add builder pattern to java client and server

bin/configs/java-native.yaml

@@ -6,3 +6,4 @@ templateDir: modules/openapi-generator/src/main/resources/Java
 additionalProperties:
   artifactId: petstore-native
   hideGenerationTimestamp: "true"
+  generateBuilders: true

bin/configs/java-resttemplate.yaml

@@ -8,3 +8,4 @@ additionalProperties:
   hideGenerationTimestamp: "true"
   java8: true
   containerDefaultToNull: true
+  generateBuilders: true

bin/configs/spring-boot-3.yaml

@@ -11,3 +11,4 @@ additionalProperties:
   useBeanValidation: true
   withXml: true
   hideGenerationTimestamp: "true"
+  generateBuilders: true

bin/configs/spring-boot-useoptional.yaml

@@ -8,3 +8,4 @@ additionalProperties:
   useOptional: true
   artifactId: spring-boot-useoptional
   hideGenerationTimestamp: "true"
+  generateBuilders: true

bin/configs/spring-boot.yaml

@@ -9,3 +9,4 @@ additionalProperties:
   hideGenerationTimestamp: "true"
   camelCaseDollarSign: "true"
   modelNameSuffix: 'Dto'
+  generateBuilders: true

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

@@ -1125,5 +1125,10 @@ public boolean getIsEnum() {
     public void setIsEnum(boolean isEnum) {
         this.isEnum = isEnum;
     }
+
+
+    public boolean isExplode() {
+        return isExplode;
+    }
 }
 

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

@@ -87,6 +87,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
     public static final String JAVAX_PACKAGE = "javaxPackage";
     public static final String USE_JAKARTA_EE = "useJakartaEe";
     public static final String CONTAINER_DEFAULT_TO_NULL = "containerDefaultToNull";
+    public static final String GENERATE_BUILDERS = "generateBuilders";
 
     public static final String CAMEL_CASE_DOLLAR_SIGN = "camelCaseDollarSign";
     public static final String USE_ONE_OF_INTERFACES = "useOneOfInterfaces";
@@ -141,6 +142,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
     protected boolean camelCaseDollarSign = false;
     protected boolean useJakartaEe = false;
     protected boolean containerDefaultToNull = false;
+    protected boolean generateBuilders = false;
 
     private Map<String, String> schemaKeyToModelNameCache = new HashMap<>();
 
@@ -281,6 +283,7 @@ public AbstractJavaCodegen() {
         cliOptions.add(CliOption.newBoolean(CAMEL_CASE_DOLLAR_SIGN, "Fix camelCase when starting with $ sign. when true : $Value when false : $value"));
         cliOptions.add(CliOption.newBoolean(USE_JAKARTA_EE, "whether to use Jakarta EE namespace instead of javax"));
         cliOptions.add(CliOption.newBoolean(CONTAINER_DEFAULT_TO_NULL, "Set containers (array, set, map) default to null"));
+        cliOptions.add(CliOption.newBoolean(GENERATE_BUILDERS, "whether to create a builder in the models"));
 
         cliOptions.add(CliOption.newString(CodegenConstants.PARENT_GROUP_ID, CodegenConstants.PARENT_GROUP_ID_DESC));
         cliOptions.add(CliOption.newString(CodegenConstants.PARENT_ARTIFACT_ID, CodegenConstants.PARENT_ARTIFACT_ID_DESC));
@@ -567,6 +570,11 @@ public void processOpts() {
             this.setUseOneOfInterfaces(Boolean.parseBoolean(additionalProperties.get(USE_ONE_OF_INTERFACES).toString()));
         }
 
+        if (additionalProperties.containsKey(GENERATE_BUILDERS)) {
+            this.setGenerateBuilders(Boolean.parseBoolean(additionalProperties.get(GENERATE_BUILDERS).toString()));
+        }
+        writePropertyBack(GENERATE_BUILDERS, generateBuilders);
+
         if (!StringUtils.isEmpty(parentGroupId) && !StringUtils.isEmpty(parentArtifactId) && !StringUtils.isEmpty(parentVersion)) {
             additionalProperties.put("parentOverridden", true);
         }
@@ -668,11 +676,69 @@ public void processOpts() {
         additionalProperties.put(CONTAINER_DEFAULT_TO_NULL, containerDefaultToNull);
     }
 
