Add additionalProperties to SchemaProperty

api/src/main/java/org/eclipse/microprofile/openapi/annotations/media/SchemaProperty.java

@@ -23,6 +23,8 @@
 import org.eclipse.microprofile.openapi.annotations.ExternalDocumentation;
 import org.eclipse.microprofile.openapi.annotations.enums.SchemaType;
 import org.eclipse.microprofile.openapi.annotations.extensions.Extension;
+import org.eclipse.microprofile.openapi.annotations.media.Schema.False;
+import org.eclipse.microprofile.openapi.annotations.media.Schema.True;
 
 /**
  * The SchemaProperty Object allows the definition of input and output data types nested within the
@@ -368,6 +370,32 @@
  **/
  boolean uniqueItems() default false;
 
+ /**
+ * Provides a Java class as implementation for additional properties that may be present in instances of this
+ * schema.
+ *
+ * <p>
+ * If no additional properties are allowed, the value of this property should be set to {@link False False.class}
+ * which will be rendered as boolean <code>false</code> in the resulting OpenAPI document.
+ *
+ * <p>
+ * The default value {@link Void Void.class} will result in no {@code additionalProperties} attribute being
+ * generated in the resulting OpenAPI document. The effective value in that case is {@code true} per the OpenAPI
+ * specification.
+ *
+ * <p>
+ * Implementations MAY ignore this property if this schema's {@linkplain #type() type} is not
+ * {@linkplain SchemaType#OBJECT OBJECT}, either explicitly or as derived by the placement of the annotation.
+ *
+ * @return a class that describes the allowable schema for additional properties not explicitly defined
+ *
+ * @since 4.0
+ *
+ * @see True
+ * @see False
+ */
+ Class<?> additionalProperties() default Void.class;
+
  /**
  * List of extensions to be added to the {@link org.eclipse.microprofile.openapi.models.media.Schema Schema} model
  * corresponding to the containing annotation.