[feat] Add a way to customize the client object mapper

src/main/java/org/zendesk/client/v2/Zendesk.java

@@ -40,6 +40,7 @@
 import org.asynchttpclient.Response;
 import org.asynchttpclient.request.body.multipart.FilePart;
 import org.asynchttpclient.request.body.multipart.StringPart;
+import org.jetbrains.annotations.VisibleForTesting;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.zendesk.client.v2.model.AgentRole;
@@ -165,7 +166,8 @@ private Zendesk(
       String username,
       String password,
       Map<String, String> headers,
-      int cbpPageSize) {
+      int cbpPageSize,
+      Function<ObjectMapper, ObjectMapper> objectMapperCustomizer) {
     this.logger = LoggerFactory.getLogger(Zendesk.class);
     this.closeClient = client == null;
     this.oauthToken = null;
@@ -188,15 +190,16 @@ private Zendesk(
     headers.putIfAbsent(USER_AGENT_HEADER, new DefaultUserAgent().toString());
     this.headers = Collections.unmodifiableMap(headers);
     this.cbpPageSize = cbpPageSize;
-    this.mapper = createMapper();
+    this.mapper = createMapper(objectMapperCustomizer);
   }
 
   private Zendesk(
       AsyncHttpClient client,
       String url,
       String oauthToken,
       Map<String, String> headers,
-      int cbpPageSize) {
+      int cbpPageSize,
+      Function<ObjectMapper, ObjectMapper> objectMapperCustomizer) {
     this.logger = LoggerFactory.getLogger(Zendesk.class);
     this.closeClient = client == null;
     this.realm = null;
@@ -212,7 +215,7 @@ private Zendesk(
     headers.putIfAbsent(USER_AGENT_HEADER, new DefaultUserAgent().toString());
     this.headers = Collections.unmodifiableMap(headers);
     this.cbpPageSize = cbpPageSize;
-    this.mapper = createMapper();
+    this.mapper = createMapper(objectMapperCustomizer);
   }
 
   //////////////////////////////////////////////////////////////////////
@@ -4206,7 +4209,19 @@ private TemplateUri getSearchUri(Map<String, Object> params, String query, Strin
     return templateUri;
   }
 
+  /**
+   * This method did not allow for any customization and its public visibility was likely only for
+   * tests. If you rely on it for some reason, please report a new issue to discuss options. To
+   * customize the ObjectMapper, use the {@link Builder#customizeObjectMapper(Function)} method.
+   */
+  @Deprecated(since = "1.3.0", forRemoval = true)
   public static ObjectMapper createMapper() {
+    return createMapper(Function.identity());
+  }
+
+  @VisibleForTesting
+  public static ObjectMapper createMapper(
+      Function<ObjectMapper, ObjectMapper> objectMapperCustomizer) {
     ObjectMapper mapper = new ObjectMapper();
     mapper.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
     mapper.enable(DeserializationFeature.READ_ENUMS_USING_TO_STRING);
@@ -4215,6 +4230,11 @@ public static ObjectMapper createMapper() {
     mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
     mapper.setDateFormat(new StdDateFormat());
     mapper.enable(DeserializationFeature.USE_LONG_FOR_INTS);
+    return objectMapperCustomizer.apply(mapper);
+  }
+
+  @VisibleForTesting
+  ObjectMapper getMapper() {
     return mapper;
   }
 
@@ -4279,11 +4299,13 @@ public static class Builder {
     private String token = null;
     private String oauthToken = null;
     private int cbpPageSize = DEFAULT_CBP_PAGE_SIZE;
+    private Function<ObjectMapper, ObjectMapper> objectMapperCustomizer;
     private final Map<String, String> headers;
 
     public Builder(String url) {
       this.url = url;
       this.headers = new HashMap<>();
+      objectMapperCustomizer = Function.identity();
     }
 
     public Builder setClient(AsyncHttpClient client) {
@@ -4339,13 +4361,30 @@ public Builder setCbpPageSize(int cbpPageSize) {
       return this;
     }
 
