Add description for enum constants on parameters

endpoints-framework/src/main/java/com/google/api/server/spi/discovery/DiscoveryGenerator.java

@@ -21,6 +21,7 @@
 import com.google.api.server.spi.ObjectMapperUtil;
 import com.google.api.server.spi.Strings;
 import com.google.api.server.spi.TypeLoader;
+import com.google.api.server.spi.config.Description;
 import com.google.api.server.spi.config.annotationreader.ApiAnnotationIntrospector;
 import com.google.api.server.spi.config.model.ApiConfig;
 import com.google.api.server.spi.config.model.ApiKey;
@@ -349,9 +350,12 @@ private JsonSchema convertMethodParameter(
     if (parameterConfig.isEnum()) {
       List<String> enumValues = Lists.newArrayList();
       List<String> enumDescriptions = Lists.newArrayList();
-      for (Object enumConstant : type.getRawType().getEnumConstants()) {
-        enumValues.add(enumConstant.toString());
-        enumDescriptions.add("");  // not current supported in annotations
+      for (java.lang.reflect.Field field : type.getRawType().getFields()) {
+        if (field.isEnumConstant()) {
+          enumValues.add(field.getName());
+          Description description = field.getAnnotation(Description.class);
+          enumDescriptions.add(description == null ? "" : description.value());
+        }
       }
       schema.setEnum(enumValues);
       schema.setEnumDescriptions(enumDescriptions);

endpoints-framework/src/test/resources/com/google/api/server/spi/discovery/foo_with_description_endpoint.json

@@ -168,6 +168,19 @@
               "location": "query",
               "required": true,
               "type": "integer"
+            },
+            "enum": {
+              "description": "enum desc",
+              "enum": [
+                "VALUE1",
+                "VALUE2"
+              ],
+              "enumDescriptions": [
+                "description of value1",
+                "description of value2"
+              ],
+              "location": "query",
+              "type": "string"
             }
           },
           "path": "foos",

endpoints-framework/src/test/resources/com/google/api/server/spi/swagger/foo_with_description_endpoint.swagger

@@ -27,6 +27,17 @@
             "required": true,
             "type": "integer",
             "format": "int32"
+          },
+          {
+            "name": "enum",
+            "in": "query",
+            "description": "enum desc",
+            "required": false,
+            "type": "string",
+            "enum": [
+              "VALUE1",
+              "VALUE2"
+            ]
           }
         ],
         "responses": {

test-utils/src/main/java/com/google/api/server/spi/testing/FooDescriptionEndpoint.java

@@ -20,6 +20,7 @@
 import com.google.api.server.spi.config.ApiMethod.HttpMethod;
 import com.google.api.server.spi.config.Description;
 import com.google.api.server.spi.config.Named;
+import com.google.api.server.spi.config.Nullable;
 import com.google.api.server.spi.response.CollectionResponse;
 
 @Api(
@@ -51,7 +52,7 @@ public FooDescription deleteFoo(@Named("id") @Description("id desc") String id)
   }
   @ApiMethod(name = "foo.list", description = "list desc", path = "foos",
       httpMethod = HttpMethod.GET)
-  public CollectionResponse<FooDescription> listFoos(@Named("n") Integer n) {
+  public CollectionResponse<FooDescription> listFoos(@Named("n") Integer n, @Nullable @Named("enum") @Description("enum desc") TestEnumDescription testEnum) {
     return null;
   }
   @ApiMethod(name = "toplevel", path = "foos", httpMethod = HttpMethod.POST)