Aerospike Expression DSL

Note

This is a developer preview, not yet ready for production use, but with future releases planned. We appreciate feedback from the Aerospike developer community through GitHub issues or the Aerospike Developers Discord.

Aerospike Expression DSL is a Java library that allows translating a canonical Aerospike Expression DSL string into an Aerospike Expression.

Aerospike Expressions is a functional language for applying predicates to bin data and record metadata.
Expressions are essential to different areas of server functionality:

• Secondary indexes
• Filter Expressions (introduced in Aerospike Database 5.2)
• XDR Filter Expressions (introduced in Aerospike Database 5.3)
• Operation Expressions (introduced in Aerospike Database 5.6)

Why DSL

A filter expression is created by combining the expression predicate classes using Polish notation, compiling it, and then attaching it to the operation. This approach has several limitations, including a difficult developer experience.

Expressions require the use of native language clients. As a result, filter expressions cannot be used in places that only accept a filter written in text. As a workaround, expressions can be created separately using a native client and exported as a base64-encoded string.

A text-based DSL can be converted into Expressions and be used across frameworks, connectors, gateways, data browsers, IDE plug-ins, and all language-native clients. Having a standard way to describe filters is easy to document and makes it accessible to developers regardless of their language preferences.

Prerequisites

• Java 17 or later
• Aerospike Server version 5.2+

Build from source

Aerospike Expression DSL uses ANTLR v4 for its parsing capabilities.
When modifying the grammar file you will need to re-generate the ANTLR sources by running the following command:

mvn clean generate-sources compile

Usage examples

Filter expression

String input = "$.intBin1 > 100";
Expression expression = ConditionTranslator.translate(input);

Will return the following expression:

Exp.build(
    Exp.gt(
        Exp.intBin("intBin1"),
        Exp.val(100))
);

License

Licensed under the Apache 2.0 License.