Function generatePolymorphicResultClass

java/scripts/codegen/java.ts:322–398

* Generate a polymorphic base class and variant subclasses for a discriminated union result type.

(
    className: string,
    schema: JSONSchema7,
    packageName: string,
    packageDir: string
)

 * Generate a polymorphic base class and variant subclasses for a discriminated union result type.
 */
async function generatePolymorphicResultClass(
    className: string,
    schema: JSONSchema7,
    packageName: string,
    packageDir: string
): Promise<void> {
    const anyOf = schema.anyOf as JSONSchema7[];
    const variants = resolveAnyOfVariants(anyOf);
    const discriminator = findDiscriminator(variants);

    if (!discriminator) {
        console.warn(`[codegen] Cannot find discriminator for ${className} — skipping polymorphic generation`);
        return;
    }

    // Collect variant info
    interface VariantInfo {
        discriminatorValue: string;
        variantClassName: string;
        schema: JSONSchema7;
    }

    const variantInfos: VariantInfo[] = [];
    for (const [discValue, { schema: variantSchema }] of discriminator.mapping) {
        const variantClassName = (variantSchema as JSONSchema7 & { title?: string }).title ?? `${className}${toPascalCase(discValue)}`;
        variantInfos.push({ discriminatorValue: discValue, variantClassName, schema: variantSchema });
    }

    // Generate the abstract base class
    const baseLines: string[] = [];
    baseLines.push(COPYRIGHT);
    baseLines.push("");
    baseLines.push(AUTO_GENERATED_HEADER);
    baseLines.push(GENERATED_FROM_API);
    baseLines.push("");
    baseLines.push(`package ${packageName};`);
    baseLines.push("");
    baseLines.push(`import com.fasterxml.jackson.annotation.JsonIgnoreProperties;`);
    baseLines.push(`import com.fasterxml.jackson.annotation.JsonSubTypes;`);
    baseLines.push(`import com.fasterxml.jackson.annotation.JsonTypeInfo;`);
    baseLines.push(`import javax.annotation.processing.Generated;`);
    baseLines.push("");
    if (schema.description) {
        baseLines.push(`/**`);
        baseLines.push(` * ${schema.description}`);
        baseLines.push(` *`);
        baseLines.push(` * @since 1.0.0`);
        baseLines.push(` */`);
    }
    baseLines.push(`@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "${discriminator.property}", visible = true)`);
    baseLines.push(`@JsonSubTypes({`);
    for (let i = 0; i < variantInfos.length; i++) {
        const v = variantInfos[i];
        const comma = i < variantInfos.length - 1 ? "," : "";
        baseLines.push(`    @JsonSubTypes.Type(value = ${v.variantClassName}.class, name = "${v.discriminatorValue}")${comma}`);
    }
    baseLines.push(`})`);
    baseLines.push(`@JsonIgnoreProperties(ignoreUnknown = true)`);