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Associate Technical Lead, WSO2
Manipulating XML, JSON and SQL Data Types with Ballerina
Shafreen Anfar
Let’s Begin With a Story!Time. Effort. Money.
A Developer’s Story
James (CEO of DataDump Inc.)
William (Conservative, butworking hard)
Henry(Open-minded andworking smart)
James wants his developers to develop a REST service that exposes employee data of his company as a service.
James: Oh! I also want the resource representation to be XML.
A Developer’s Story
• Willam’s approach– Chose Java– Decide on a JAX-RS implementation – Decide on a suitable XML library– Extract data from the database
A Developer’s Story
• Willam’s approach– Using XML library, convert it into
XML– Set it as the response of the service – Deploy it on some web container
A Developer’s Story
Not anymore!Thanks to Ballerina, things are different now.
A Developer’s Story Sounds Complex?
Henry, chose Ballerina and Bob is his uncle!
A Developer’s Story
Henry’s code is not only simple, but also gets the Job done effectively.
A Developer’s Story
Simplicity is something we strive to achieve in Ballerina.
“Simplicity is the ultimateSophistication” - Leonardo da Vinci
A Developer’s Story
Datatable
• Ballerina natively supports handling tabular data structures
• Datatable can be casted to a struct, XML or JSON• Supports data streaming• Work in progress
– Letting users populate datatables and directly write to the DB.
Datatable in Ballerina
XML
• No Need to Worry About Third-Party Libraries!• XML is part of the type system of Ballerina• Provides compile time validation• Ballerina has its extended version of XML spec
– James Clark (https://en.wikipedia.org/wiki/James_Clark_(programmer))
XML in Ballerina
XML in Ballerina : Constructs
XML in Ballerina : Interpolation
XML in Ballerina : Functions
Back to the Story!
Now, James wants William and Henry to develop another service to see which employees are eligible for awards for the current quarter.
But this time James wants it to be mobile friendly.
A Developer’s Story
William goes back to the whiteboard and start designing!
A Developer’s Story
• Decide on a JSON implementation • Use the previously used XML library and
construct payload from the response stream• Do the logic to get the list of eligible
employees• Serialize the XML payload to JSON
A Developer’s Story
A Developer’s Story
Sounds Like a Lot of Work!
Once again, Henry chose Ballerina and Bob is his uncle!
A Developer’s Story
Business logic
JSON
• No need to worry about third-party libraries• JSON is part of the type system of Ballerina• Provides compile time validation• Can easily add, remove, modify• Constrained JSON provides extra validation• Similar to maps and structs in Ballerina
JSON in Ballerina
JSON in Ballerina : Constructs
JSON in Ballerina : Constructs
JSON in Ballerina : Navigating
A Developer’s Story
Who’s the Smarter and Happier DeveloperNow?
Henry, the Ballerina developer ... – Can focus on the exact requirement– Saves time and effort– Ultimately saves money– Writes simple and readable code
A Developer’s Story
A Developer’s Story
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