AllJoyn Symbols (@, !, ?, $)

asked 2014-08-07 14:28:55 -0700

AllJoyner gravatar image

Hi, I was wondering what each of these symbols mean (@, !, ?, $). I have read that we use $ to define secure interface, and I have used ? when I was calling BusMethods. Are ! and @ used for BusSignal/BusProperty? If so, what is the point of these symbols and is it mandatory to always use them? Also, are there any other symbols other than these and what are they used for?

Thank you!!

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answered 2014-08-07 15:03:01 -0700

bspencer gravatar image

These symbols are used in the AllJoyn Thin Core library and they are to aid in parsing the strings that you or others as a developer to set in a table that represents the AllJoyn Interface. A '@' indicates a Bus Property, a '!' indicates a Bus Signal and a '?' indicates a Bus Method. The '$' when used on the interface name marks it as secure, a '#' marks an interface as being explicitly unsecure. With the addition of Events and Actions in the 14.06 software the Thin Client now includes a descriptor symbol for a BusSignal to indicate it is a Sessionless signal. A '!' followed by a '&' ("!&") marks a signal as being explicitly a sessionless signal. In order to describe the input and output values of a BusMethod or Bus Signal the characters '>' and '<' are used as output and input descriptors.

These symbols are only used by the AllJoyn Thin Core Library. You can find the parsing of the interface strings in the aj_introspect.c file with the symbol definitions starting at line 86.

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Thanks Brian, just a side question regarding properties. Is it enough to have a property in AJTCL app interface only and then when that property is changed I would send signal to AJSCL app, or do I need to have BusProperty and BusSignal in both AJTCL and AJSCL interface. Thanks!

AllJoyner ( 2014-08-08 07:18:46 -0700 )edit

You would need to have your own signal for when a BusProperty changes at this time.

bspencer ( 2014-08-14 11:07:16 -0700 )edit
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Asked: 2014-08-07 14:28:55 -0700

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Last updated: Aug 07 '14