Basic Types

Provides introduction to basic Siddhi attribute types which are int, long, float, double, string, and object, and some key functions such as convert(), instanceOf...(), and cast().

In Siddhi, other types such as list, map, etc, should be passed as object into streams. For more information on other types refer other examples under Values and Types section.

For information values, and other useful functions, refer the Siddhi query guide.

define stream PatientRegistrationInputStream (
                 seqNo long, name string, age int,
                 height float, weight double, photo object,
                 isEmployee bool, wardNo object);

define stream PatientRegistrationStream (
                 seqNo long, name string, age int,
                 height double, weight double, photo object,
                 isPhotoString bool, isEmployee bool,
                 wardNo int);

@info(name = 'Type-processor')
from PatientRegistrationInputStream
select seqNo, name, age,
       convert(height, 'double') as height,
       weight, photo,
       instanceOfString(photo) as isPhotoString,
       isEmployee,
       cast(wardNo, 'int') as wardNo
insert into PatientRegistrationStream;

define stream PatientRegistrationInputStream (
                 seqNo long, name string, age int,
                 height float, weight double, photo object,
                 isEmployee bool, wardNo object);

Defines PatientRegistrationInputStream having information in all primitive types.

 
define stream PatientRegistrationStream (
                 seqNo long, name string, age int,
                 height double, weight double, photo object,
                 isPhotoString bool, isEmployee bool,
                 wardNo int);

Defines the resulting PatientRegistrationStream after processing.

 
@info(name = 'Type-processor')
from PatientRegistrationInputStream
select seqNo, name, age,
 
       convert(height, 'double') as height,

convert() used to convert float type to double.

 
       weight, photo,
 
       instanceOfString(photo) as isPhotoString,

instanceOfString() checks if the photo is an instance of string.

 
       isEmployee,
 
       cast(wardNo, 'int') as wardNo

cast() cast the value of wardNo to int.

 
insert into PatientRegistrationStream;

Input

Below event is sent to PatientRegistrationInputStream,

[1200098, 'Peter Johnson', 34, 194.3f, 69.6, #Fjoiu59%3hkjnknk$#nFT, true, 34]

Here, assume that the content of the photo (#Fjoiu59%3hkjnknk$#nFT) is binary.

Output

After processing, the event arriving at PatientRegistrationStream will be as follows:

[1200098, 'Peter Johnson', 34, 194.3, 69.6, #Fjoiu59%3hkjnknk$#nFT, false, true, 34]

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