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rd-lib-script former DatabeneScript by Volker Bergmann is a script language designed for simplifying test data generation. Text-targeted template languages like FreeMarker and general languages like JavaScript have specific problems, which can be avoided by a language tailored to the task of data generation.

rapiddwellerScript uses many elements familiar from C-style languages like Java and C#, but adds some specials:

  • More convenient object construction

  • intuitive date arithmetic

  • seamless integration and interaction with Benerator


Variable definition

<execute>x = 3</execute>

Variable assignment

<execute>x = x + 1</execute>

Object construction


new MyGenerator('alpha.txt', 23)


new MyGenerator { filename='alpha.txt', limit=23 }

Date arithmetic

new Date() + 5000

Java integration

(com.rapiddweller.common.SystemInfo.isWindows() ? 'win' : 'other')

Benerator integration

(context.contains('key') ? 'def' : 'none')



Line comments start with // and include the rest of the line.

Normal comments begin with /* and end with */

White Space

Spaces, tabs, CR, LF, \u000C

Data Types

Signed integral numbers: long, int, short, byte, big_integer

Signed floating point numbers: double, float, big_decimal

Alpha: string, char

Date/time: date, timestamp

Other: boolean, object (Java object), binary (byte[])


The first character must be an ASCII letter or underscore. An arbitrary number of subsequent characters may be ASCII letters, underscores or numbers.

Legal identifiers: _test, A1234, _999

Illegal identifiers: 1ABC, XÖ, F$D, alpha.beta

Escape Sequences

\b          Backspace

\t          Tab

\n          New Line

\r          Carriage Return

\f          Form Feed

\"          Double quote

\'          Single quote

\nnn    Octal encoded character

String Literal

Quoted with single quotes, e.g. Text

Decimal Literal

Supporting decimal syntax.

Legal decimal values: 1234.2345E+12, 1234.2345E12, 1234.2345e-12

Integral Number Literal

Supporting decimal, hexadecimal and octal syntax.

Legal decimal values: 0, 123

Legal octal values: 01, 00123

Legal hexadecimal values: 0x0dFa

Boolean Literal

Legal values: true, false

null Literal

Legal value: null

Qualified name


Legal values: com.rapiddweller.benerator.Generator, Generator

Constructor invocation

Works like in Java, e.g.

new MyGenerator('alpha.txt', 23)

Bean construction

Instantiates an object by the class' default constructor and calling property setters, e.g.

new MyGenerator { filename='alpha.txt', limit=23 }

is executed like

MyGenerator generator = new MyGenerator();



Method invocation

Can occur on static Java methods on a class or instance methods on an object.

Static method invocation:

instance method invocation: generator.generate()

Attribute access

Can occur on static Java attributes on a class or instance methods on an object.

Static attribute access:

instance attribute access:


Benerator can casts data types. Cast arguments are Benerator's simple types.

Examples: (date) '2009-11-23', (long) 2.34

Unary Operators

Arithmetic Negation: -

Bitwise complement: ~

Boolean Negation: !

Arithmetic Operators

Multiplication: *

Division: /

Modulo division: %

Addition: +, e.g. new Date() + 5000

Subtraction: -

Shift Operators

Left shift: << (in XML descriptor files use &lt;&lt;)

Right shift: >> (in XML descriptor files use &gt;&gt;)

Right shift: >> (in XML descriptor files use &gt;&gt;&gt;)

Relation Operators

<=, <, >, => (in XML descriptor files use &lt;=, &lt;, &gt;, =&gt;)

Equality Operators

==, !=

Bitwise Operators

And: & (in XML descriptor files use &amp;)

Exclusive Or: ^

Inclusive Or: |

Boolean Operators

And: && (in XML descriptor files use &amp;&amp;)

Or: ||

rapiddwellerScript uses shortcut evaluation like C, C++ and Java: First it evaluates the left hand side of an operation. If the result is completely determined by the result, it does not evaluate the right hand side.

Conditional Expression

... ? ... : …, e.g. a>3 ? 0 : 1


qualifiedName = expression