Add nameMapping option to Java client, server generators (#16103)

* add nameMapping to java codegen

* update doc

* update samples

* fix typo

* update toParamName

Author: wing328

bin/configs/java-okhttp-gson.yaml

@@ -3,6 +3,9 @@ outputDir: samples/client/petstore/java/okhttp-gson
 library: okhttp-gson
 inputSpec: modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-okhttp-gson.yaml
 templateDir: modules/openapi-generator/src/main/resources/Java
+nameMappings:
+  _type: underscoreType
+  type_: typeWithUnderscore
 additionalProperties:
   artifactId: petstore-okhttp-gson
   hideGenerationTimestamp: "true"

docs/customization.md

@@ -395,11 +395,34 @@ or
 --import-mappings Pet=my.models.MyPet --import-mappings Order=my.models.MyOrder
 ```
 
+## Name Mapping
+
+One can map the name of the property/parameter to something else. Consider the following schema:
+```
+    PropertyNameCollision:
+      properties:
+        _type:
+          type: string
+        type:
+          type: string
+        type_:
+          type: string
+      type: object
+```
+`_type`, `type`, `type_` will result in property name collision in the Java client generator for example. We can resolve the issue using `nameMappings` by mapping `_type` to `underscoreType`, `type_` to `typeWithUnderscore`.
+
+Here is an example to use `nameMappings` in CLI:
+```sh
+java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g java -i modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-okhttp-gson.yaml  -o /tmp/java2/ --name-mappings _type=underscoreType, type_=typeWithUnderscore
+```
+
+(Not all generators support this feature yet. Please open an issue (ticket) to let us know which generators you would like to have this feature enabled and we'll prioritize accordingly.)
+
 ## Schema Mapping
 
 One can map the schema to something else (e.g. external objects/models outside of the package) using the `schemaMappings` option, e.g. in CLI
 ```sh
-java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g java -i modules/openapi-generator/src/test/resources/3_0/type-alias.yaml -o /tmp/java2/ --schema-mapping TypeAlias=foo.bar.TypeAlias
+java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g java -i modules/openapi-generator/src/test/resources/3_0/type-alias.yaml -o /tmp/java2/ --schema-mappings TypeAlias=foo.bar.TypeAlias
 ```
 Another example (in conjunction with --type-mappings):
 ```sh

modules/openapi-generator-cli/src/main/java/org/openapitools/codegen/cmd/ConfigHelp.java

@@ -80,6 +80,9 @@ public class ConfigHelp extends OpenApiGeneratorCommand {
     @Option(name = {"--inline-schema-options"}, title = "inline schema options", description = "options for handling inline schemas in inline model resolver")
     private Boolean inlineSchemaOptions;
 
+    @Option(name = {"--name-mappings"}, title = "property/parameter name mappings", description = "displays the property/parameter name mappings (none)")
+    private Boolean nameMappings;
+
     @Option(name = {"--openapi-normalizer"}, title = "openapi normalizer rules", description = "displays the OpenAPI normalizer rules (none)")
     private Boolean openapiNormalizer;
 
@@ -497,6 +500,18 @@ private void generatePlainTextHelp(StringBuilder sb, CodegenConfig config) {
             sb.append(newline);
         }
 
+        if (Boolean.TRUE.equals(nameMappings)) {
+            sb.append(newline).append("PROPERTY, PARAMETER NAME MAPPING").append(newline).append(newline);
+            Map<String, String> map = config.nameMapping()
+                    .entrySet()
+                    .stream()
+                    .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (a, b) -> {
+                        throw new IllegalStateException(String.format(Locale.ROOT, "Duplicated options! %s and %s", a, b));
+                    }, TreeMap::new));
+            writePlainTextFromMap(sb, map, optIndent, optNestedIndent, "property, parameter name", "Mapped to");
+            sb.append(newline);
+        }
+
         if (Boolean.TRUE.equals(openapiNormalizer)) {
             sb.append(newline).append("OPENAPI NORMALIZER RULES").append(newline).append(newline);
             Map<String, String> map = config.openapiNormalizer()

modules/openapi-generator-cli/src/main/java/org/openapitools/codegen/cmd/Generate.java

@@ -182,11 +182,19 @@ public class Generate extends OpenApiGeneratorCommand {
     private List<String> inlineSchemaNameMappings = new ArrayList<>();
 
     @Option(
-            name = {"--inline-schema-optionss"},
+            name = {"--inline-schema-options"},
             title = "inline schema options",
-            description = "specifies the options for handling inline schemas in the inline model resolver.")
+            description = "specifies the options for handling inline schemas in the inline model resolver."
+                    + " Please refer to https://github.com/OpenAPITools/openapi-generator/blob/master/docs/customization.md for a list of options.")
     private List<String> inlineSchemaOptions = new ArrayList<>();
 
