Function generateNamespaceApiFile

java/scripts/codegen/java.ts:1755–1870

* Generate a Java source file for a single namespace API class. * Returns the generated class name and whether a mapper static field is needed.

(
    prefix: string,
    namespacePath: string[],
    tree: NamespaceTree,
    isSession: boolean,
    packageName: string,
    packageDir: string
)

 * Returns the generated class name and whether a mapper static field is needed.
 */
async function generateNamespaceApiFile(
    prefix: string,
    namespacePath: string[],
    tree: NamespaceTree,
    isSession: boolean,
    packageName: string,
    packageDir: string
): Promise<string> {
    const className = apiClassName(prefix, namespacePath);
    const sessionIdExpr = "this.sessionId";

    const classLines: string[] = [];
    const allImports = new Set<string>([
        "java.util.concurrent.CompletableFuture",
        "javax.annotation.processing.Generated",
    ]);
    let needsMapper = false;

    // Generate sub-namespace fields
    const subFields: string[] = [];
    const subInits: string[] = [];
    for (const [subKey, subTree] of tree.subspaces) {
        const subClass = apiClassName(prefix, [...namespacePath, subKey]);
        subFields.push(`    /** API methods for the {@code ${[...namespacePath, subKey].join(".")}} sub-namespace. */`);
        subFields.push(`    public final ${subClass} ${subKey};`);
        if (isSession) {
            subInits.push(`        this.${subKey} = new ${subClass}(caller, sessionId);`);
        } else {
            subInits.push(`        this.${subKey} = new ${subClass}(caller);`);
        }
        // Recursively generate sub-namespace files
        await generateNamespaceApiFile(prefix, [...namespacePath, subKey], subTree, isSession, packageName, packageDir);
    }

    // Collect result/param imports and generate methods
    const methodLines: string[] = [];
    for (const [key, method] of tree.methods) {
        const resultClass = wrapperResultClassName(method);
        const paramsClass = wrapperParamsClassName(method);
        addWrapperResultImports(resultClass, allImports, packageName);
        if (paramsClass) allImports.add(`${packageName}.${paramsClass}`);

        const { lines, needsMapper: nm, needsExperimentalImport } = generateApiMethod(key, method, isSession, sessionIdExpr);
        methodLines.push(...lines);
        if (nm) needsMapper = true;
        if (needsExperimentalImport) allImports.add("com.github.copilot.CopilotExperimental");
    }

    // Build class body
    const qualifiedNs = namespacePath.length > 0 ? namespacePath.join(".") : prefix.toLowerCase();
    classLines.push(COPYRIGHT);
    classLines.push(``);
    classLines.push(AUTO_GENERATED_HEADER);
    classLines.push(GENERATED_FROM_API);
    classLines.push(``);
    classLines.push(`package ${packageName};`);
    classLines.push(``);