ColdFusion 8 introduces this to deal with calls to methods that don't exist. This can be used for a few things but the most interesting of which it dynamic set and get methods to access an objects' properties.
Here for my reference more than anything and shown in a CFC.
Test.cfc:
<cfcomponent> <cfset VARIABLES.property1 = ""> <cfset VARIABLES.property2 = ""> <cffunction name="onMissingMethod" output="false"> <cfargument name="missingMethodName" type="string" required="true"> <cfargument name="missingMethodArguments" type="struct" required="true"> <cfset var action = Left(ARGUMENTS.missingMethodName, 3)> <cfset var property = Right(ARGUMENTS.missingMethodName, Len(ARGUMENTS.missingMethodName) - 3)> <cfif action EQ "get" AND StructKeyExists(VARIABLES, property)> <cfreturn VARIABLES[property]> <cfelseif action EQ "set" AND StructKeyExists(VARIABLES, property)> <cfset VARIABLES[property] = ARGUMENTS.missingMethodArguments[1]> <cfelse> <cfthrow type="InvalidMethodNameException" message="The method #ARGUMENTS.missingMethodName# was not found in component<br />#GetCurrentTemplatePath()#"> </cfif> </cffunction> <cffunction name="setProperty2"> <cfargument name="property2"> <cfset VARIABLES.property2 = ARGUMENTS.property2> </cffunction> <cffunction name="getProperty2"> <cfreturn VARIABLES.property2> </cffunction> </cfcomponent>
onMissingMethod checks for 'set' or 'get' at the start of the method name and assumes the rest is a reference to a property in the CFC. If it can't set or get a property, it throws the same error it would have if onMissingMethod wasn't defined.
test.cfm:
<cfset test = CreateObject("component", "test")> <cfset test.setProperty1("This is set with the onMissingMethod... method")> <cfset test.setProperty2("This will be set with the setProperty2 method")> <cfoutput> <p>#test.getProperty1()#</p> <p>#test.getProperty2()#</p> </cfoutput> The above code shows how you can override the dynamic setters and getters by defining them yourself.