+    public void setGenerateBuilders(boolean generateBuilders) {
+        this.generateBuilders = generateBuilders;
+    }
+
+    public boolean isGenerateBuilders() {
+        return generateBuilders;
+    }
+
+    /**
+     * Analyse and post process all Models.
+     *  Add parentVars to every Model which has a parent. This allows to generate
+     *  fluent setter methods for inherited properties.
+     * @param objs the models map.
+     * @return the processed models map.
+     */
     @Override
     public Map<String, ModelsMap> postProcessAllModels(Map<String, ModelsMap> objs) {
         objs = super.postProcessAllModels(objs);
         objs = super.updateAllModels(objs);
-
+        for (ModelsMap modelsAttrs : objs.values()) {
+            for (ModelMap mo : modelsAttrs.getModels()) {
+                CodegenModel codegenModel = mo.getModel();
+                Set<String> inheritedImports = new HashSet<>();
+                Map<String, CodegenProperty> propertyHash = new HashMap<>(codegenModel.vars.size());
+                for (final CodegenProperty property : codegenModel.vars) {
+                    propertyHash.put(property.name, property);
+                }
+                CodegenModel parentCodegenModel = codegenModel.parentModel;
+                while (parentCodegenModel != null) {
+                    for (final CodegenProperty property : parentCodegenModel.vars) {
+                        // helper list of parentVars simplifies templating
+                        if (!propertyHash.containsKey(property.name)) {
+                            propertyHash.put(property.name, property);
+                            final CodegenProperty parentVar = property.clone();
+                            parentVar.isInherited = true;
+                            LOGGER.info("adding parent variable {}", property.name);
+                            codegenModel.parentVars.add(parentVar);
+                            Set<String> imports = parentVar.getImports(true, this.importBaseType, generatorMetadata.getFeatureSet()).stream().filter(Objects::nonNull).collect(Collectors.toSet());
+                            for (String imp: imports) {
+                                // Avoid dupes
+                                if (!codegenModel.getImports().contains(imp)) {
+                                    inheritedImports.add(imp);
+                                    codegenModel.getImports().add(imp);
+                                }
+                            }
+                        }
+                    }
+                    parentCodegenModel = parentCodegenModel.getParentModel();
+                }
+                if (codegenModel.getParentModel() != null) {
+                    codegenModel.parentRequiredVars = new ArrayList<>(codegenModel.getParentModel().requiredVars);
+                }
+                // There must be a better way ...
+                for (String imp: inheritedImports) {
+                    String qimp = importMapping().get(imp);
+                    if (qimp != null) {
+                        Map<String,String> toAdd = new HashMap<>();
+                        toAdd.put("import", qimp);
+                        modelsAttrs.getImports().add(toAdd);
+                    }
+                }
+            }
+        }
         if (!additionalModelTypeAnnotations.isEmpty()) {
             for (String modelName : objs.keySet()) {
                 Map<String, Object> models = objs.get(modelName);

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

@@ -28,7 +28,6 @@
 import io.swagger.v3.oas.models.PathItem;
 import io.swagger.v3.oas.models.media.MediaType;
 import io.swagger.v3.oas.models.media.Schema;
-import io.swagger.v3.oas.models.parameters.Parameter;
 import io.swagger.v3.oas.models.servers.Server;
 import io.swagger.v3.oas.models.tags.Tag;
 import java.io.File;
@@ -1166,66 +1165,6 @@ public CodegenModel fromModel(String name, Schema model) {
         return codegenModel;
     }
 
