fluent, remove 404 in status code, for get/list

fluentnamer/src/main/java/com/azure/autorest/fluent/transformer/FluentTransformer.java

@@ -45,6 +45,7 @@ public CodeModel postTransform(CodeModel codeModel) {
         codeModel = new OperationNameNormalization().process(codeModel);
         codeModel = new ResourceTypeNormalization().process(codeModel);
         codeModel = new ErrorTypeNormalization().process(codeModel);
+        codeModel = new ResponseStatusCodeNormalization().process(codeModel);
         if (fluentJavaSettings.isResourcePropertyAsSubResource()) {
             codeModel = new ResourcePropertyNormalization().process(codeModel);
         }

fluentnamer/src/main/java/com/azure/autorest/fluent/transformer/ResponseStatusCodeNormalization.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License. See License.txt in the project root for license information.
+ */
+
+package com.azure.autorest.fluent.transformer;
+
+import com.azure.autorest.extension.base.model.codemodel.CodeModel;
+import com.azure.autorest.extension.base.model.codemodel.Response;
+import com.azure.autorest.fluent.util.Utils;
+import com.azure.core.http.HttpMethod;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+public class ResponseStatusCodeNormalization {
+
+    private static final Logger logger = LoggerFactory.getLogger(ResponseStatusCodeNormalization.class);
+
+    private static final boolean REMOVE_404_IN_GET_RESPONSE = true;
+
+    public CodeModel process(CodeModel codeModel) {
+        codeModel.getOperationGroups().stream().flatMap(og -> og.getOperations().stream())
+                // only for GET method
+                .filter(o -> o.getRequests().stream()
+                        .anyMatch(r -> r.getProtocol() != null && r.getProtocol().getHttp() != null
+                                && HttpMethod.GET.name().equalsIgnoreCase(r.getProtocol().getHttp().getMethod())))
+                .forEach(operation -> {
+                    List<Response> responsesToRemove = new ArrayList<>();
+                    for (Response response : operation.getResponses()) {
+                        if (response.getProtocol() != null && response.getProtocol().getHttp() != null && response.getProtocol().getHttp().getStatusCodes() != null) {
+                            if (response.getProtocol().getHttp().getStatusCodes().contains("404")) {
+                                logger.warn("Operation {} expect 404 status code, in group {}",
+                                        Utils.getJavaName(operation), Utils.getJavaName(operation.getOperationGroup()));
+
+                                if (REMOVE_404_IN_GET_RESPONSE) {
+                                    String operationNameInLower = Utils.getJavaName(operation).toLowerCase(Locale.ROOT);
+                                    if (operationNameInLower.startsWith("get") || operationNameInLower.startsWith("list")) {
+                                        logger.info("Remove 404 status code in operation {}, in group {}",
+                                                Utils.getJavaName(operation), Utils.getJavaName(operation.getOperationGroup()));
+                                        if (response.getProtocol().getHttp().getStatusCodes().size() == 1) {
+                                            // remove the response with only 404
+                                            responsesToRemove.add(response);
+                                        } else {
+                                            response.getProtocol().getHttp().getStatusCodes().remove("404");
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                    if (!responsesToRemove.isEmpty()) {
+                        operation.getResponses().removeAll(responsesToRemove);
+                    }
+                });
+
+        return codeModel;
+    }
+}