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Subject NamesEach TIBCO Adapter SDK message bears a subject name.Data-producing programs generate new data messages, label them with subject names, and send them using TIBCO Adapter SDK software. Data consumers receive data by listening to subject names. A consumer listening to a name receives all data labeled with a matching name, from the time it begins to listen until it stops listening.Subject Name SyntaxSubject-based addressing™ technology places few restrictions on the syntax and interpretation of subject names. System designers and developers have the freedom (and responsibility) to establish conventions for using subject names. The best subject names reflect the structure of data in the application itself.Each subject name is a string of characters that is divided into elements by the dot (.) character. It is invalid to incorporate the dot character into an element by using an escape sequence.TIBCO Adapter SDK limits subject names to a total length of 255 characters (including dot separators). The maximum element length is 252 characters (dot separators are not included in element length). Typical subject names are shorter and use fewer elements. To maximize speed and throughput rates, use short subject names.The following are examples of correct subject names:
• The following are examples of incorrect subject names:
• News..Natural_Disasters.Flood (null element)
• WRONG. (null element)
• .TRIPLE.WRONG.. (three null elements)Table 35 lists special characters in subject names.
Table 35 Special Characters in Subject Names It is illegal for application programs to send to subjects with underscore as the first character of the first element, except _INBOX and _LOCAL.
Programs can listen for wildcard subject names to access a collection of related data through a single subscription.
• The asterisk (*) is a wildcard character that matches any one element. The asterisk substitutes for whole elements only, not for partial substrings of characters within an element.
• Greater-than (>) is a wildcard character that matches all the elements remaining to the right.A listener for a wildcard subject name receives any message whose subject name matches the wildcard.The examples in Table 36 illustrate wildcard syntax and matching semantics.
Listening to this wildcard name Matches messages with names like these: But does not match messages with names like these (reason): RUN.Run.run (extra element)Run.away (case)RUN (missing element) Giants.vs.Yankees (position)Yankees.beat.Sox (vs≠beat)Yankees.vs (missing element) your (missing elements)Pick.up.your.foot (position) HOME.RUN (position)Run.away (case)RUN (missing element)Table 37 shows subject names that use invalid wildcards.
Table 37 Invalid Wildcards in Subject Names Asterisk (*) must take the place of one whole element, not a substring within a element. Greater-than (>) can only appear as the right-most character. TIBCO Adapter SDK software interprets this as a specific subject name.
Although transports do not prevent you from sending to wildcard subjects, doing so can trigger unexpected behavior in other programs that share the network.Names that begin with an underscore character (_) are called distinguished subject names. Distinguished names indicate special meaning, special handling, or restricted use.
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Copyright © TIBCO Software Inc. All Rights Reserved |