refactor: Address Sonar findings (status constants, renderer complexity)

Author: thced

src/main/java/com/retailsvc/http/Response.java

@@ -1,5 +1,12 @@
 package com.retailsvc.http;
 
+import static java.net.HttpURLConnection.HTTP_ACCEPTED;
+import static java.net.HttpURLConnection.HTTP_CREATED;
+import static java.net.HttpURLConnection.HTTP_NOT_FOUND;
+import static java.net.HttpURLConnection.HTTP_NOT_IMPLEMENTED;
+import static java.net.HttpURLConnection.HTTP_NO_CONTENT;
+import static java.net.HttpURLConnection.HTTP_OK;
+
 import com.retailsvc.http.internal.BodyWriter;
 import java.io.IOException;
 import java.io.OutputStream;
@@ -33,7 +40,7 @@ public record Response(int status, Object body, String contentType, Map<String,
 
   /** {@code 204 No Content} with no body. */
   public static Response empty() {
-    return new Response(204, null, null, Map.of());
+    return new Response(HTTP_NO_CONTENT, null, null, Map.of());
   }
 
   /** Given status, no body. Use for {@code 200 OK} no body, {@code 404}, {@code 405}, etc. */
@@ -45,45 +52,45 @@ public static Response status(int status) {
 
   /** {@code 200 OK} with {@code body} serialised as JSON. */
   public static Response ok(Object body) {
-    return new Response(200, body, null, Map.of());
+    return new Response(HTTP_OK, body, null, Map.of());
   }
 
   /** {@code 201 Created} with {@code body} serialised as JSON. */
   public static Response created(Object body) {
-    return new Response(201, body, null, Map.of());
+    return new Response(HTTP_CREATED, body, null, Map.of());
   }
 
   /**
    * {@code 201 Created} with {@code body} as JSON and a {@code Location} header — the canonical
    * shape for a POST that creates a new resource.
    */
   public static Response created(Object body, String location) {
-    return new Response(201, body, null, Map.of("Location", location));
+    return new Response(HTTP_CREATED, body, null, Map.of("Location", location));
   }
 
   /** {@code 202 Accepted} with no body. Use for fire-and-forget async work. */
   public static Response accepted() {
-    return new Response(202, null, null, Map.of());
+    return new Response(HTTP_ACCEPTED, null, null, Map.of());
   }
 
   /** {@code 202 Accepted} with {@code body} serialised as JSON (typically a job/poll URL). */
   public static Response accepted(Object body) {
-    return new Response(202, body, null, Map.of());
+    return new Response(HTTP_ACCEPTED, body, null, Map.of());
   }
 
   /** {@code 404 Not Found} with no body. */
   public static Response notFound() {
-    return new Response(404, null, null, Map.of());
+    return new Response(HTTP_NOT_FOUND, null, null, Map.of());
   }
 
   /** {@code 404 Not Found} with {@code body} serialised as JSON (e.g. a ProblemDetail). */
   public static Response notFound(Object body) {
-    return new Response(404, body, null, Map.of());
+    return new Response(HTTP_NOT_FOUND, body, null, Map.of());
   }
 
   /** {@code 501 Not Implemented} with no body. */
   public static Response notImplemented() {
-    return new Response(501, null, null, Map.of());
+    return new Response(HTTP_NOT_IMPLEMENTED, null, null, Map.of());
   }
 
   /** {@code status} with {@code body} serialised by the content-type's {@link TypeMapper}. */

src/main/java/com/retailsvc/http/internal/ResponseRenderer.java

@@ -14,6 +14,7 @@ public final class ResponseRenderer {
 
   private static final String CONTENT_TYPE = "Content-Type";
   private static final String DEFAULT_JSON = "application/json";
+  private static final String OCTET_STREAM = "application/octet-stream";
 
   private final Map<String, TypeMapper> mappers;
 
@@ -31,47 +32,55 @@ public void render(HttpExchange exchange, Response response) throws IOException
 
       if (body == null) {
         exchange.sendResponseHeaders(status, -1);
-        return;
+      } else if (body instanceof BodyWriter writer) {
+        renderStream(exchange, headers, status, response.contentType(), writer);
+      } else {
+        renderBytes(exchange, headers, status, response.contentType(), body);
       }
+    }
+  }
 
-      if (body instanceof BodyWriter writer) {
-        long length = writer instanceof BodyWriter.Sized sized ? sized.length() : 0;
-        if (response.contentType() != null && !headers.containsKey(CONTENT_TYPE)) {
-          headers.add(CONTENT_TYPE, response.contentType());
-        }
-        exchange.sendResponseHeaders(status, length);
-        try (OutputStream out = exchange.getResponseBody()) {
-          writer.writeTo(out);
-        }
-        return;
-      }
+  private static void renderStream(
+      HttpExchange exchange, Headers headers, int status, String contentType, BodyWriter writer)
+      throws IOException {
+    if (contentType != null && !headers.containsKey(CONTENT_TYPE)) {
+      headers.add(CONTENT_TYPE, contentType);
+    }
+    long length = writer instanceof BodyWriter.Sized sized ? sized.length() : 0;
+    exchange.sendResponseHeaders(status, length);
+    try (OutputStream out = exchange.getResponseBody()) {
+      writer.writeTo(out);
+    }
+  }
 
-      byte[] bytes;
-      String contentType = response.contentType();
-      if (body instanceof byte[] raw) {
-        bytes = raw;
-        if (contentType == null) {
-          contentType = "application/octet-stream";
-        }
-      } else {
-        if (contentType == null) {
-          contentType = DEFAULT_JSON;
-        }
-        TypeMapper mapper = mappers.get(contentType.toLowerCase(Locale.ROOT));
-        if (mapper == null) {
-          throw new IllegalStateException("No TypeMapper registered for " + contentType);
-        }
-        bytes = mapper.writeTo(body);
-      }
-      if (!headers.containsKey(CONTENT_TYPE)) {
-        headers.add(CONTENT_TYPE, contentType);
-      }
-      exchange.sendResponseHeaders(status, bytes.length == 0 ? -1 : bytes.length);
-      if (bytes.length > 0) {
-        try (OutputStream out = exchange.getResponseBody()) {
-          out.write(bytes);
-        }
+  private void renderBytes(
+      HttpExchange exchange, Headers headers, int status, String contentType, Object body)
+      throws IOException {
+    byte[] bytes;
+    String effectiveContentType;
+    if (body instanceof byte[] raw) {
+      bytes = raw;
+      effectiveContentType = contentType != null ? contentType : OCTET_STREAM;
+    } else {
+      effectiveContentType = contentType != null ? contentType : DEFAULT_JSON;
+      bytes = serialize(body, effectiveContentType);
+    }
+    if (!headers.containsKey(CONTENT_TYPE)) {
+      headers.add(CONTENT_TYPE, effectiveContentType);
+    }
+    exchange.sendResponseHeaders(status, bytes.length == 0 ? -1 : bytes.length);
+    if (bytes.length > 0) {
+      try (OutputStream out = exchange.getResponseBody()) {
+        out.write(bytes);
       }
     }
   }
+
+  private byte[] serialize(Object body, String contentType) {
+    TypeMapper mapper = mappers.get(contentType.toLowerCase(Locale.ROOT));
+    if (mapper == null) {
+      throw new IllegalStateException("No TypeMapper registered for " + contentType);
+    }
+    return mapper.writeTo(body);
+  }
 }