quit. I am concerned about the " wait until " icon of the exterior main while loop ( set to be 250 ms at the moment ). This time, 250 ms, is the time it takes between the end of the last sequence and the beginning of the first sequence? Is that right? Once u start the first sequence, the while loop doesn’t do anything until the end of the last sequence ( my 3 sequences can take several minutes ) ?
Hope I am clear… lol
Don’t hesitate to ask any questions if not clear enough
thanks a lot,
David
Attachments:
Example1.zip ‏28 KB

Bonjour Marc. You will definitely have a race condition because you are writing to the global in a parallel loop. You could click the stop button in the quitter program, then before it is read in the main loop, the lower loop writes a false to it, and your click is lost. Why do you want a separate quitter program? You may have a good reason but it isn't clear here. I would not use globals or locals for this, just put your stop button on the main vi. You already have one, so why do you want another one in another vi? If you must do it this way, eliminate both lower loops. They are not necessary. The global default is set to false, so when you run the vi, it is false. The button mechanical action is set to latch when released, so after clicking it will turn true until the main vi reads it, then it will automatically turn false. So you don't need the lower loops to keep writing false to it. If you just eliminate both lower loops, it will work fine. The only purpose I could see for the quitter vi is to have one button cause several vi's to stop. Instead of doing it this way, put one stop button in your main vi, create a reference (right click - create - reference), and wire this reference into all subvi's that the main calls. The subvi's must be changed to accept the reference and use it. This would be a much better method to close all vi's with one button.
You could also get rid of the sequence structure (it hides code and makes it more difficult to read). Just put all your code side by side. The error in/out wire will ensure that the execution order will be fixed, just like in your first sequence with the open file and write file functions. Just wire the error out of the write vi to the second write vi, and then the error out of the second write vi to the close vi. No sequence structure needed, and all your code is viewable on one screen.
- tbob
Inventor of the WORM Global

Problem using local variable in event loop

I have a state machine from which I want to monitor various controls, including "Start" and "Stop" buttons. Not every state needs to monitor the controls. At present, most states run timed loops. In the first state that reads the front panel, I have an Event structure (inside a While loop) that monitors the various controls' Change Value events. For numeric controls, I update variables (in shift registers) as needed. The "Start" button is used to end the While loop controlling the Event structure, allowing the State to exit to the next state.
My problem comes in subsequent states that employ this same idea. Here, I put a Local Variable bound to the Start button and use the same code, but it frequently happens that when I enter this particular state, I cannot "turn on" the control -- I push the button, but it stays off. Curiously, if it was On when I enter, I can turn it off, but then I'm stuck not being able to turn it on.
I mocked up a very simply routine that illustrates this. There are two sequences (corresponding to the two states). Both use an Event loop with a local variable bound to my Stop button (really this is an LED control with custom colors). I've deliberately moved the "initialization" (the declaration of the control in the block diagram) out of the Event loops -- putting it inside the first loop modifies the behavior in another strange way.
Here's my thinking on how I would expect this to work: The code outside Event Loop 1 should have little effect. Assume the Stop button is initially Off. You will "sit" in Event Loop 1 until you push the Stop button, changing its value to True; this value will be passed out of the Event case and cause the first While loop to exit. You now enter the second sequence. As I understand the Exit tunnel, it defaults to "False", so I'd expect to stay in the second Event loop until I turn the Stop button from On to Off, which will pass out a False, and keep me in the While for one more button push. However, this doesn't happen -- I immediately exit, as though the "True" value of the Stop local variable is being seen and recognized by the Event loop (even though it hasn't changed, at least not in the context of this second loop).
An even more curious thing occurs if I start this routine with the Stop button turned on. Now I start in my Event loop waiting for a change, but this time the change will be from On to Off, which won't cause an exit from the frame. This will be reflected by having the While loop count increment. We should now be in the state of the example above, i.e. in an Event loop waiting for the control to be pushed again, and turned On. However, clicking the control has no effect -- I cannot get it to "turn on".
Where am I going astray in my thinking? What is it about this method of doing things that violates the Labview paradigm? As far as I can tell, what I'm doing is "legal", and I don't see the flaw in my reasoning, above (of course not -- otherwise I'd have fixed it myself!). Note that because I'm using local variables inside Event loops (and I'm doing this because there are two places in my code where I want to do such testing), the Stop control is not latching (as required). Is there something that gets triggered/set when one reads a latched control? Do I need to do this "manually" using my local variable?
I'll try to attach the simple VI that illustrates this behavior.
Bob Schor
Attachments:
Simple Stop Conundrum.vi ‏14 KB

