feat: object mapper holder

Author: zihluwang

simple-jwt/src/main/java/com/onixbyte/jwt/holder/ObjectMapperHolder.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2024-2025 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.jwt.holder;
+
+import com.fasterxml.jackson.databind.MapperFeature;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.json.JsonMapper;
+
+import java.util.Objects;
+
+public class ObjectMapperHolder {
+
+    private static ObjectMapperHolder HOLDER;
+
+    private final ObjectMapper objectMapper;
+
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private ObjectMapperHolder() {
+        this.objectMapper = JsonMapper.builder()
+                .configure(MapperFeature.SORT_PROPERTIES_ALPHABETICALLY, true)
+                .build();
+    }
+
+    /**
+     * Get singleton instance.
+     *
+     * @return the {@code ObjectMapperHolder} instance
+     */
+    public static ObjectMapperHolder getInstance() {
+        if (Objects.isNull(HOLDER)) {
+            synchronized (ObjectMapperHolder.class) {
+                if (Objects.isNull(HOLDER)) {
+                    HOLDER = new ObjectMapperHolder();
+                }
+            }
+        }
+        return HOLDER;
+    }
+
+    /**
+     * Get Object
+     *
+     * @return
+     */
+    public ObjectMapper getObjectMapper() {
+        return objectMapper;
+    }
+}