[okhttp-gson] Generate static validateJsonElement method in all Classes (#375)

Generates a static `validateJsonElement` method in all generated `enum` and `record` classes, when the `library` configuration is set to `okhttp-gson` (default `library`). This method is used by GSON to validate the object. Additionally, two static fields; `openapiFields` and `openapiRequiredFields`, will also be generated in all `record` classes, as these are used in the `validateJsonElement` method. This method _may_ also be referenced by other classes, most notably by generated `oneOf` interface classes, or by _supportingFiles_. However, please note that this release does **not** include support for `oneOf` / `anyOf` / `allOf`.

Author: Chrimle

CITATION.cff

@@ -5,6 +5,6 @@ authors:
   given-names: "Christopher"
   orcid: "https://orcid.org/0009-0002-1005-3942"
 title: "OpenAPI to Java Records Mustache Templates"
-version: 2.7.1
+version: 2.8.0
 date-released: 2025-01-06
 url: "https://github.com/Chrimle/openapi-to-java-records-mustache-templates"

README.md

@@ -37,7 +37,7 @@ The mustache templates are best acquired by importing the project as a dependenc
 <dependency>
     <groupId>io.github.chrimle</groupId>
     <artifactId>openapi-to-java-records-mustache-templates</artifactId>
-    <version>2.7.1</version>
+    <version>2.8.0</version>
 </dependency>
 ```
 It is **strongly recommended** to import the project as a dependency. It has officially been published to:

docs/index.md

@@ -32,7 +32,7 @@ The mustache templates are best acquired by importing the project as a dependenc
 <dependency>
     <groupId>io.github.chrimle</groupId>
     <artifactId>openapi-to-java-records-mustache-templates</artifactId>
-    <version>2.7.1</version>
+    <version>2.8.0</version>
 </dependency>
 ```
 It is **strongly recommended** to import the project as a dependency. It has officially been published to:

mustache-templates/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>io.github.chrimle</groupId>
         <artifactId>openapi-to-java-records-mustache-templates-parent</artifactId>
-        <version>2.7.1</version>
+        <version>2.8.0</version>
     </parent>
 
     <artifactId>openapi-to-java-records-mustache-templates</artifactId>

mustache-templates/src/main/resources/templates/modelEnum.mustache

@@ -26,6 +26,11 @@
     - This template is overriding an official 'openapi-generator-maven-plugin' template.
     - Generates an `enum` class.
 
+}}{{!
+}}{{#gson}}import java.io.IOException;
+import com.google.gson.JsonElement;
+
+{{/gson}}{{!
 }}{{#isUri}}import java.net.URI;
 
 {{/isUri}}{{>javadoc}}{{!
@@ -78,4 +83,17 @@
     }
     {{#enumUnknownDefaultCase}}{{#allowableValues}}{{#enumVars}}{{#-last}}return {{{name}}};{{/-last}}{{/enumVars}}{{/allowableValues}}{{/enumUnknownDefaultCase}}{{^enumUnknownDefaultCase}}throw new IllegalArgumentException("Unexpected value '" + value + "'");{{/enumUnknownDefaultCase}}
   }
+{{#gson}}
+
+  /**
+   * Validates the JSON Element and throws an exception if issues are found.
+   *
+   * @param jsonElement to validate.
+   * @throws IOException if the JSON Element is not a valid {{classname}} object.
+   */
+  public static void validateJsonElement(final JsonElement jsonElement) throws IOException {
+    final {{^isNumber}}{{{dataType}}}{{/isNumber}}{{#isNumber}}String{{/isNumber}} value = {{#isUri}}URI.create({{/isUri}}jsonElement.{{#isNumber}}getAsString(){{/isNumber}}{{#isInteger}}getAsInt(){{/isInteger}}{{#isUri}}getAsString()){{/isUri}}{{^isNumber}}{{^isInteger}}{{^isUri}}getAs{{{dataType}}}(){{/isUri}}{{/isInteger}}{{/isNumber}};
+    {{{datatypeWithEnum}}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}}.fromValue({{#isNumber}}new BigDecimal({{/isNumber}}value{{#isNumber}}){{/isNumber}});
+  }
+{{/gson}}
 }

mustache-templates/src/main/resources/templates/pojo.mustache

@@ -28,6 +28,17 @@
   Additional Context:
     - This template is overriding an official 'openapi-generator-maven-plugin' template.
 
