Jbase: embedding Java expressions in Xtext DSLs

In this paper we present Jbase, an expression language that can be used to introduce Java expressions and statements in Xtext DSLs. Jbase extends and customizes Xbase, the Java-like expression framework shipped with Xtext. Although Xbase already provides a complete integration with the Java type system and with all the existing Java libraries, its expression language is only Java-like, and this limits its adoption in contexts where Java-like is not enough. Jbase, built on top of Xtext/Xbase, offers all the powerful features of these frameworks and provides Java syntax, and the adaption of the Xbase type system and code generator accordingly. It also keeps the simplicity of Xbase, so that, by using Jbase, it is straightforward to introduce Java expressions and statements into an Xtext DSL. We believe that Jbase is a valuable tool for embedding Java expressions in a DSL, and also for extending Java expression syntax in extensions to Java.