07-java

Java Code Generation

This example demonstrates how to generate Java code directly from an Orchestra specification.

This feature allows developers to streamline the creation of applications that process Orchestra-specified data using the Orchestra Java library with built-in support for multiple data encodings.

The plugin generates Java classes for the messages, components, fields, and codesets specified in the Orchestra specification.

The example uses the Order Book specification from a previous example.

Configuration

To generate Java code from an Orchestra specification, additional type information is needed to map each datatype in the Orchestra specification to the corresponding Java datatype.

Add the encoding extension to the build.gradle file and define a datatype mapping for each datatype in your Orchestra specification.

Java code generation is enabled by the presence of the Java codeGen extension. A packageName value must be provided.

orchestra {
  specification {
    markdown {}

    // Specify the corresponding Java type for each datatype in the Orchestra specification.
    encoding {
      datatypeMapping([
        Double: [
          Java: 'double',
        ],
        Integer: [
          Java: 'int',
        ],
        Price: [
          Java: 'double',
        ],
        Quantity: [
          Java: 'int',
        ],
        String: [
          Java: 'string',
        ],
        Timestamp: [
          Java: 'instant',
        ],
      ])
    }
  }

  // Enable Java code generation
  java {
    codeGen {
      packageName = 'org.example.orchestra'
    }
  }
}

Run

Use the Gradle wrapper to run the example.

$ ./gradlew :basic-examples:07-java:runExample

Note: runExample is wired to call the orchestraGenerateJava task from the Orchestra plugin.

Results

The Java source code will be output to the Gradle build folder.

$ ./basic-examples/07-java/build/generated/sources/orch-gen-java/main/java