+}}{{!
+    Imports needed for 'okhttp-gson'
+}}{{#gson}}{{!
+}}import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+{{/gson}}{{!
 }}{{>javadoc}}{{!
 }}{{#isDeprecated}}@Deprecated
 {{/isDeprecated}}{{!
@@ -44,6 +55,19 @@
     {{/-last}}{{/vars}}{{^serializableModel}}){{/serializableModel}}{{#serializableModel}}
   ) implements Serializable{{/serializableModel}} {
 {{>serializableModel}}
+{{#gson}}  /** A set containing the names of all instance fields defined in this class. */
+  public static final HashSet<String> openapiFields =
+      new HashSet<String>(
+          Set.of({{#allVars}}"{{baseName}}"{{^-last}},
+              {{/-last}}{{/allVars}}));
+
+  /** A set containing the names of all required fields defined in this class. */
+  public static final HashSet<String> openapiRequiredFields =
+      new HashSet<String>(
+          Set.of({{#requiredVars}}"{{baseName}}"{{^-last}},
+              {{/-last}}{{/requiredVars}}));
+
+{{/gson}}
   public {{classname}}(
       {{#vars}}@{{javaxPackage}}.annotation.{{#isNullable}}Nullable{{/isNullable}}{{^isNullable}}{{#defaultValue}}Nullable{{/defaultValue}}{{^defaultValue}}Nonnull{{/defaultValue}}{{/isNullable}} final {{{datatypeWithEnum}}} {{name}}{{^-last}},
       {{/-last}}{{/vars}}) { {{#vars}}
@@ -103,5 +127,87 @@
       }
       {{#enumUnknownDefaultCase}}{{#allowableValues}}{{#enumVars}}{{#-last}}return {{{name}}};{{/-last}}{{/enumVars}}{{/allowableValues}}{{/enumUnknownDefaultCase}}{{^enumUnknownDefaultCase}}throw new IllegalArgumentException("Unexpected value '" + value + "'");{{/enumUnknownDefaultCase}}
     }
+{{#gson}}
+
+    /**
+     * Validates the JSON Element and throws an exception if issues are found.
+     *
+     * @param jsonElement to validate.
+     * @throws IOException if the JSON Element is not a valid {{datatypeWithEnum}} object.
+     */
+    public static void validateJsonElement(final JsonElement jsonElement) throws IOException {
+      final {{^isNumber}}{{{dataType}}}{{/isNumber}}{{#isNumber}}String{{/isNumber}} value = {{#isUri}}URI.create({{/isUri}}jsonElement.{{#isNumber}}getAsString(){{/isNumber}}{{#isInteger}}getAsInt(){{/isInteger}}{{#isUri}}getAsString()){{/isUri}}{{^isNumber}}{{^isInteger}}{{^isUri}}getAs{{{dataType}}}(){{/isUri}}{{/isInteger}}{{/isNumber}};
+      {{{datatypeWithEnum}}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}}.fromValue({{#isNumber}}new BigDecimal({{/isNumber}}value{{#isNumber}}){{/isNumber}});
+    }
+{{/gson}}
   }{{/isEnum}}{{/vars}}
+{{#gson}}
+
+  /**
+   * Validates the JSON Element and throws an exception if issues are found.
+   *
+   * @param jsonElement to validate.
+   * @throws IOException if the JSON Element is not a valid {{classname}} object.
+   */
+  public static void validateJsonElement(final JsonElement jsonElement) throws IOException { {{#requiredVars}}{{#-first}}
+    if (jsonElement == null) {
+      throw new IllegalArgumentException(
+          String.format(
+              "The required field(s) %s in {{{classname}}} is not found in the empty JSON string",
+              {{classname}}.openapiRequiredFields.toString()));
+    }
+{{/-first}}{{/requiredVars}}{{!
+}}{{^hasChildren}}{{^isAdditionalPropertiesTrue}}
+    for (final String key : jsonElement.getAsJsonObject().keySet()) {
+      if (!{{classname}}.openapiFields.contains(key)) {
+        throw new IllegalArgumentException(
+            String.format(
+                "The field `%s` in the JSON string is not defined in the `{{classname}}` properties. JSON: %s",
+                key, jsonElement));
+      }
+    }
+{{/isAdditionalPropertiesTrue}}{{!
+}}{{#requiredVars}}{{#-first}}
+    for (final String requiredField : {{classname}}.openapiRequiredFields) {
+      if (jsonElement.getAsJsonObject().get(requiredField) == null) {
+        throw new IllegalArgumentException(
+            String.format(
+                "The required field `%s` is not found in the JSON string: %s",
+                requiredField, jsonElement));
+      }
+    }
+{{/-first}}{{/requiredVars}}{{/hasChildren}}{{!
+}}{{^discriminator}}{{#hasVars}}
+    final JsonObject jsonObj = jsonElement.getAsJsonObject();
+{{/hasVars}}{{!
+}}{{#vars}}{{^required}}
+    if (jsonObj.get("{{{baseName}}}") != null
+        && !jsonObj.get("{{{baseName}}}").isJsonNull()) { {{/required}}{{!
+}}{{^isModel}}{{^isEnumRef}}{{^isEnum}}
+{{^required}}  {{/required}}    if (!jsonObj.get("{{{baseName}}}").{{#isArray}}isJsonArray(){{/isArray}}{{^isContainer}}{{^isModel}}isJsonPrimitive(){{/isModel}}{{/isContainer}}) {
+{{^required}}  {{/required}}      throw new IllegalArgumentException(
+{{^required}}  {{/required}}          String.format(
+{{^required}}  {{/required}}              "Expected the field `{{{baseName}}}` to be {{#isArray}}an array{{/isArray}}{{^isArray}}a primitive type{{/isArray}} in the JSON string but got `%s`",
+{{^required}}  {{/required}}              jsonObj.get("{{{baseName}}}")));
+{{^required}}  {{/required}}    }{{!
+}}{{/isEnum}}{{/isEnumRef}}{{/isModel}}{{!
+}}{{#items.isModel}}
+{{^required}}  {{/required}}    for (final JsonElement element : jsonObj.getAsJsonArray("{{{baseName}}}").asList()) {
+{{^required}}  {{/required}}      {{{items.dataType}}}.validateJsonElement(element);
+{{^required}}  {{/required}}    }{{!
+}}{{/items.isModel}}{{!
+}}{{^isContainer}}{{#isModel}}
+{{^required}}  {{/required}}    {{{dataType}}}.validateJsonElement(jsonObj.get("{{{baseName}}}"));{{!
+}}{{/isModel}}{{/isContainer}}{{!
+}}{{#isEnum}}
+{{^required}}  {{/required}}    {{{datatypeWithEnum}}}.validateJsonElement(jsonObj.get("{{{baseName}}}"));{{!
+}}{{/isEnum}}{{!
+}}{{#isEnumRef}}
+{{^required}}  {{/required}}    {{{dataType}}}.validateJsonElement(jsonObj.get("{{{baseName}}}"));{{!
+}}{{/isEnumRef}}
+{{^required}}
+    }
+{{/required}}{{/vars}}{{/discriminator}}{{!
+}}  }
+{{/gson}}
 }