+    @Option(
+            name = {"--name-mappings"},
+            title = "property, parameter name mappings",
+            description = "specifies mappings between the property, parameter name and the new name in the format of param_name=paramName,prop_name=PropName."
+                    + " You can also have multiple occurrences of this option.")
+    private List<String> nameMappings = new ArrayList<>();
+
     @Option(
             name = {"--openapi-normalizer"},
             title = "OpenAPI normalizer rules",
@@ -467,6 +475,7 @@ public void execute() {
         applySchemaMappingsKvpList(schemaMappings, configurator);
         applyInlineSchemaNameMappingsKvpList(inlineSchemaNameMappings, configurator);
         applyInlineSchemaOptionsKvpList(inlineSchemaOptions, configurator);
+        applyNameMappingsKvpList(nameMappings, configurator);
         applyOpenAPINormalizerKvpList(openapiNormalizer, configurator);
         applyTypeMappingsKvpList(typeMappings, configurator);
         applyAdditionalPropertiesKvpList(additionalProperties, configurator);

modules/openapi-generator-core/src/main/java/org/openapitools/codegen/config/GeneratorSettings.java

@@ -53,6 +53,7 @@ public final class GeneratorSettings implements Serializable {
     private final Map<String, String> schemaMappings;
     private final Map<String, String> inlineSchemaNameMappings;
     private final Map<String, String> inlineSchemaOptions;
+    private final Map<String, String> nameMappings;
     private final Map<String, String> openapiNormalizer;
     private final Set<String> languageSpecificPrimitives;
     private final Map<String, String> reservedWordsMappings;
@@ -265,6 +266,15 @@ public Map<String, String> getInlineSchemaOptions() {
         return inlineSchemaOptions;
     }
 
+    /**
+     * Gets property, parameter name mappings between a property, parameter name and the new name.
+     *
+     * @return the property, parameter name mappings
+     */
+    public Map<String, String> getNameMappings() {
+        return nameMappings;
+    }
+
     /**
      * Gets OpenAPI normalizer rules
      *
@@ -392,6 +402,7 @@ private GeneratorSettings(Builder builder) {
         schemaMappings = Collections.unmodifiableMap(builder.schemaMappings);
         inlineSchemaNameMappings = Collections.unmodifiableMap(builder.inlineSchemaNameMappings);
         inlineSchemaOptions = Collections.unmodifiableMap(builder.inlineSchemaOptions);
+        nameMappings = Collections.unmodifiableMap(builder.nameMappings);
         openapiNormalizer = Collections.unmodifiableMap(builder.openapiNormalizer);
         languageSpecificPrimitives = Collections.unmodifiableSet(builder.languageSpecificPrimitives);
         reservedWordsMappings = Collections.unmodifiableMap(builder.reservedWordsMappings);
@@ -466,6 +477,7 @@ public GeneratorSettings() {
         schemaMappings = Collections.unmodifiableMap(new HashMap<>(0));
         inlineSchemaNameMappings = Collections.unmodifiableMap(new HashMap<>(0));
         inlineSchemaOptions = Collections.unmodifiableMap(new HashMap<>(0));
+        nameMappings = Collections.unmodifiableMap(new HashMap<>(0));
         openapiNormalizer = Collections.unmodifiableMap(new HashMap<>(0));
         languageSpecificPrimitives = Collections.unmodifiableSet(new HashSet<>(0));
         reservedWordsMappings = Collections.unmodifiableMap(new HashMap<>(0));
@@ -527,6 +539,9 @@ public static Builder newBuilder(GeneratorSettings copy) {
         if (copy.getInlineSchemaOptions() != null) {
             builder.inlineSchemaOptions.putAll(copy.getInlineSchemaOptions());
         }
+        if (copy.getNameMappings() != null) {
+            builder.nameMappings.putAll(copy.getNameMappings());
+        }
         if (copy.getOpenAPINormalizer() != null) {
             builder.openapiNormalizer.putAll(copy.getOpenAPINormalizer());
         }
@@ -572,6 +587,7 @@ public static final class Builder {
         private Map<String, String> schemaMappings;
         private Map<String, String> inlineSchemaNameMappings;
         private Map<String, String> inlineSchemaOptions;
+        private Map<String, String> nameMappings;
         private Map<String, String> openapiNormalizer;
         private Set<String> languageSpecificPrimitives;
         private Map<String, String> reservedWordsMappings;
@@ -593,6 +609,7 @@ public Builder() {
             schemaMappings = new HashMap<>();
             inlineSchemaNameMappings = new HashMap<>();
             inlineSchemaOptions = new HashMap<>();
+            nameMappings = new HashMap<>();
             openapiNormalizer = new HashMap<>();
             languageSpecificPrimitives = new HashSet<>();
             reservedWordsMappings = new HashMap<>();
@@ -914,6 +931,32 @@ public Builder withInlineSchemaNameMapping(String key, String value) {
             return this;
         }
 
+        /**
+         * Sets the {@code nameMappings} and returns a reference to this Builder so that the methods can be chained together.
+         *
+         * @param nameMappings the {@code nameMappings} to set
+         * @return a reference to this Builder
+         */
+        public Builder withNameMappings(Map<String, String> nameMappings) {
+            this.nameMappings = nameMappings;
+            return this;
+        }
+
+        /**
+         * Sets a single {@code nameMappings} and returns a reference to this Builder so that the methods can be chained together.
+         *
+         * @param key   A key for the name mapping
+         * @param value The value of name mapping
+         * @return a reference to this Builder
+         */
+        public Builder withNameMapping(String key, String value) {
+            if (this.nameMappings == null) {
+                this.nameMappings = new HashMap<>();
+            }
+            this.nameMappings.put(key, value);
+            return this;
+        }
+
         /**
          * Sets the {@code openapiNormalizer} and returns a reference to this Builder so that the methods can be chained together.
          *
@@ -1128,6 +1171,7 @@ public boolean equals(Object o) {
                 Objects.equals(getSchemaMappings(), that.getSchemaMappings()) &&
                 Objects.equals(getInlineSchemaNameMappings(), that.getInlineSchemaNameMappings()) &&
                 Objects.equals(getInlineSchemaOptions(), that.getInlineSchemaOptions()) &&
+                Objects.equals(getNameMappings(), that.getNameMappings()) &&
                 Objects.equals(getOpenAPINormalizer(), that.getOpenAPINormalizer()) &&
                 Objects.equals(getLanguageSpecificPrimitives(), that.getLanguageSpecificPrimitives()) &&
                 Objects.equals(getReservedWordsMappings(), that.getReservedWordsMappings()) &&
@@ -1160,6 +1204,7 @@ public int hashCode() {
                 getSchemaMappings(),
                 getInlineSchemaNameMappings(),
                 getInlineSchemaOptions(),
+                getNameMappings(),
                 getOpenAPINormalizer(),
                 getLanguageSpecificPrimitives(),
                 getReservedWordsMappings(),

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/extensions/OpenApiGeneratorGenerateExtension.kt

@@ -167,6 +167,11 @@ open class OpenApiGeneratorGenerateExtension(project: Project) {
      */
     val inlineSchemaOptions = project.objects.mapProperty<String, String>()
 
+    /**
+     * Specifies mappings between a property, parameter name and the new name
+     */
+    val nameMappings = project.objects.mapProperty<String, String>()
+
     /**
      * Specifies mappings (rules) in OpenAPI normalizer
      */

modules/openapi-generator-gradle-plugin/src/main/kotlin/org/openapitools/generator/gradle/plugin/tasks/GenerateTask.kt

@@ -272,6 +272,13 @@ open class GenerateTask @Inject constructor(private val objectFactory: ObjectFac
     @Input
     val inlineSchemaOptions = project.objects.mapProperty<String, String>()
 
+    /**
+     * Specifies mappings between the property, parameter name and the new name
+     */
+    @Optional
+    @Input
+    val nameMappings = project.objects.mapProperty<String, String>()
+
     /**
      * Specifies mappings (rules) in OpenAPI normalizer
      */
@@ -807,6 +814,12 @@ open class GenerateTask @Inject constructor(private val objectFactory: ObjectFac
                 }
             }
 
+            if (nameMappings.isPresent) {
+                nameMappings.get().forEach { entry ->
+                    configurator.addNameMapping(entry.key, entry.value)
+                }
+            }
+
             if (openapiNormalizer.isPresent) {
                 openapiNormalizer.get().forEach { entry ->
                     configurator.addOpenAPINormalizer(entry.key, entry.value)

modules/openapi-generator-maven-plugin/src/main/java/org/openapitools/codegen/plugin/CodeGenMojo.java

@@ -332,6 +332,12 @@ public class CodeGenMojo extends AbstractMojo {
     @Parameter(name = "inlineSchemaOptions", property = "openapi.generator.maven.plugin.inlineSchemaOptions")
     private List<String> inlineSchemaOptions;
 
+    /**
+     * A map of property, parameter  names and the new names
+     */
+    @Parameter(name = "nameMappings", property = "openapi.generator.maven.plugin.nameMappings")
+    private List<String> nameMappings;
+
     /**
      * A set of rules for OpenAPI normalizer
      */

modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConfig.java

@@ -147,6 +147,8 @@ public interface CodegenConfig {
 
     Map<String, String> inlineSchemaOption();
 
+    Map<String, String> nameMapping();
+
     Map<String, String> openapiNormalizer();
 
     Map<String, String> apiTemplateFiles();

modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java

@@ -164,6 +164,8 @@ public class DefaultCodegen implements CodegenConfig {
     protected Map<String, String> inlineSchemaNameMapping = new HashMap<>();
     // a map to store the inline schema naming conventions
     protected Map<String, String> inlineSchemaOption = new HashMap<>();
+    // a map to store the mapping between property, parameter name and the name provided by the user
+    protected Map<String, String> nameMapping = new HashMap<>();
     // a map to store the rules in OpenAPI Normalizer
     protected Map<String, String> openapiNormalizer = new HashMap<>();
     protected String modelPackage = "", apiPackage = "", fileSuffix;
@@ -1199,6 +1201,11 @@ public Map<String, String> inlineSchemaOption() {
         return inlineSchemaOption;
     }
 
+    @Override
+    public Map<String, String> nameMapping() {
+        return nameMapping;
+    }
+
     @Override
     public Map<String, String> openapiNormalizer() {
         return openapiNormalizer;