Hi All,
In IOT analytics, we have a requirement of writing siddhi extension to get
the value for a particular json property when the json string and property
name are passed as parameters. The extension can be used as below,
*json:getProperty("jsonString","property_name")*
Since the above function is capable of returning any type
(Bool/long/string/..) as return values. Initially we tried it without
defining the return types. In that case, siddhi engine threw and exception
saying that return type of above is null and stream definitions does not
match. After that we tried to set the return type in execute method based
on the value. but seems like it is required to use the init method in
siddhi extension to set the return type. Finally what we did is to use the
third parameter which would indicate the type required for the return type
as follow,
if we need a double
*json.getProperty("jsonString", "latitude", 0.0d);*
if we need a long,
*json.getProperty(("jsonString", "timestamp", 0l);*
Is there any better way of achieving this ? or do we have a cast function
for string, so that we can later cast the value to a desired type?
Thanks.
Regards,
Megala
--
Megala Uthayakumar
Software Engineer
Mobile : 0779967122
_______________________________________________
Dev mailing list
Dev@wso2.org
http://wso2.org/cgi-bin/mailman/listinfo/dev
