cflock

<cflock 
timeout = "time-out in seconds" 
name = "lock name" 
scope = "Application|Server|Session|Request" 
throwOnTimeout = "yes|no" 
type = "readOnly|exclusive"> 
<!--- CFML to be synchronized. ---> 
</cflock>

<cflock timeout = "60" scope = "SESSION" type = "readOnly"> 
............... 
<cflock timeout = "60" scope = "SESSION" type = "Exclusive"> 
......... 
</cflock> 
</cflock>

<!--- 
This example shows how cflock can guarantee consistency of data updates to variables in the 
Application, Server, and Session scopes. ---> 

<!--- Copy the following code into an Application.cfm file in the 
application root directory. ---> 
<!---------------- Beginning of Application.cfm code ---------------> 
<!--- cfapplication defines scoping for a ColdFusion application and enables or disables 
storing of application and session variables. Put this tag in a special file called 
Application.cfm. It is run before any other ColdFusion page in its directory. ---> 

<!--- Enable session management for this application. ---> 
<cfapplication name = "ETurtle" 
sessionTimeout = #CreateTimeSpan(0,0, 0, 60)# 
sessionManagement = "yes"> 

<!--- Initialize session and application variables used by E-Turtleneck. Use session scope 
for the session variables. ---> 
<cflock scope = "Session" 
timeout = "30" type = "Exclusive"> 
<cfif NOT IsDefined("session.size")> 
<cfset session.size = ""> 
</cfif> 
<cfif NOT IsDefined("session.color")> 
<cfset session.color = ""> 
</cfif> 
</cflock> 

<!--- Use an application lock for the application-wide variable that keeps track of the 
number of turtlenecks sold. For a more efficient, but more complex, way of handling 
Application scope locking, see the "Developing ColdFusion Applications"---> 
<cflock scope = "Application" timeout = "30" type = "Exclusive"> 
<cfif NOT IsDefined("application.number")> 
<cfset application.number = 0> 
</cfif> 
</cflock> 

<!----------------------- End of Application.cfm -----------------------> 

<h3>cflock Example</h3> 

<cfif IsDefined("form.submit")> 
<!--- The form has been submitted; process the request. ---> 
<cfoutput> 
Thanks for shopping E-Turtleneck. You chose size <b>#form.size#</b>, 
color <b>#form.color#</b>.<br><br> 
</cfoutput> 

<!--- Lock the code that assigns values to session variables. ----> 
<cflock scope = "Session" timeout = "30" type = "Exclusive"> 
<cfparam name = session.size Default = #form.size#> 
<cfparam name = session.color Default = #form.color#> 
</cflock> 

<!---- Lock the code that updates the Application scope number of turtlenecks sold. ---> 
<cflock scope = "Application" timeout = "30" type = "Exclusive"> 
<cfset application.number = application.number + 1> 
<cfoutput> 
E-Turtleneck has now sold #application.number# turtlenecks! 
</cfoutput> 
</cflock> 

<cfelse> 
<!--- Show the form only if it has not been submitted. ---> 
<cflock scope = "Application" timeout = "30" type = "Readonly"> 
<cfoutput> 
E-Turtleneck has sold #application.number# turtlenecks to date. 
</cfoutput> 
</cflock> 

<form method="post" action="cflocktest.cfm"> 
<p>Congratulations! You selected the most comfortable turtleneck in the world. 
Please select color and size.</p> 
<table cellspacing = "2" cellpadding = "2" border = "0"> 
<tr> 
<td>Select a color.</td> 
<td><select type = "Text" name = "color"> 
<option>red 
<option>white 
<option>blue 
<option>turquoise 
<option>black 
<option>forest green 
</select> 
</td> 
</tr> 
<tr> 
<td>Select a size.</td> 
<td><select type = "Text" name = "size" > 
<option>XXsmall 
<option>Xsmall 
<option>small 
<option>medium 
<option>large 
<option>Xlarge 
</select> 
</td> 
</tr> 
<tr> 
<td>Press Submit when you are finished making your selection.</td> 
<td><input type = "Submit" name = "submit" value = "Submit"> </td> 
</tr> 
</table> 
</form> 
</cfif>