From 668b8f0b77038841c21145ae5359b7fff544aa72 Mon Sep 17 00:00:00 2001
From: Tapan Avasthi <tapan.k.avasthi@gmail.com>
Date: Sat, 27 May 2023 19:14:01 +0530
Subject: [PATCH] BAEL-6293: Add builder pattern for ObjectMapper creation
 (#14112)

Co-authored-by: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
---
 .../objectmapper/ObjectMapperBuilder.java     | 45 +++++++++++++++++++
 .../ObjectMapperBuilderUnitTest.java          | 44 ++++++++++++++++++
 2 files changed, 89 insertions(+)
 create mode 100644 jackson-simple/src/main/java/com/baeldung/jackson/objectmapper/ObjectMapperBuilder.java
 create mode 100644 jackson-simple/src/test/java/com/baeldung/jackson/objectmapper/ObjectMapperBuilderUnitTest.java

diff --git a/jackson-simple/src/main/java/com/baeldung/jackson/objectmapper/ObjectMapperBuilder.java b/jackson-simple/src/main/java/com/baeldung/jackson/objectmapper/ObjectMapperBuilder.java
new file mode 100644
index 0000000000..0810d68da5
--- /dev/null
+++ b/jackson-simple/src/main/java/com/baeldung/jackson/objectmapper/ObjectMapperBuilder.java
@@ -0,0 +1,45 @@
+package com.baeldung.jackson.objectmapper;
+
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
+import java.time.ZoneId;
+import java.util.TimeZone;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+
+public class ObjectMapperBuilder {
+    private boolean enableIndentation;
+    private boolean preserveOrder;
+    private DateFormat dateFormat;
+
+    public ObjectMapperBuilder enableIndentation() {
+        this.enableIndentation = true;
+        return this;
+    }
+
+    public ObjectMapperBuilder dateFormat() {
+        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm a z");
+        simpleDateFormat.setTimeZone(TimeZone.getTimeZone(ZoneId.of("Asia/Kolkata")));
+        this.dateFormat = simpleDateFormat;
+        return this;
+    }
+
+    public ObjectMapperBuilder preserveOrder(boolean order) {
+        this.preserveOrder = order;
+        return this;
+    }
+
+    public ObjectMapper build() {
+        ObjectMapper objectMapper = new ObjectMapper();
+
+        objectMapper.configure(SerializationFeature.INDENT_OUTPUT, this.enableIndentation);
+        objectMapper.setDateFormat(this.dateFormat);
+        if (this.preserveOrder) {
+            objectMapper.enable(SerializationFeature.ORDER_MAP_ENTRIES_BY_KEYS);
+        }
+
+        return objectMapper;
+    }
+
+}
\ No newline at end of file
diff --git a/jackson-simple/src/test/java/com/baeldung/jackson/objectmapper/ObjectMapperBuilderUnitTest.java b/jackson-simple/src/test/java/com/baeldung/jackson/objectmapper/ObjectMapperBuilderUnitTest.java
new file mode 100644
index 0000000000..355e86798d
--- /dev/null
+++ b/jackson-simple/src/test/java/com/baeldung/jackson/objectmapper/ObjectMapperBuilderUnitTest.java
@@ -0,0 +1,44 @@
+package com.baeldung.jackson.objectmapper;
+
+import java.util.Date;
+
+import org.junit.Test;
+import org.junit.jupiter.api.Assertions;
+
+import com.baeldung.jackson.objectmapper.dto.Car;
+import com.baeldung.jackson.objectmapper.dto.Request;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+public class ObjectMapperBuilderUnitTest {
+
+    ObjectMapper mapper = new ObjectMapperBuilder()
+      .enableIndentation()
+      .dateFormat()
+      .preserveOrder(true)
+      .build();
+
+    Car givenCar = new Car("White", "Sedan");
+    String givenCarJsonStr = "{ \"color\" : \"White\", \"type\" : \"Sedan\" }";
+
+    @Test
+    public void whenReadCarJsonStr_thenReturnCarObjectCorrectly() throws JsonProcessingException {
+        Car actual = mapper.readValue(givenCarJsonStr, Car.class);
+        Assertions.assertEquals("White", actual.getColor());
+        Assertions.assertEquals("Sedan", actual.getType());
+    }
+
+    @Test
+    public void whenWriteRequestObject_thenReturnRequestJsonStrCorrectly() throws JsonProcessingException {
+        Request request = new Request();
+        request.setCar(givenCar);
+        Date date = new Date(1684909857000L);
+        request.setDatePurchased(date);
+
+        String actual = mapper.writeValueAsString(request);
+        String expected = "{\n" + "  \"car\" : {\n" + "    \"color\" : \"White\",\n" +
+          "    \"type\" : \"Sedan\"\n" + "  },\n" + "  \"datePurchased\" : \"2023-05-24 12:00 PM IST\"\n" +
+          "}";
+        Assertions.assertEquals(expected, actual);
+    }
+}