fluent-dsl

Simple proove of concept of http://blog.jooq.org/2012/01/05/the-java-fluent-api-designer-crash-course/.

very simple Sql dsl

Here is the grammar for this very simplistic sql dsl.

options {
    package='org.tw.fluentdsl.examples.sql';
}

#builder: build returns String;

select: column+ table+ (where | #builder) (orderby | #builder) #builder;

The maven plugin creates a set of interfaces to provide the architecture for this dsl.

Introduction to the fdsl - file

The fluent interfaces are defined within a fdsl file.

The syntax is very easy to grasp. First there is an option block were someone can tell the generator in which package the created interfaces should live:

options {
    package='org.tw.fluentdsl.examples.sql';
}

After that the interface rules follow. You define a start interface name and provide the following method rules. fluentdsl supports here the expressions:

• ( expr )
• expr | expr: simple or of expressions
• expr+: one or more of this expression
• expr optname expr: list of expressions with a provided subinterface name for the return value of the first expression.
• method: finally a method
• #interface: or an interface to expand here (look at the example #builder)

The interface rule itself is provided by this syntax:

interfacename: method expression;

All interfaces are generated except those that start with a # (look at the example #builder interface).

Methods can be provided only with a name or a fully defined one with parameters and return value. Again look at the example: build method is defined with a String return value:

testiface: mymethod(String value1, String value2) returns int;

Maven Plugin usage

The fdsl - files are provided within the src/fluentdsl directory and the interfaces are generated within generated-sources. The plugin itself is configured with something like this:

<plugin>
    <groupId>org.tw</groupId>
    <artifactId>fluentdsl-maven-plugin</artifactId>
    <version>1.0-SNAPSHOT</version>
    <executions>
        <execution>
            <id>default-descriptor</id>
            <goals>
                <goal>generate</goal>
            </goals>
        </execution>
    </executions>
</plugin>