[Java][Native] Support oneOf/anyOf schemas (#7263)

* Java-native add models of oneOf/anyOf

* Java-native refresh samples

* Java-native add a sample project for openapi3

Author: bgong-mdsol

bin/configs/java-native-openapi3.yaml

@@ -0,0 +1,11 @@
+generatorName: java
+outputDir: samples/openapi3/client/petstore/java/native
+library: native
+inputSpec: modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml
+templateDir: modules/openapi-generator/src/main/resources/Java
+additionalProperties:
+  artifactId: petstore-openapi3-native
+  hideGenerationTimestamp: true
+  serverPort: "8082"
+  useOneOfDiscriminatorLookup: true
+  disallowAdditionalPropertiesIfNotPresent: false

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

@@ -418,6 +418,8 @@ public void processOpts() {
             setJava8Mode(true);
             additionalProperties.put("java8", "true");
             supportingFiles.add(new SupportingFile("ApiResponse.mustache", invokerFolder, "ApiResponse.java"));
+            supportingFiles.add(new SupportingFile("JSON.mustache", invokerFolder, "JSON.java"));
+            supportingFiles.add(new SupportingFile("AbstractOpenApiSchema.mustache", (sourceFolder + File.separator + modelPackage().replace('.', File.separatorChar)).replace('/', File.separatorChar), "AbstractOpenApiSchema.java"));
             forceSerializationLibrary(SERIALIZATION_LIBRARY_JACKSON);
         } else if (RESTEASY.equals(getLibrary())) {
             supportingFiles.add(new SupportingFile("JSON.mustache", invokerFolder, "JSON.java"));
@@ -536,8 +538,8 @@ public void processOpts() {
         if (SERIALIZATION_LIBRARY_JACKSON.equals(getSerializationLibrary())) {
             additionalProperties.put(SERIALIZATION_LIBRARY_JACKSON, "true");
             additionalProperties.remove(SERIALIZATION_LIBRARY_GSON);
+            supportingFiles.add(new SupportingFile("RFC3339DateFormat.mustache", invokerFolder, "RFC3339DateFormat.java"));
             if (!NATIVE.equals(getLibrary())) {
-                supportingFiles.add(new SupportingFile("RFC3339DateFormat.mustache", invokerFolder, "RFC3339DateFormat.java"));
                 if ("threetenbp".equals(dateLibrary) && !usePlayWS) {
                     supportingFiles.add(new SupportingFile("CustomInstantDeserializer.mustache", invokerFolder, "CustomInstantDeserializer.java"));
                 }
@@ -822,7 +824,6 @@ public Map<String, Object> postProcessModels(Map<String, Object> objs) {
                     imports2Classnames.put("JsonNullable", "org.openapitools.jackson.nullable.JsonNullable");
                     imports2Classnames.put("NoSuchElementException", "java.util.NoSuchElementException");
                     imports2Classnames.put("JsonIgnore", "com.fasterxml.jackson.annotation.JsonIgnore");
-
                     for (Map.Entry<String, String> entry : imports2Classnames.entrySet()) {
                         cm.imports.add(entry.getKey());
                         Map<String, String> importsItem = new HashMap<String, String>();
@@ -838,7 +839,7 @@ public Map<String, Object> postProcessModels(Map<String, Object> objs) {
                 CodegenModel cm = (CodegenModel) mo.get("model");
 
                 cm.getVendorExtensions().putIfAbsent("x-implements", new ArrayList<String>());
-                if (JERSEY2.equals(getLibrary())) {
+                if (JERSEY2.equals(getLibrary()) || NATIVE.equals(getLibrary())) {
                     cm.getVendorExtensions().put("x-implements", new ArrayList<String>());
 
                     if (cm.oneOf != null && !cm.oneOf.isEmpty() && cm.oneOf.contains("ModelNull")) {
@@ -978,7 +979,6 @@ public void addImportsToOneOfInterface(List<Map<String, String>> imports) {
         for (String i : Arrays.asList("JsonSubTypes", "JsonTypeInfo")) {
             Map<String, String> oneImport = new HashMap<>();
             oneImport.put("import", importMapping.get(i));
-
             if (!imports.contains(oneImport)) {
                 imports.add(oneImport);
             }