mustache-templates/target/classes/templates/generateBuilders.mustache

@@ -15,7 +15,7 @@
 
 }}{{!
   Source: openapi-to-java-records-mustache-templates
-  Version: 2.7.1
+  Version: 2.8.0
   Type: Custom
   Dependencies:
     - none

mustache-templates/target/classes/templates/javadoc.mustache

@@ -15,7 +15,7 @@
 
 }}{{!
   Source: openapi-to-java-records-mustache-templates
-  Version: 2.7.1
+  Version: 2.8.0
   Type: Custom
   Dependencies:
     - none

mustache-templates/target/classes/templates/licenseInfo.mustache

@@ -15,7 +15,7 @@
 
 }}{{!
   Source: openapi-to-java-records-mustache-templates
-  Version: 2.7.1
+  Version: 2.8.0
   Type: Override
   Dependencies:
     - none
@@ -39,6 +39,6 @@
  * openapi-to-java-records-mustache-templates. For further information,
  * questions, requesting features or reporting issues, please visit:
  * https://github.com/Chrimle/openapi-to-java-records-mustache-templates.
- * Generated with Version: 2.7.1
+ * Generated with Version: 2.8.0
  *
  */

mustache-templates/target/classes/templates/modelEnum.mustache

@@ -15,7 +15,7 @@
 
 }}{{!
   Source: openapi-to-java-records-mustache-templates
-  Version: 2.7.1
+  Version: 2.8.0
   Type: Override
   Dependencies:
     - `additionalEnumTypeAnnotations.mustache` (Official)
@@ -26,6 +26,11 @@
     - This template is overriding an official 'openapi-generator-maven-plugin' template.
     - Generates an `enum` class.
 
+}}{{!
+}}{{#gson}}import java.io.IOException;
+import com.google.gson.JsonElement;
+
+{{/gson}}{{!
 }}{{#isUri}}import java.net.URI;
 
 {{/isUri}}{{>javadoc}}{{!
@@ -78,4 +83,17 @@
     }
     {{#enumUnknownDefaultCase}}{{#allowableValues}}{{#enumVars}}{{#-last}}return {{{name}}};{{/-last}}{{/enumVars}}{{/allowableValues}}{{/enumUnknownDefaultCase}}{{^enumUnknownDefaultCase}}throw new IllegalArgumentException("Unexpected value '" + value + "'");{{/enumUnknownDefaultCase}}
   }
+{{#gson}}
+
+  /**
+   * Validates the JSON Element and throws an exception if issues are found.
+   *
+   * @param jsonElement to validate.
+   * @throws IOException if the JSON Element is not a valid {{classname}} object.
+   */
+  public static void validateJsonElement(final JsonElement jsonElement) throws IOException {
+    final {{^isNumber}}{{{dataType}}}{{/isNumber}}{{#isNumber}}String{{/isNumber}} value = {{#isUri}}URI.create({{/isUri}}jsonElement.{{#isNumber}}getAsString(){{/isNumber}}{{#isInteger}}getAsInt(){{/isInteger}}{{#isUri}}getAsString()){{/isUri}}{{^isNumber}}{{^isInteger}}{{^isUri}}getAs{{{dataType}}}(){{/isUri}}{{/isInteger}}{{/isNumber}};
+    {{{datatypeWithEnum}}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}}.fromValue({{#isNumber}}new BigDecimal({{/isNumber}}value{{#isNumber}}){{/isNumber}});
+  }
+{{/gson}}
 }