altenbach wrote:
Ravens Fan wrote:
NEVER have multiple event structures that share the same events.
Actually, that's OK. NOT OK is having multiple event structures in the same sequence structure.
See also: http://forums.ni.com/ni/board/message?board.id=170&message.id=278981#M278981
That's interesting. I had always thought I read more messages discouraging such a thing rather than saying it was okay. Your link lead me to another thread with this message. http://forums.ni.com/ni/board/message?board.id=170&message.id=245793#M245793. Now that thread was mainly concentrating on registered user events which would be a different, but related animal.
So if you have 2 event structures they each have their own event queue? So if you have a common event, one structure pulls it off its event queue and it does not affect the other structure's event queue? I guess the inherent problem with this particular VI was that the second event structure locked the front panel. Since the code never got to that 2nd event structure because the first loop never stopped because the change was from true to false. After reading your post and the others, I did some experimentation and turned off the Lock front panel on the 2nd structure, and that prevented the lockup of the program.
Overall, the example VI still shows problems with the architecture and I think your answer should put the original poster on the right track. I think as a rule I would probably never put the same event in multiple structures, I feel there are better ways to communicate the same event between different parts of a program, but I learned something by reading your reply and about how the event structures work in the background. Thanks.

How to: Transform Activity: Read global/local variable, execute java code

Could anyone please show me how to do that???

could you please elaborate your usecase? yes you can read global variable using getVariableData( ) xpath function and pass them as an argument to the processXSLT ( ) xpath function.
You can read the global or local variables inside java exec using, please refer samples/references/javaexec sample.

Reference to a local variable object returned by a method is alive?

I have an instance method getEmployee().
This method forms a local variable, Employee and returns it.
public Employee getEmployee()
Employee e = new Employee();
e.setSNo(sNo+=);
e.setMailBox();
return e;
There's another instance method in the same class that calls getEmployee() in this manner:-
Employee newEmployee = getEmployee();
newEmployee.printDetails();
I want to know whether the employee returned by getEmployee() is still alive when we are doing newEmployee.printDetails().
I am confused because in C, the lifetime of a local variable is limited only to the life time of the function. Once the function finishes, the local variable is considered garbage.
How does it work in case of Java?

No, It rarely has any use but can be used to unload things (from a cache for example). However I have never needed to do this. All I know is that finallizers can only be relied on to clear up memory. How or why you would do this is another question.
The GC runs when memory is low (not any other resource). It calls finalizers when it clears up objects. Therefore the only thing you can reliably release in a finalizer is memory. Other resources can become depleted without heap being depleated so you can't use finalizers to relialy clean up non-memory resources.
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some more info on escape analysis
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http://delivery.acm.org/10.1145/330000/320386/p1-choi.pdf?key1=320386&key2=0718563811&coll=Portal&dl=ACM&CFID=15151515&CFTOKEN=6184618
bit more recent and about runtime optimization (finalizers not handled)
http://ssw.jku.at/Research/Papers/Ko05/Ko05.pdf
I don't think that not handling finalizers is too much of a problem. Most objects that will benifit from stackability are small objects anyway (especially the built in wrapper types). Most objects that have custom finalizers tend to be pretty complicated.
matfud

Control buttons in local variables

hi,
i have been trying to do this for a long time. i just never learned how to make it work. can someone please guide me?
i have this program with many many local variables and i know that this forum absolutely hate LOCAL VARIABLES.
I want to program this the right way, so can you guys please help take a look at my code and see what i can do in order to REMOVE local variables if possible?
Best regards,
Krispiekream
Attachments:
test.vi ‏768 KB

does this work?
i split up the zip file to 2.88mb each.
i think there is a file size limit of 5mb
can you rename test01.zip to test.z01
can you rename test02.zip to test.z02
Best regards,
Krispiekream
Attachments:
test.zip ‏1078 KB
test01.zip ‏2847 KB
test02.zip ‏2847 KB

Create Type NI_MultipleNumericLimitTest for local variable

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jigg
CTA, CLA
teststandhelp.com
~Will work for kudos and/or BBQ~

While local variable initialized inside try block compiler throws error???

Check out this code where two local variables(one String and the other int type) is declared at the beginning of the method and initialized inside try block. now when i compile this app, it gives an error sayin' that Variables not been initialized. Can anyone tell me why compiler is throwin' an error message?
Many thanks.
import java.io.*;
public class Test{
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String aa;
int c;
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
System.out.println("EnterAnything:");
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jfbriere,
Thanks to u all.
that every reference to the variable is necessarily preceded
by execution of an assignment
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Can u clarify this?
--DM

Local variable hides a field

hi everyone ,
i am creating a button but it will show that local variable hides a field . this not an error or warning
JRadioButton a1Btn = new JRadioButton("Physical connectivity");
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declare
v_SETRESULT NUMBER;-----------this is declaration of local variable
begin
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INTO v_SETRESULT
FROM Visit--------this is my name of table;
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DATA A TYPE I VALUE 100.
PERFORM PRINT_DATA.
FORM PRINT_DATA.
           DATA A(10) TYPE C 'HELLO'.
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Best Regards,
Chaitanya

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Hi,
I'm having a problem with what is probably a 'feature' of labview
(using ver 6.1).
When running multiple SubVI's of the same type, any local variables
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Ed

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jvh

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Regards
Ray Farmer
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