feat(java): Include version headers in request options

fern/pages/changelogs/java-sdk/2025-01-07.mdx

@@ -0,0 +1,4 @@
+## 2.9.0
+**`(feat):`** Support version headers in request and client options.
+
+

generators/java/sdk/src/main/java/com/fern/java/client/ApiVersionConstants.java

@@ -0,0 +1,31 @@
+package com.fern.java.client;
+
+import com.fern.ir.model.commons.Name;
+import com.fern.ir.model.commons.SafeAndUnsafeString;
+
+public final class ApiVersionConstants {
+    /** Do not instantiate utils class. */
+    private ApiVersionConstants() {}
+
+    public static final String CURRENT_API_VERSION = "CURRENT";
+
+    public static final Name CURRENT_API_VERSION_NAME = Name.builder()
+            .originalName("CURRENT")
+            .camelCase(SafeAndUnsafeString.builder()
+                    .unsafeName("current")
+                    .safeName("current")
+                    .build())
+            .pascalCase(SafeAndUnsafeString.builder()
+                    .unsafeName("Current")
+                    .safeName("Current")
+                    .build())
+            .snakeCase(SafeAndUnsafeString.builder()
+                    .unsafeName("current")
+                    .safeName("current")
+                    .build())
+            .screamingSnakeCase(SafeAndUnsafeString.builder()
+                    .unsafeName("CURRENT")
+                    .safeName("CURRENT")
+                    .build())
+            .build();
+}

generators/java/sdk/src/main/java/com/fern/java/client/Cli.java

@@ -8,7 +8,11 @@
 import com.fern.ir.model.auth.AuthScheme;
 import com.fern.ir.model.auth.OAuthScheme;
 import com.fern.ir.model.commons.ErrorId;
+import com.fern.ir.model.commons.NameAndWireValue;
+import com.fern.ir.model.ir.HeaderApiVersionScheme;
 import com.fern.ir.model.ir.IntermediateRepresentation;
+import com.fern.ir.model.types.EnumTypeDeclaration;
+import com.fern.ir.model.types.EnumValue;
 import com.fern.java.AbstractGeneratorCli;
 import com.fern.java.AbstractPoetClassNameFactory;
 import com.fern.java.DefaultGeneratorExecClient;
@@ -32,6 +36,7 @@
 import com.fern.java.client.generators.SuppliersGenerator;
 import com.fern.java.client.generators.TestGenerator;
 import com.fern.java.generators.DateTimeDeserializerGenerator;
+import com.fern.java.generators.EnumGenerator;
 import com.fern.java.generators.ObjectMappersGenerator;
 import com.fern.java.generators.PaginationCoreGenerator;
 import com.fern.java.generators.StreamGenerator;
@@ -183,6 +188,30 @@ public GeneratedRootClient generateClient(
         GeneratedEnvironmentsClass generatedEnvironmentsClass = environmentGenerator.generateFile();
         this.addGeneratedFile(generatedEnvironmentsClass);
 
+        ir.getApiVersion()
+                .flatMap(apiVersion -> apiVersion.getHeader().map(HeaderApiVersionScheme::getValue))
+                .ifPresent(irDeclaration -> {
+                    EnumTypeDeclaration.Builder enumTypeDeclaration =
+                            EnumTypeDeclaration.builder().from(irDeclaration);
+
+                    irDeclaration.getDefault().ifPresent(defaultValue -> {
+                        enumTypeDeclaration.addValues(EnumValue.builder()
+                                .from(defaultValue)
+                                .name(NameAndWireValue.builder()
+                                        .from(defaultValue.getName())
+                                        .name(ApiVersionConstants.CURRENT_API_VERSION_NAME)
+                                        .build())
+                                .build());
+                    });
+
+                    EnumGenerator apiVersionsGenerator = new EnumGenerator(
+                            context.getPoetClassNameFactory().getApiVersionClassName(),
+                            context,
+                            enumTypeDeclaration.build());
+                    GeneratedJavaFile generatedApiVersions = apiVersionsGenerator.generateFile();
+                    this.addGeneratedFile(generatedApiVersions);
+                });
+
         RequestOptionsGenerator requestOptionsGenerator = new RequestOptionsGenerator(
                 context, context.getPoetClassNameFactory().getRequestOptionsClassName());
         GeneratedJavaFile generatedRequestOptions = requestOptionsGenerator.generateFile();

generators/java/sdk/src/main/java/com/fern/java/client/ClientPoetClassNameFactory.java

@@ -44,6 +44,10 @@ public ClassName getResponseBodyReaderClassName() {
         return ClassName.get(getCorePackage(), "ResponseBodyReader");
     }
 
+    public ClassName getApiVersionClassName() {
+        return ClassName.get(getCorePackage(), "ApiVersion");
+    }
+
     public ClassName getRequestOptionsClassName() {
         return ClassName.get(getCorePackage(), "RequestOptions");
     }

generators/java/sdk/src/main/java/com/fern/java/client/GeneratedClientOptions.java

@@ -22,6 +22,7 @@
 import com.squareup.javapoet.ClassName;
 import com.squareup.javapoet.MethodSpec;
 import java.util.Map;
+import java.util.Optional;
 import org.immutables.value.Value;
 
 @Value.Immutable
@@ -34,6 +35,8 @@ public abstract class GeneratedClientOptions extends AbstractGeneratedJavaFile {
 
     public abstract MethodSpec httpClientWithTimeout();
 
+    public abstract Optional<MethodSpec> version();
+
     public abstract Map<VariableId, MethodSpec> variableGetters();
 
     public abstract ClassName builderClassName();