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Find details on the SPL language, toolkits, APIs, commands, and more.
Streams Processing Language (SPL)
Streams Processing Language (SPL) is a distributed data flow composition language that is used in Teracloud® Streams. SPL has primitive types, program structures, and definitions that are tailored for streaming data.
Annotations
Operators can be annotated. Annotations influence the run time behavior of stream applications.
Autonomous annotation
The SPL annotation @autonomous defines autonomous regions and can be applied to an operator or operators in an application graph to remove those operators from a consistent region.

Welcome
Learn about the core capabilities of Teracloud® Streams, its architecture, and key concepts.
Installing
Use this information to install, upgrade, and uninstall the Teracloud® Streams product.
Configuring
Create a basic or an enterprise domain which is a single point for configuring and managing common resources, security, and instances.
Administering
Administer the product by using the Teracloud® Streams graphical user interface, APIs, or the streamtool command-line interface.
Developing
Develop stream applications with the Streams Processing Language (SPL), Java, and Python.
Troubleshooting
Resolve problems with Teracloud® Streams using the troubleshooting tools provided with the product as well as the resources offered by Teracloud Support.
Reference
Find details on the SPL language, toolkits, APIs, commands, and more.
- APIs
  Application programming interfaces (APIs) provide functions that simplify applications development.
- Job configuration overlays
  You can specify or change configuration parameters when you use the submitjob or updateoperators operations. The settings control submission constraints, host constraints and locations, and operator status. Parameters are captured and updated in the configuration JSON file. When you change the values in the job configuration overlay file, the changes override any previously set values.
- Commands
  Teracloud® Streams provides a number of commands you use to perform tasks.
- Operator model
  An operator model is an XML document that describes the basic properties of a primitive operator.
- Streams Processing Language (SPL)
  Streams Processing Language (SPL) is a distributed data flow composition language that is used in Teracloud® Streams. SPL has primitive types, program structures, and definitions that are tailored for streaming data.
  - Language overview
    SPL contains types, expressions, statements, functions, clauses, and other elements of a programming language.
  - Grammar notation
    This language specification adopts a flavor of Backus-Naur Form (BNF) to describe the syntax of language features.
  - Lexical syntax
    SPL defines a set of rules to determine the syntax of a program.
  - Grammar overview
    Here is the SPL grammar syntax, with references to the sections that contain the semantics.
  - Expression language
    Though SPL is a streaming language, there are many places where it uses expressions that are found in traditional imperative or functional languages.
  - Annotations
    Operators can be annotated. Annotations influence the run time behavior of stream applications.
    - Autonomous annotation
      The SPL annotation @autonomous defines autonomous regions and can be applied to an operator or operators in an application graph to remove those operators from a consistent region.
    - Catch annotation
      The SPL annotation @catch indicates that exceptions of a specified type that are thrown by an operator while processing tuples are caught.
    - Consistent annotation
      The SPL annotation @consistent that defines consistent regions can be configured according to how and when the regions are drained, and the maximum amount of time that a region is allotted for a drain or reset process to complete.
    - Endpoint annotation
      The SPL annotation @endpoint provides documentation to augment generated API documentation for a particular endpoint of the data exchange API that is associated with a Teracloud® Streams job.
    - EventTime annotation
      The SPL annotation @eventTime specifies that all the output ports of operators where the annotation is in effect emit a stream with event-time values and watermarks. An event-time graph starts from the output port of an event-time source operator. The event-time source operator inserts watermarks into the output stream from time to time.
    - Parallel annotation
      To take advantage of data-parallelism, apply the @parallel annotation to invocations of primitive or composite operators. Data-parallelism means replicating copies of operators and splitting streams so that different tuples go to each set of replicas.
    - Service annotation
      The SPL annotation @service provides documentation to augment generated API documentation for the data exchange API that is associated with a Teracloud® Streams job.
    - Threading annotation
      The SPL @threading annotation determines the threading model to use for the operators inside of a composite operator.
    - View annotation
      The SPL annotation @view specifies that a view is to be created when the streams application is run.
  - Types
    SPL has several primitive types that are tailored for streaming, and a few composite types that are inspired by scripting languages but statically checked. The following topics describe the types, how to define them, and how to convert values between different types.
  - Operators
    Operators process tuples in an incoming stream and produce an output stream as a result. SPL supports two kinds of operators: primitive operators and composite operators. A primitive operator is written in C++ or Java™. A composite operator is written in SPL and contains a reusable stream subgraph.
  - Program structure
  - Operator config clause
    The config clause specifies hints and directives that influence how the compiler builds an operator invocation, or how the runtime system runs it.
- Toolkits
  A toolkit is a set of SPL artifacts, which are organized into a package. Toolkits make SPL or native functions and primitive or composite operators reusable across different applications.
- SPLDOC markup
  You can use SPLDOC markup in the descriptions associated with the SPL artifacts in a toolkit. The spl-make-doc command generates HTML documentation from the marked up artifacts.
Glossary
Use this glossary to find terms and definitions for Teracloud® Streams.

Autonomous annotation

The SPL annotation @autonomous defines autonomous regions and can be applied to an operator or operators in an application graph to remove those operators from a consistent region.

The @autonomous annotation can be applied to primitive and composite operators. Thus causing the operator state to be independent from other operators in the graph and revert to its default behavior. Teracloud® Streams calculates the boundaries of the autonomous region that is based on the reachability graph of the annotated operator. The reachability graph of the annotated operator stops when one of the following conditions are met.

There is an operator with a @consistent annotation.
An operator in the reachability graph of the annotated operator has at least one input port with incoming stream connections that come exclusively from operators in a consistent region and at least one input port with incoming stream connections that come exclusively from autonomous operators. In this case, the common operator is considered to be in the consistent region.

If an operator is autonomous, the successful completion of a drain or a reset of a consistent region does not depend on it. In addition, failures of this operator do not cause the reset of a consistent region, unless they are in a PE in which there are other operators in a consistent region.

The SPL compiler reports errors when an @autonomous annotation is applied in the following situations.

When @autonomous is placed at the same operator invocation as a @consistent annotation.
When @autonomous is applied to operators that, via its own stream connections or its reachability graph, connect to the input port of an operator that has incoming stream connections from both autonomous operators and operators within a consistent region.