+    /**
+     * Customize the ObjectMapper used by this Zendesk client. Careful, the customizer function will
+     * be applied after the default configuration for this library.
+     *
+     * @param customizer a function that takes an ObjectMapper and returns a customized ObjectMapper
+     * @return this builder instance
+     * @since 1.3.0
+     */
+    public Builder customizeObjectMapper(Function<ObjectMapper, ObjectMapper> customizer) {
+      if (customizer != null) {
+        this.objectMapperCustomizer = customizer;
+      }
+      return this;
+    }
+
     public Zendesk build() {
       if (token != null) {
-        return new Zendesk(client, url, username + "/token", token, headers, cbpPageSize);
+        return new Zendesk(
+            client, url, username + "/token", token, headers, cbpPageSize, objectMapperCustomizer);
       } else if (oauthToken != null) {
-        return new Zendesk(client, url, oauthToken, headers, cbpPageSize);
+        return new Zendesk(client, url, oauthToken, headers, cbpPageSize, objectMapperCustomizer);
       }
-      return new Zendesk(client, url, username, password, headers, cbpPageSize);
+      return new Zendesk(
+          client, url, username, password, headers, cbpPageSize, objectMapperCustomizer);
     }
   }
 }

src/test/java/org/zendesk/client/v2/SearchTest.java

@@ -13,6 +13,7 @@
 import java.io.UnsupportedEncodingException;
 import java.util.Arrays;
 import java.util.Random;
+import java.util.function.Function;
 import org.apache.commons.text.RandomStringGenerator;
 import org.junit.After;
 import org.junit.Before;
@@ -46,7 +47,7 @@ public class SearchTest {
 
   private Zendesk client;
   // use a mapper that is identical to what the client will use
-  private ObjectMapper objectMapper = Zendesk.createMapper();
+  private ObjectMapper objectMapper = Zendesk.createMapper(Function.identity());
 
   @Before
   public void setUp() throws Exception {

src/test/java/org/zendesk/client/v2/UserTest.java

@@ -19,6 +19,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.function.Function;
 import org.apache.commons.text.RandomStringGenerator;
 import org.junit.After;
 import org.junit.Before;
@@ -50,7 +51,7 @@ public class UserTest {
 
   private Zendesk client;
   // use a mapper that is identical to what the client will use
-  private ObjectMapper objectMapper = Zendesk.createMapper();
+  private ObjectMapper objectMapper = Zendesk.createMapper(Function.identity());
 
   @Before
   public void setUp() throws Exception {

src/test/java/org/zendesk/client/v2/ZendeskTest.java

@@ -0,0 +1,26 @@
+package org.zendesk.client.v2;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import org.junit.Test;
+
+public class ZendeskTest {
+
+  @Test
+  public void customizeMapper() {
+    var builder = new Zendesk.Builder("dummy");
+    builder.customizeObjectMapper(
+        om -> om.setSerializationInclusion(JsonInclude.Include.NON_EMPTY));
+
+    try (var zd = builder.build()) {
+      var mapper = zd.getMapper();
+      assertThat(
+          mapper.getSerializationConfig().getDefaultPropertyInclusion(),
+          is(
+              JsonInclude.Value.construct(
+                  JsonInclude.Include.NON_EMPTY, JsonInclude.Include.NON_EMPTY)));
+    }
+  }
+}

src/test/java/org/zendesk/client/v2/model/LocaleTest.java

@@ -3,6 +3,7 @@
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.MatcherAssert.assertThat;
 
+import java.util.function.Function;
 import org.junit.Test;
 import org.zendesk.client.v2.Zendesk;
 
@@ -19,7 +20,7 @@ public void testLocaleDeserialization() throws Exception {
             + "\"updated_at\": \"2023-09-21T19:23:16Z\""
             + "}";
 
-    Locale locale = Zendesk.createMapper().readValue(json, Locale.class);
+    Locale locale = Zendesk.createMapper(Function.identity()).readValue(json, Locale.class);
 
     assertThat(locale.getUrl(), is("https://acme.zendesk.com/api/v2/locales/en-US.json"));
     assertThat(locale.getId(), is(1L));

src/test/java/org/zendesk/client/v2/model/StatusTest.java

@@ -5,6 +5,7 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.ObjectReader;
+import java.util.function.Function;
 import org.junit.Test;
 import org.zendesk.client.v2.Zendesk;
 
@@ -15,15 +16,15 @@
 public class StatusTest {
   @Test
   public void serializeAsLowercase() throws Exception {
-    ObjectMapper mapper = Zendesk.createMapper();
+    ObjectMapper mapper = Zendesk.createMapper(Function.identity());
     assertThat(
         mapper.writeValueAsString(Status.PENDING),
         is("\"" + