RestResponse: Use HTTP status constants from HttpServletResponse

Use the HttpServletResponse constants, consistently with RestApiServlet,
instead of the ones from Apache's HttpStatus.

Also make RestApiServlet.SC_UNPROCESSABLE_ENTITY public so that can also
be referenced in RestResponse. (Note that HttpServletResponse doesn't
have this constant for some reason, but HttpStatus does). Also remove the
TODO in RestApiServlet; it's been there for years and it's not likely to
get added in the upstream HttpServletResponse soon.

Change-Id: I51e985892e192358acee951ffdb7c04ef87c34a9

java/com/google/gerrit/acceptance/RestResponse.java

@@ -17,13 +17,23 @@ package com.google.gerrit.acceptance;
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.google.gerrit.httpd.restapi.RestApiServlet.JSON_MAGIC;
+import static com.google.gerrit.httpd.restapi.RestApiServlet.SC_UNPROCESSABLE_ENTITY;
 import static java.nio.charset.StandardCharsets.UTF_8;
+import static javax.servlet.http.HttpServletResponse.SC_BAD_REQUEST;
+import static javax.servlet.http.HttpServletResponse.SC_CONFLICT;
+import static javax.servlet.http.HttpServletResponse.SC_CREATED;
+import static javax.servlet.http.HttpServletResponse.SC_FORBIDDEN;
+import static javax.servlet.http.HttpServletResponse.SC_METHOD_NOT_ALLOWED;
+import static javax.servlet.http.HttpServletResponse.SC_MOVED_TEMPORARILY;
+import static javax.servlet.http.HttpServletResponse.SC_NOT_FOUND;
+import static javax.servlet.http.HttpServletResponse.SC_NO_CONTENT;
+import static javax.servlet.http.HttpServletResponse.SC_OK;
+import static javax.servlet.http.HttpServletResponse.SC_PRECONDITION_FAILED;
 
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.net.URI;
-import org.apache.http.HttpStatus;
 
 public class RestResponse extends HttpResponse {
 
@@ -47,47 +57,47 @@ public class RestResponse extends HttpResponse {
   }
 
   public void assertOK() throws Exception {
-    assertStatus(HttpStatus.SC_OK);
+    assertStatus(SC_OK);
   }
 
   public void assertNotFound() throws Exception {
-    assertStatus(HttpStatus.SC_NOT_FOUND);
+    assertStatus(SC_NOT_FOUND);
   }
 
   public void assertConflict() throws Exception {
-    assertStatus(HttpStatus.SC_CONFLICT);
+    assertStatus(SC_CONFLICT);
   }
 
   public void assertForbidden() throws Exception {
-    assertStatus(HttpStatus.SC_FORBIDDEN);
+    assertStatus(SC_FORBIDDEN);
   }
 
   public void assertNoContent() throws Exception {
-    assertStatus(HttpStatus.SC_NO_CONTENT);
+    assertStatus(SC_NO_CONTENT);
   }
 
   public void assertBadRequest() throws Exception {
-    assertStatus(HttpStatus.SC_BAD_REQUEST);
+    assertStatus(SC_BAD_REQUEST);
   }
 
   public void assertUnprocessableEntity() throws Exception {
-    assertStatus(HttpStatus.SC_UNPROCESSABLE_ENTITY);
+    assertStatus(SC_UNPROCESSABLE_ENTITY);
   }
 
   public void assertMethodNotAllowed() throws Exception {
-    assertStatus(HttpStatus.SC_METHOD_NOT_ALLOWED);
+    assertStatus(SC_METHOD_NOT_ALLOWED);
   }
 
   public void assertCreated() throws Exception {
-    assertStatus(HttpStatus.SC_CREATED);
+    assertStatus(SC_CREATED);
   }
 
   public void assertPreconditionFailed() throws Exception {
-    assertStatus(HttpStatus.SC_PRECONDITION_FAILED);
+    assertStatus(SC_PRECONDITION_FAILED);
   }
 
   public void assertTemporaryRedirect(String path) throws Exception {
-    assertStatus(HttpStatus.SC_MOVED_TEMPORARILY);
+    assertStatus(SC_MOVED_TEMPORARILY);
     assertThat(URI.create(getHeader("Location")).getPath()).isEqualTo(path);
   }
 }

java/com/google/gerrit/httpd/restapi/RestApiServlet.java

@@ -195,9 +195,6 @@ public class RestApiServlet extends HttpServlet {
 
   @VisibleForTesting public static final String X_GERRIT_TRACE = "X-Gerrit-Trace";
 
-  // HTTP 422 Unprocessable Entity.
-  // TODO: Remove when HttpServletResponse.SC_UNPROCESSABLE_ENTITY is available
-  private static final int SC_UNPROCESSABLE_ENTITY = 422;
   private static final String X_REQUESTED_WITH = "X-Requested-With";
   private static final String X_GERRIT_AUTH = "X-Gerrit-Auth";
   static final ImmutableSet<String> ALLOWED_CORS_METHODS =
@@ -210,6 +207,7 @@ public class RestApiServlet extends HttpServlet {
   public static final String XD_AUTHORIZATION = "access_token";
   public static final String XD_CONTENT_TYPE = "$ct";
   public static final String XD_METHOD = "$m";
+  public static final int SC_UNPROCESSABLE_ENTITY = 422;
   public static final int SC_TOO_MANY_REQUESTS = 429;
 
   private static final int HEAP_EST_SIZE = 10 * 8 * 1024; // Presize 10 blocks.