Field definition format

Each record field that a DataSource application can process is uniquely identified by a numeric id, but it's also normally given a name. The field names and ids are defined in add-field configuration items.

In a Caplin Platform blade, the field definitions are kept in a configuration file called fields.conf located in the blade_config directory of the blade.

add-field

Field definitions look like this:

add-field Desc       10001
add-field Amt        10002 
add-field Bid        10003
add-field Ask        10004
add-field PriceTime  10005

Looking at the first line of this example:

  • add-field is the configuration item that defines a field.
  • Desc is the name of the field (this is how the field is identified in client applications to which data is sent from Liberator via StreamLink).
  • 10001 is the field number (id) that is used to identify the field within DataSource messages passed between DataSource applications.

Syntax:

add-field FieldName FieldNumber

where the parameters are:

Name Type default Description
FieldName string [none] The name of the field.
Within a particular Caplin Platform installation, each field name must be unique.
You can configure multiple FieldNumbers to have the same FieldName if necessary, but not vice versa.
FieldNumber integer [none]

The number (id) of the field, between -65535 and 65535 inclusive.

Each field number is unique within a Caplin Platform installation.
By convention, you should use positive field numbers; negative ones are reserved for use by Caplin Systems Ltd.


See also: