Document all used vendor extensions in specific generator (#11797)

docs/generators/groovy.md

@@ -61,6 +61,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |testOutput|Set output folder for models and APIs tests| |${project.build.directory}/generated-test-sources/openapi|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/java-camel.md

@@ -95,6 +95,16 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |virtualService|Generates the virtual service. For more details refer - https://github.com/virtualansoftware/virtualan/wiki| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+|x-spring-paginated|Add org.springframework.data.domain.Pageable to controller method. Can be used to handle page & size query parameters|OPERATION|false
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/java-inflector.md

@@ -63,6 +63,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |testOutput|Set output folder for models and APIs tests| |${project.build.directory}/generated-test-sources/openapi|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/java-micronaut-client.md

@@ -69,6 +69,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useBeanValidation|Use BeanValidation API annotations| |true|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/java-micronaut-server.md

@@ -71,6 +71,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useBeanValidation|Use BeanValidation API annotations| |true|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/java-msf4j.md

@@ -69,6 +69,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useTags|use tags for creating interface and controller classnames| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/java-pkmst.md

@@ -70,6 +70,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 |zipkinUri|Zipkin URI| |null|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/java-play-framework.md

@@ -73,6 +73,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 |wrapCalls|Add a wrapper to each controller function to handle things like metrics, response modification, etc..| |true|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/java-undertow-server.md

@@ -63,6 +63,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |testOutput|Set output folder for models and APIs tests| |${project.build.directory}/generated-test-sources/openapi|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/java-vertx-web.md

@@ -63,6 +63,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |testOutput|Set output folder for models and APIs tests| |${project.build.directory}/generated-test-sources/openapi|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/java-vertx.md

@@ -66,6 +66,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |vertxSwaggerRouterVersion|Specify the version of the swagger router library| |null|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/java.md

@@ -84,6 +84,16 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useRxJava3|Whether to use the RxJava3 adapter with the retrofit2 library. IMPORTANT: This option has been deprecated.| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+|x-webclient-blocking|Specifies if method for specific operation should be blocking or non-blocking(ex: return `Mono<T>/Flux<T>` or `return T/List<T>/Set<T>` & execute `.block()` inside generated method)|OPERATION|false
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/jaxrs-cxf-cdi.md

@@ -76,6 +76,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useTags|use tags for creating interface and controller classnames| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/jaxrs-cxf-client.md

@@ -67,6 +67,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useLoggingFeatureForTests|Use Logging Feature for tests| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/jaxrs-cxf-extended.md

@@ -90,6 +90,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useWadlFeature|Use WADL Feature| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/jaxrs-cxf.md

@@ -85,6 +85,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useWadlFeature|Use WADL Feature| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/jaxrs-jersey.md

@@ -70,6 +70,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useTags|use tags for creating interface and controller classnames| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/jaxrs-resteasy-eap.md

@@ -70,6 +70,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useTags|use tags for creating interface and controller classnames| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/jaxrs-resteasy.md

@@ -69,6 +69,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useTags|use tags for creating interface and controller classnames| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/jaxrs-spec.md

@@ -76,6 +76,15 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useTags|use tags for creating interface and controller classnames| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/spring.md

@@ -88,6 +88,16 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |virtualService|Generates the virtual service. For more details refer - https://github.com/virtualansoftware/virtualan/wiki| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-discriminator-value|Used with model inheritance to specify value for discriminator that identifies current model|MODEL|
+|x-implements|Ability to specify interfaces that model must implements|MODEL|empty array
+|x-setter-extra-annotation|Custom annotation that can be specified over java setter for specific field|FIELD|When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value
+|x-spring-paginated|Add org.springframework.data.domain.Pageable to controller method. Can be used to handle page & size query parameters|OPERATION|false
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

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

@@ -24,6 +24,7 @@ import org.openapitools.codegen.CliOption;
 import org.openapitools.codegen.CodegenConfig;
 import org.openapitools.codegen.CodegenConfigLoader;
 import org.openapitools.codegen.GeneratorNotFoundException;
+import org.openapitools.codegen.VendorExtension;
 import org.openapitools.codegen.meta.FeatureSet;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -89,6 +90,10 @@ public class ConfigHelp extends OpenApiGeneratorCommand {
             "--markdown-header"}, title = "markdown header", description = "When format=markdown, include this option to write out markdown headers (e.g. for docusaurus).")
     private Boolean markdownHeader;
 
+    @Option(name = {
+        "--supported-vendor-extensions"}, title = "supported vendor extensions", description = "List supported vendor extensions")
+    private Boolean supportedVendorExtensions;
+
     @Option(name = {"--full-details"}, title = "full generator details", description = "displays CLI options as well as other configs/mappings (implies --instantiation-types, --reserved-words, --language-specific-primitives, --import-mappings, --feature-set)")
     private Boolean fullDetails;
 
@@ -108,6 +113,7 @@ public class ConfigHelp extends OpenApiGeneratorCommand {
             importMappings = Boolean.TRUE;
             featureSets = Boolean.TRUE;
             metadata = Boolean.TRUE;
+            supportedVendorExtensions = Boolean.TRUE;
         }
 
         try {
@@ -198,6 +204,27 @@ public class ConfigHelp extends OpenApiGeneratorCommand {
         });
     }
 
+    private void generateMdSupportedVendorExtensions(StringBuilder sb, CodegenConfig config) {
+        List<VendorExtension> supportedVendorExtensions = config.getSupportedVendorExtensions();
+        if (supportedVendorExtensions.isEmpty()) {
+            return;
+        }
+
+        sb
+            .append(newline).append("## SUPPORTED VENDOR EXTENSIONS").append(newline).append(newline)
+            .append("| Extension name | Description | Applicable for | Default value |").append(newline)
+            .append("| -------------- | ----------- | -------------- | ------------- |").append(newline);
+
+        supportedVendorExtensions.forEach(
+            extension -> sb.append("|").append(extension.getName())
+                .append("|").append(extension.getDescription())
+                .append("|").append(extension.getLevels().stream().map(Objects::toString).collect(Collectors.joining(", ")))
+                .append("|").append(extension.getDefaultValue())
+                .append(newline)
+        );
+        sb.append(newline);
+    }
+
     private void generateMdImportMappings(StringBuilder sb, CodegenConfig config) {
         sb.append(newline).append("## IMPORT MAPPING").append(newline).append(newline);
 
@@ -332,6 +359,10 @@ public class ConfigHelp extends OpenApiGeneratorCommand {
         generateMdConfigOptionsHeader(sb, config);
         generateMdConfigOptions(sb, config);
 
+        if (Boolean.TRUE.equals(supportedVendorExtensions)) {
+            generateMdSupportedVendorExtensions(sb, config);
+        }
+
         if (Boolean.TRUE.equals(importMappings)) {
             generateMdImportMappings(sb, config);
         }

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

@@ -305,13 +305,15 @@ public interface CodegenConfig {
 
     Schema unaliasSchema(Schema schema, Map<String, String> usedImportMappings);
 
-    public String defaultTemplatingEngine();
+    String defaultTemplatingEngine();
 
-    public GeneratorLanguage generatorLanguage();
+    GeneratorLanguage generatorLanguage();
 
     /*
     the version of the language that the generator implements
     For python 3.9.0, generatorLanguageVersion would be "3.9.0"
     */
-    public String generatorLanguageVersion();
+    String generatorLanguageVersion();
+
+    List<VendorExtension> getSupportedVendorExtensions();
 }

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

@@ -7407,5 +7407,8 @@ public class DefaultCodegen implements CodegenConfig {
         return null;
     }
 
-    ;
+    @Override
+    public List<VendorExtension> getSupportedVendorExtensions() {
+        return new ArrayList<>();
+    }
 }

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

@@ -0,0 +1,53 @@
+package org.openapitools.codegen;
+
+import java.util.Collections;
+import java.util.List;
+
+public enum VendorExtension {
+
+    X_IMPLEMENTS("x-implements", ExtensionLevel.MODEL, "Ability to specify interfaces that model must implements", "empty array"),
+    X_SPRING_PAGINATED("x-spring-paginated", ExtensionLevel.OPERATION, "Add org.springframework.data.domain.Pageable to controller method. Can be used to handle page & size query parameters", "false"),
+    X_DISCRIMINATOR_VALUE("x-discriminator-value", ExtensionLevel.MODEL, "Used with model inheritance to specify value for discriminator that identifies current model", ""),
+    X_SETTER_EXTRA_ANNOTATION("x-setter-extra-annotation", ExtensionLevel.FIELD, "Custom annotation that can be specified over java setter for specific field", "When field is array & uniqueItems, then this extension is used to add `@JsonDeserialize(as = LinkedHashSet.class)` over setter, otherwise no value"),
+    X_WEBCLIENT_BLOCKING("x-webclient-blocking", ExtensionLevel.OPERATION, "Specifies if method for specific operation should be blocking or non-blocking(ex: return `Mono<T>/Flux<T>` or `return T/List<T>/Set<T>` & execute `.block()` inside generated method)", "false")
+    ;
+
+    private final String name;
+    private final List<ExtensionLevel> levels;
+    private final String description;
+    private final String defaultValue;
+
+    VendorExtension(final String name, final List<ExtensionLevel> levels, final String description, final String defaultValue) {
+        this.name = name;
+        this.levels = levels;
+        this.description = description;
+        this.defaultValue = defaultValue;
+    }
+
+    VendorExtension(final String name, final ExtensionLevel level, final String description, final String defaultValue) {
+        this(name, Collections.singletonList(level), description, defaultValue);
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public List<ExtensionLevel> getLevels() {
+        return levels;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public String getDefaultValue() {
+        return defaultValue;
+    }
+
+    public enum ExtensionLevel {
+        FIELD,
+        MODEL,
+        OPERATION
+    }
+
+}

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

@@ -2002,4 +2002,12 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         }
     }
 
+    @Override
+    public List<VendorExtension> getSupportedVendorExtensions() {
+        List<VendorExtension> extensions = super.getSupportedVendorExtensions();
+        extensions.add(VendorExtension.X_DISCRIMINATOR_VALUE);
+        extensions.add(VendorExtension.X_IMPLEMENTS);
+        extensions.add(VendorExtension.X_SETTER_EXTRA_ANNOTATION);
+        return extensions;
+    }
 }

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

@@ -1059,4 +1059,11 @@ public class JavaClientCodegen extends AbstractJavaCodegen
             }
         }
     }
+
+    @Override
+    public List<VendorExtension> getSupportedVendorExtensions() {
+        List<VendorExtension> extensions = super.getSupportedVendorExtensions();
+        extensions.add(VendorExtension.X_WEBCLIENT_BLOCKING);
+        return extensions;
+    }
 }

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

@@ -48,6 +48,7 @@ import org.openapitools.codegen.CodegenResponse;
 import org.openapitools.codegen.CodegenSecurity;
 import org.openapitools.codegen.CodegenType;
 import org.openapitools.codegen.SupportingFile;
+import org.openapitools.codegen.VendorExtension;
 import org.openapitools.codegen.languages.features.BeanValidationFeatures;
 import org.openapitools.codegen.languages.features.DocumentationProviderFeatures;
 import org.openapitools.codegen.languages.features.OptionalFeatures;
@@ -983,4 +984,11 @@ public class SpringCodegen extends AbstractJavaCodegen
     public void setUseSwaggerUI(boolean useSwaggerUI) {
         this.useSwaggerUI = useSwaggerUI;
     }
+
+    @Override
+    public List<VendorExtension> getSupportedVendorExtensions() {
+        List<VendorExtension> extensions = super.getSupportedVendorExtensions();
+        extensions.add(VendorExtension.X_SPRING_PAGINATED);
+        return extensions;
+    }
 }