Native Operators for the Efficient Query of Jolie Tree-like Values

Distributed systems are ubiquitous in modern computing, from household devices to global cloud platforms. Programming these systems introduces challenges beyond local programming: services must communicate across network boundaries, handle heterogeneous protocols, and process structured data exchanged in formats like JSON and XML. Jolie is a programming language designed specifically for service-oriented distributed systems. Its distinctive feature is protocol independence: business logic remains unchanged whether services communicate via HTTP, SOAP, or binary protocols. This separation between behavior and deployment simplifies integration across heterogeneous systems. Jolie realizes protocol independence through tree-structured variables whose structure is compatible with the data exchanged between services. Every variable in Jolie is a tree that can hold a root value and arbitrarily nested children. This design eliminates the impedance mismatch between the hierarchical data formats services exchange (JSON, XML) and the language’s native data model—no serialization libraries or schema bindings required. However, while Jolie’s tree variables elegantly represent structured data, the language provides no native primitives for querying these structures. Since the language doesn’t give native support to structuring queries on data, developers must write nested loops to traverse and filter tree data. This thesis presents PATHS and VALUES, native Jolie language primitives for declarative tree querying. By directly exploiting Jolie’s internal tree representation, these primitives eliminate both the verbosity of imperative traversal and the performance penalties of external libraries. A query that previously required nested loops or incurred substantial memory duplication becomes a single lightweight declarative expression.