Prerequisite

Install Node.js 16 or above. (Verify by node --version)

Install Java 11 or above. (Verify by java --version)

Install TypeSpec 0.54.

Initialize TypeSpec Project

Follow TypeSpec Getting Started to initialize your TypeSpec project.

Make sure npx tsp compile . runs correctly.

Add TypeSpec-Java

Make sure the version of TypeSpec-java release depends on same version of "@typespec/compiler" as in your TypeSpec project.

Modify package.json, add one line under dependencies:

    "dependencies": {
      "@typespec/compiler": "latest",
      "@typespec/rest": "latest",
      "@azure-tools/typespec-azure-core": "latest",
+      "@azure-tools/typespec-java": "latest"
    },

Run npm install again to install @azure-tools/typespec-java.

Modify (or create) tspconfig.yaml, specify emit as @azure-tools/typespec-java:

emit:
  - "@azure-tools/typespec-java"

Generate Java

npx tsp compile client.tsp --emit=@azure-tools/typespec-java or npx tsp compile client.tsp --emit=@azure-tools/typespec-java --options='@azure-tools/typespec-java.emitter-output-dir=<target-folder>.

If emitter-output-dir option is not provided, generated Java code will be under tsp-output/@azure-tools/typespec-java folder.

Optional Configuration

SDK

One can further configure the SDK generated, using the emitter options on @azure-tools/typespec-java.

emit:
  - "@azure-tools/typespec-java"
options:
  "@azure-tools/typespec-java":
    emitter-output-dir: "{project-root}/azure-ai-language-authoring"
    namespace: "com.azure.ai.language.authoring"
    service-name: "Authoring"
    service-versions:
      - "2022-05-15-preview"
    enable-sync-stack: true
    stream-style-serialization: true
    generate-samples: true
    generate-tests: true
    examples-directory: "./examples"
    partial-update: false
    models-subpackage: "models"
    custom-types-subpackage: "implementation.models"
    custom-types: InternalModel1,InternalModel2

Convenience API

By default, TypeSpec-Java generates all protocol APIs and convenience APIs. A few exceptions are API of JSON Merge Patch, and API of long-running operation with ambiguous response type.

See "convenientAPI" decorator from typespec-client-generator-core.

Customization

All post-code customizations listed in this documentation are supported for code generated from TypeSpec.

To configure customization with TypeSpec, Java's emitter options should include a customization-class. The customization-class option should specify the path to the file containing the customization code relative to emitter-output-dir. Note that the path should end with src/main/java/<YourCustomizationClassName>.java. The recommended practice is to place the customization class in <output-dir>/customization/src/main/java/<YourCustomizationClassName>.java and the customization-class option will have the value of customization-class: customization/src/main/java/<YourCustomizationClassName>.java. See example tspconfig.yaml below:

emit:
  - "@azure-tools/typespec-java"
options:
  "@azure-tools/typespec-java":
    emitter-output-dir: "{project-root}/azure-ai-language-authoring"
    namespace: "com.azure.ai.language.authoring"
    customization-class: customization/src/main/java/MyCustomization.java

Changelog

See changelog.

Troubleshooting

Enable logging in Java code

To enable logging, use tspconfig.yaml to add the loglevel: option. Typically, tspconfig.yaml file will be located in the same directory as the <target.tsp> file. The loglevel setting is a developer option and should be set under options->dev-options. The acceptable values for loglevel are off, debug, info, warn and error. A sample tspconfig.yaml is shown below that enables logging at info level. By default, logging is enabled at error level.

emit:
  - "@azure-tools/typespec-java"
options:
  "@azure-tools/typespec-java":
    emitter-output-dir: "{project-root}/tsp-output"
    namespace: "com.azure.ai.language.authoring"
    dev-options:
      loglevel: info

Debugging Java code

In order to set breakpoints and debug Java code locally on your development workspace, use the tspconfig.yaml file to set the debug option to true under options->dev-options as shown in the example below. If the debug option is set to true, then tsp compile <target.tsp> command will start the emitter which then invokes the Java process but the process will be suspended until a debugger is attached to the process. The process listens on port 5005. Run the remote debugger with this port on your IntelliJ or VS Code to connect to the Java process. This should now run the Java code generator and breaks at all applicable breakpoints.

The remote debugger configuration is shown below for reference.

emit:
  - "@azure-tools/typespec-java"
options:
  "@azure-tools/typespec-java":
    emitter-output-dir: "{project-root}/tsp-output"
    namespace: "com.azure.ai.language.authoring"
    dev-options:
      debug: true

New version of @typespec/compiler etc.

Force an installation of new version via deleting package-lock.json and node_modules in ./typespec-extension folder.

rm -rf node_modules
rm package-lock.json