Select iTunes DJ Playlist. For older versions (pre iTunes 11). Useful Applescript UI scripting debugging

select_itunes_dj.applescript

on select_dj_playlist(playlist_name)
	try
		with timeout of 10 seconds
			tell application "Finder"
				set os_version to version
			end tell
			
			set errorString to ""
			
			tell application "System Events"
				tell application process "iTunes"
					set visible to true
					
					if version of application "iTunes" contains "10.0" or version of application "iTunes" contains "10.1" or version of application "iTunes" contains "10.2" or version of application "iTunes" contains "10.3" or version of application "iTunes" contains "10.4" or version of application "iTunes" contains "10.5" or version of application "iTunes" contains "10.6" or version of application "iTunes" contains "10.7" then
						set playlist_popup to pop up button 1 of window "iTunes"
					else if version of application "iTunes" contains "9.1" or version of application "iTunes" contains "9.0" or version of application "iTunes" contains "9.2" then
						set playlist_popup to pop up button 1 of splitter group 1 of window "iTunes"
					else
						set playlist_popup to UI element 3 of UI element 3 of splitter group 1 of window "iTunes"
					end if
					
					set switchingSuccess to false
					
					repeat 3 times
						try
							-- the way carbon menus (at least the iTunes carbon menu) are structured has changed in 10.6
							if os_version contains "10.5" then
								click playlist_popup
								pick menu item playlist_name of UI element 2
							end if
							
							if os_version contains "10.7" or os_version contains "10.8" then
								set frontmost to true
								tell window "iTunes"
									set focused of pop up button 1 to true
									set value of pop up button 1 to playlist_name
									
									-- this 'clicks' the button; bad hack for iTunes DJ
									delay 0.5
									keystroke " "
									delay 0.5
									keystroke " "
									delay 0.5
									
									click button "Refresh"
								end tell
							else
								--return name of every menu item
								--tell application "System Events"
								--	key code 125 using option down
								--end tell
								--return every UI element
								--return menu 1 of window "iTunes"
								--click menu item playlist_name of menu of window "iTunes"
								--click menu item playlist_name
							end if
							
							set switchingSuccess to true
							exit repeat
						on error errorMessage number errorNumber
							set errorString to errorString & " " & errorMessage & "(" & errorNumber & ")"
							delay 1
						end try
					end repeat
					
					--some useful debugging things
					--return name of every UI element
					--perform action "AXPress" of playlist_popup					
					--return value of attribute "AXChildren" of UI element 2
					
					set visible to false
				end tell
			end tell
			
			refresh_dj_playlist()
			
			if length of errorString > 1 then
				if switchingSuccess then
					do shell script "/usr/bin/logger " & quoted form of errorString
				else
					return "Error: " & errorString
				end if
			end if
		end timeout
	on error errorMessage number errorNumber
		return "Error: setting dj playlist: " & errorMessage & " " & errorNumber
	end try
end select_dj_playlist

on normalize_itunes_browser()
	try
		with timeout of 10 seconds
			tell application "iTunes"
				if (view of front browser window) is playlist "iTunes DJ" then
					set view of front browser window to playlist "Music"
				end if
				
				set view of front browser window to playlist "iTunes DJ"
			end tell
		end timeout
	on error
		return "Error: refreshing dj playlist"
	end try
end normalize_itunes_browser

on dump_itunes_interface()
	tell application "System Events"
		tell process "iTunes"
			return entire contents
		end tell
	end tell
end dump_itunes_interface