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

@@ -0,0 +1,138 @@
+{{>licenseInfo}}
+
+package {{invokerPackage}}.model;
+
+import {{invokerPackage}}.ApiException;
+import java.util.Objects;
+import java.lang.reflect.Type;
+import java.util.Map;
+import javax.ws.rs.core.GenericType;
+
+import com.fasterxml.jackson.annotation.JsonValue;
+
+/**
+ * Abstract class for oneOf,anyOf schemas defined in OpenAPI spec
+ */
+{{>additionalModelTypeAnnotations}}{{>generatedAnnotation}}
+public abstract class AbstractOpenApiSchema {
+
+    // store the actual instance of the schema/object
+    private Object instance;
+
+    // is nullable
+    private Boolean isNullable;
+
+    // schema type (e.g. oneOf, anyOf)
+    private final String schemaType;
+
+    public AbstractOpenApiSchema(String schemaType, Boolean isNullable) {
+        this.schemaType = schemaType;
+        this.isNullable = isNullable;
+    }
+
+    /**
+     * Get the list of oneOf/anyOf composed schemas allowed to be stored in this object
+     *
+     * @return an instance of the actual schema/object
+     */
+    public abstract Map<String, GenericType> getSchemas();
+
+    /**
+     * Get the actual instance
+     *
+     * @return an instance of the actual schema/object
+     */
+    @JsonValue
+    public Object getActualInstance() {return instance;}
+
+    /**
+     * Set the actual instance
+     *
+     * @param instance the actual instance of the schema/object
+     */
+    public void setActualInstance(Object instance) {this.instance = instance;}
+
+    /**
+     * Get the instant recursively when the schemas defined in oneOf/anyof happen to be oneOf/anyOf schema as well
+     *
+     * @return an instance of the actual schema/object
+     */
+    public Object getActualInstanceRecursively() {
+        return getActualInstanceRecursively(this);
+    }
+
+    private Object getActualInstanceRecursively(AbstractOpenApiSchema object) {
+        if (object.getActualInstance() == null) {
+            return null;
+        } else if (object.getActualInstance() instanceof AbstractOpenApiSchema) {
+            return getActualInstanceRecursively((AbstractOpenApiSchema)object.getActualInstance());
+        } else {
+            return object.getActualInstance();
+        }
+    }
+
+    /**
+     * Get the schema type (e.g. anyOf, oneOf)
+     *
+     * @return the schema type
+     */
+    public String getSchemaType() {
+        return schemaType;
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append("class ").append(getClass()).append(" {\n");
+        sb.append("    instance: ").append(toIndentedString(instance)).append("\n");
+        sb.append("    isNullable: ").append(toIndentedString(isNullable)).append("\n");
+        sb.append("    schemaType: ").append(toIndentedString(schemaType)).append("\n");
+        sb.append("}");
+        return sb.toString();
+    }
+
+    /**
+     * Convert the given object to string with each line indented by 4 spaces
+     * (except the first line).
+     */
+    private String toIndentedString(Object o) {
+        if (o == null) {
+            return "null";
+        }
+        return o.toString().replace("\n", "\n    ");
+    }
+
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        AbstractOpenApiSchema a = (AbstractOpenApiSchema) o;
+        return Objects.equals(this.instance, a.instance) &&
+            Objects.equals(this.isNullable, a.isNullable) &&
+            Objects.equals(this.schemaType, a.schemaType);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(instance, isNullable, schemaType);
+    }
+
+    /**
+     * Is nullalble
+     *
+     * @return true if it's nullable
+     */
+    public Boolean isNullable() {
+        if (Boolean.TRUE.equals(isNullable)) {
+            return Boolean.TRUE;
+        } else {
+            return Boolean.FALSE;
+        }
+    }
+
+{{>libraries/native/additional_properties}}
+
+}

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

@@ -5,7 +5,7 @@ package {{invokerPackage}};
 import java.util.List;
 import java.util.Map;
 {{#caseInsensitiveResponseHeaders}}
-import java.util.Map.Entry;
+import java.util.Map.Entry;		
 import java.util.TreeMap;
 {{/caseInsensitiveResponseHeaders}}