From f65986c720104551b572a15cb2ee4f581e627db9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20B=C3=89TI?= <jbeti@cosium.com>
Date: Fri, 16 Oct 2026 15:05:31 +0200
Subject: [PATCH] Map integer properties with int64 format to long

A JSON integer property declaring "format": "int64" is generated as
long when required, java.lang.Long otherwise. Integer properties without
this format keep mapping to int and java.lang.Integer.

Fixes #108
---
 README.md                                            |  2 ++
 .../JsonSchemaContent.java                           |  6 ++++++
 .../case1/Int64Properties.java                       | 12 ++++++++++++
 .../case1/customer.json                              | 10 +++++++++-
 4 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 tests/src/test/java/com/cosium/json_schema_to_java_record_tests/case1/Int64Properties.java

diff --git a/README.md b/README.md
index e27f197..21a6831 100644
--- a/README.md
+++ b/README.md
@@ -109,6 +109,8 @@ An annotation processor converting JSON schemas to java records.
 | array       |               |               | Immutable java.util.List |
 | number      |               | required      | double                   |
 | number      |               | non required  | java.lang.Double         |
+| integer     | int64         | required      | long                     |
+| integer     | int64         | non required  | java.lang.Long           |
 | integer     |               | required      | int                      |
 | integer     |               | non required  | java.lang.Integer        |
 | boolean     |               | required      | boolean                  |
diff --git a/core/src/main/java/com/cosium/json_schema_to_java_record/JsonSchemaContent.java b/core/src/main/java/com/cosium/json_schema_to_java_record/JsonSchemaContent.java
index 34f5a36..ecae76e 100644
--- a/core/src/main/java/com/cosium/json_schema_to_java_record/JsonSchemaContent.java
+++ b/core/src/main/java/com/cosium/json_schema_to_java_record/JsonSchemaContent.java
@@ -95,6 +95,12 @@ public TypeName writeJavaType(
             yield ClassName.get(Double.class);
           }
           case INTEGER -> {
+            if ("int64".equals(format)) {
+              if (preferPrimitive) {
+                yield TypeName.LONG;
+              }
+              yield ClassName.get(Long.class);
+            }
             if (preferPrimitive) {
               yield TypeName.INT;
             }
diff --git a/tests/src/test/java/com/cosium/json_schema_to_java_record_tests/case1/Int64Properties.java b/tests/src/test/java/com/cosium/json_schema_to_java_record_tests/case1/Int64Properties.java
new file mode 100644
index 0000000..e2ecd55
--- /dev/null
+++ b/tests/src/test/java/com/cosium/json_schema_to_java_record_tests/case1/Int64Properties.java
@@ -0,0 +1,12 @@
+package com.cosium.json_schema_to_java_record_tests.case1;
+
+import java.util.function.Function;
+
+/**
+ * Fails to compile if an int64 property is not generated as a long: an int would box to Integer.
+ */
+class Int64Properties {
+
+  static final Function<Customer, Long> REQUIRED = Customer::id;
+  static final Function<Customer, Long> NON_REQUIRED = Customer::referrerId;
+}
diff --git a/tests/src/test/resources/com/cosium/json_schema_to_java_record_tests/case1/customer.json b/tests/src/test/resources/com/cosium/json_schema_to_java_record_tests/case1/customer.json
index 772987a..4d2aa97 100644
--- a/tests/src/test/resources/com/cosium/json_schema_to_java_record_tests/case1/customer.json
+++ b/tests/src/test/resources/com/cosium/json_schema_to_java_record_tests/case1/customer.json
@@ -3,6 +3,14 @@
   "$id": "customer",
   "type": "object",
   "properties": {
+    "id": {
+      "type": "integer",
+      "format": "int64"
+    },
+    "referrerId": {
+      "type": "integer",
+      "format": "int64"
+    },
     "firstName": {
       "type": "string"
     },
@@ -19,5 +27,5 @@
       }
     }
   },
-  "required": [ "firstName", "lastName" ]
+  "required": [ "id", "firstName", "lastName" ]
 }
\ No newline at end of file