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Application Object
Application.Lock Method
   Syntax:
   Parameters:
   Return Values:
   Remarks:
  Examples:
Application.Unlock Method
   Syntax:
   Parameters:
   Parameters:
   Remarks:
  Examples:

Application Object

One of the key functions of Application Object is the application control on the server.

Application.Lock Method

Application.Lock method locks the properties of Application object by only one client at a time for preventing other clients from modification..

Syntax:

Lock(
)

 Or in an ASP file. Imply

<% Application.Lock %>

Parameters:

void

This method has no parameters

Return Values:

void

This method has no parameters

Remarks:

After calling the Application.Lock method, if the Application.Unlock method is not called explicitly, the server unlocks the locked Application object when the ASP file processing ends or times out. Therefore a lock on the Application object only persists for a very short time.

However, if one page locks the application object and a second page tries to locks the same application object while the first page still has it locked, the second page will wait for the first to finish, or until the Server.ScriptTimeout limit is reached.

If the Server.ScriptTimeout limit is reached, the following ASP error is returned which cannot be captured:

HTTP 500.100 - Internal Server Error - ASP error
Internet Information Services

Active Server Pages, ASP 0113 (0x80004005)
The maximum amount of time for a script to execute was exceeded.
You can change this limit by specifying a new value for the property
Server.ScriptTimeout or by changing the value in the IIS administration tools

To reduce the possibility of having an ASP page time out, write a COM+ object that uses the COM+ ObjectContext object to update the Application collection, and then call the COM+ object from an ASP. COM+ objects execute slightly faster than ASP pages.

The application collection can be modified without locking the application object to edit. Therefore two pages can modify the same application without causing any error, however, the modification will become inconsistent.

Examples:

  • Use Application.Lock to prevent more than on client accessing and altering the application variable simultaneously

    ASP script command:

    <%
    Application.Lock
    Application("CountNo") = Application("CountNo") + 1
    Application.Unlock
    %>

Application.Unlock Method

Application.UnlLock method unlocks or releases the properties of Application object by the only one client at a time for allowing other clients to modify.

Syntax:

Unlock(
)

 Or in an ASP file. Imply

<% Application.Unlock %>

Parameters:

void

This method has no parameters

Parameters:

void

This method has no parameters

Remarks:

The Application.Lock method is cumulative, therefore for the same script, the number of Lock method calls should be equal to the number of Unlock method calls in order to fully release the application, otherwise the application remains Locked.

After calling the Application.Lock method , if the Application.Unlock method is not called explicitly, the server unlocks the locked Application object when the ASP file processing ends or times out. Therefore a lock on the Application object only persists for a very short time.

However, if one page locks the application object and a second page tries to locks the same application object while the first page still has it locked, the second page will wait for the first to finish, or until the Server.ScriptTimeout limit is reached.

If the Server.ScriptTimeout limit is reached, the following ASP error is returned which cannot be captured:

HTTP 500.100 - Internal Server Error - ASP error
Internet Information Services

Active Server Pages, ASP 0113 (0x80004005)
The maximum amount of time for a script to execute was exceeded.
You can change this limit by specifying a new value for the property
Server.ScriptTimeout or by changing the value in the IIS administration tools

To reduce the possibility of having an ASP page time out, write a COM+ object that uses the COM+ ObjectContext object to update the Application collection, and then call the COM+ object from an ASP. COM+ objects execute slightly faster than ASP pages.

 The application collection can be modified without locking the application object to edit. Therefore two pages can modify the same application without causing any error, however, the modification will become inconsistent.

Examples:

  • Use same number of Application.Unlock to release the application for other clients accessing and altering the application variable simultaneously

    ASP script command:

    <% 
    Application.Lock
    Application.Lock
    Application("CountNo") = Application("CountNo") + 1
    Application.Unlock
    Application.Unlock
    %>


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ID: 120200035 Last Updated: 10/2/2012 Revision: 0 Ref:

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References

  1. Active Server Pages,  
  2. ASP Overview,  
  3. ASP Best Practices,  
  4. ASP Built-in Objects,  
  5. Response Object,  
  6. Request Object,  
  7. Server Object (IIS),  
  8. Application Object (IIS),  
  9. Session Object (IIS),  
  10. ASPError Object,  
  11. ObjectContext Object (IIS),  
  12. Debugging Global.asa Files,  
  13. How to: Debug Global.asa files,  
  14. Calling COM Components from ASP Pages,  
  15. IIS ASP Scripting Reference,  
  16. ASP Keywords,  
  17. Creating Simple ASP Pages,  
  18. Including Files in ASP Applications,  
  19. ASP Overview,  
  20. FileSystemObject Object,  
  21. http://msdn.microsoft.com/en-us/library/windows/desktop/ms675944(v=vs.85).aspx,  
  22. ADO Fundamentals,  
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