-    /**
-     * Analyse and post process all Models.
-     *  Add parentVars to every Model which has a parent. This allows to generate
-     *  fluent setter methods for inherited properties.
-     * @param objs the models map.
-     * @return the processed models map.
-     */
-    @Override
-    public Map<String, ModelsMap> postProcessAllModels(Map<String, ModelsMap> objs) {
-        objs = super.postProcessAllModels(objs);
-        objs = super.updateAllModels(objs);
-
-        for (ModelsMap modelsAttrs : objs.values()) {
-            for (ModelMap mo : modelsAttrs.getModels()) {
-                CodegenModel codegenModel = mo.getModel();
-                Set<String> inheritedImports = new HashSet<>();
-                Map<String, CodegenProperty> propertyHash = new HashMap<>(codegenModel.vars.size());
-                for (final CodegenProperty property : codegenModel.vars) {
-                    propertyHash.put(property.name, property);
-                }
-                CodegenModel parentCodegenModel = codegenModel.parentModel;
-                while (parentCodegenModel != null) {
-                    for (final CodegenProperty property : parentCodegenModel.vars) {
-                        // helper list of parentVars simplifies templating
-                        if (!propertyHash.containsKey(property.name)) {
-                            propertyHash.put(property.name, property);
-                            final CodegenProperty parentVar = property.clone();
-                            parentVar.isInherited = true;
-                            LOGGER.info("adding parent variable {}", property.name);
-                            codegenModel.parentVars.add(parentVar);
-                            Set<String> imports = parentVar.getImports(true, this.importBaseType, generatorMetadata.getFeatureSet()).stream().filter(Objects::nonNull).collect(Collectors.toSet());
-                            for (String imp: imports) {
-                                // Avoid dupes
-                                if (!codegenModel.getImports().contains(imp)) {
-                                    inheritedImports.add(imp);
-                                    codegenModel.getImports().add(imp);
-                                }
-                            }
-                        }
-                    }
-                    parentCodegenModel = parentCodegenModel.getParentModel();
-                }
-                if (codegenModel.getParentModel() != null) {
-                    codegenModel.parentRequiredVars = new ArrayList<>(codegenModel.getParentModel().requiredVars);
-                }
-                // There must be a better way ...
-                for (String imp: inheritedImports) {
-                    String qimp = importMapping().get(imp);
-                    if (qimp != null) {
-                        Map<String,String> toAdd = new HashMap<>();
-                        toAdd.put("import", qimp);
-                        modelsAttrs.getImports().add(toAdd);
-                    }
-                }
-            }
-        }
-        return objs;
-    }
-
-
     /*
      * Add dynamic imports based on the parameters and vendor extensions of an operation.
      * The imports are expanded by the mustache {{import}} tag available to model and api

modules/openapi-generator/src/main/resources/Java/javaBuilder.mustache

@@ -0,0 +1,82 @@
+public static class Builder {{#parentModel}}extends {{classname}}.Builder {{/parentModel}}{
+
+    private {{classname}} instance;
+
+    public Builder() {
+      this(new {{classname}}());
+    }
+
+    protected Builder({{classname}} instance) {
+    {{#parentModel}}
+      super(instance);
+    {{/parentModel}}
+      this.instance = instance;
+    }
+
+    {{#vars}}
+    public {{classname}}.Builder {{name}}({{{datatypeWithEnum}}} {{name}}) {
+    {{#vendorExtensions.x-is-jackson-optional-nullable}}
+      this.instance.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{name}});
+    {{/vendorExtensions.x-is-jackson-optional-nullable}}
+    {{^vendorExtensions.x-is-jackson-optional-nullable}}
+      this.instance.{{name}} = {{name}};
+    {{/vendorExtensions.x-is-jackson-optional-nullable}}
+      return this;
+    }
+    {{#vendorExtensions.x-is-jackson-optional-nullable}}
+    public {{classname}}.Builder {{name}}(JsonNullable<{{{datatypeWithEnum}}}> {{name}}) {
+      this.instance.{{name}} = {{name}};
+      return this;
+    }
+    {{/vendorExtensions.x-is-jackson-optional-nullable}}
+    {{/vars}}
+
+{{#parentVars}}
+    public {{classname}}.Builder {{name}}({{{datatypeWithEnum}}} {{name}}) { // inherited: {{isInherited}}
+      super.{{name}}({{name}});
+      return this;
+   }
+    {{#vendorExtensions.x-is-jackson-optional-nullable}}
+    public {{classname}}.Builder {{name}}(JsonNullable<{{{datatypeWithEnum}}}> {{name}}) {
+      this.instance.{{name}} = {{name}};
+      return this;
+    }
+    {{/vendorExtensions.x-is-jackson-optional-nullable}}
+
+    {{/parentVars}}
+
+    /**
+    * returns a built {{classname}} instance.
+    *
+    * The builder is not reusable.
+    */
+    public {{classname}} build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused{{#parentModel}}
+        super.build();{{/parentModel}}
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static {{classname}}.Builder builder() {
+    return new {{classname}}.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public {{classname}}.Builder toBuilder() {
+    return new {{classname}}.Builder(){{#allVars}}
+      .{{name}}({{getter}}()){{/allVars}};
+  }

modules/openapi-generator/src/main/resources/Java/libraries/native/pojo.mustache

@@ -593,4 +593,8 @@ static {
   JSON.registerDiscriminator({{classname}}.class, "{{propertyBaseName}}", mappings);
 }
 {{/discriminator}}
+{{#generateBuilders}}
+
+    {{>javaBuilder}}
+{{/generateBuilders}}
 }

modules/openapi-generator/src/main/resources/Java/pojo.mustache

@@ -83,18 +83,18 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
   {{/vendorExtensions.x-field-extra-annotation}}
   {{#vendorExtensions.x-is-jackson-optional-nullable}}
   {{#isContainer}}
-  private JsonNullable<{{{datatypeWithEnum}}}> {{name}} = JsonNullable.<{{{datatypeWithEnum}}}>undefined();
+  {{#hasChildren}}protected{{/hasChildren}}{{^hasChildren}}private{{/hasChildren}} JsonNullable<{{{datatypeWithEnum}}}> {{name}} = JsonNullable.<{{{datatypeWithEnum}}}>undefined();
   {{/isContainer}}
   {{^isContainer}}
-  private JsonNullable<{{{datatypeWithEnum}}}> {{name}} = JsonNullable.<{{{datatypeWithEnum}}}>{{#defaultValue}}of({{{.}}}){{/defaultValue}}{{^defaultValue}}undefined(){{/defaultValue}};
+  {{#hasChildren}}protected{{/hasChildren}}{{^hasChildren}}private{{/hasChildren}} JsonNullable<{{{datatypeWithEnum}}}> {{name}} = JsonNullable.<{{{datatypeWithEnum}}}>{{#defaultValue}}of({{{.}}}){{/defaultValue}}{{^defaultValue}}undefined(){{/defaultValue}};
   {{/isContainer}}
   {{/vendorExtensions.x-is-jackson-optional-nullable}}
   {{^vendorExtensions.x-is-jackson-optional-nullable}}
   {{#isContainer}}
-  private {{{datatypeWithEnum}}} {{name}}{{#defaultValue}} = {{{.}}}{{/defaultValue}};
+  {{#hasChildren}}protected{{/hasChildren}}{{^hasChildren}}private{{/hasChildren}} {{{datatypeWithEnum}}} {{name}}{{#defaultValue}} = {{{.}}}{{/defaultValue}};
   {{/isContainer}}
   {{^isContainer}}
-  {{#isDiscriminator}}protected{{/isDiscriminator}}{{^isDiscriminator}}private{{/isDiscriminator}} {{{datatypeWithEnum}}} {{name}}{{#defaultValue}} = {{{.}}}{{/defaultValue}};
+  {{#hasChildren}}protected{{/hasChildren}}{{^hasChildren}}private{{/hasChildren}} {{{datatypeWithEnum}}} {{name}}{{#defaultValue}} = {{{.}}}{{/defaultValue}};
   {{/isContainer}}
   {{/vendorExtensions.x-is-jackson-optional-nullable}}
 
@@ -279,7 +279,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   {{/vars}}
   {{#parent}}
-  {{#allVars}}
+  {{#readWriteVars}}
   {{#isOverridden}}
   @Override
   public {{classname}} {{name}}({{{datatypeWithEnum}}} {{name}}) {
@@ -293,7 +293,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
   }
 
   {{/isOverridden}}
-  {{/allVars}}
+  {{/readWriteVars}}
   {{/parent}}
   @Override
   public boolean equals(Object o) {
@@ -613,5 +613,9 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
     }
   };
 {{/parcelableModel}}
+{{#generateBuilders}}
+
+  {{>javaBuilder}}
+{{/generateBuilders}}
 
 }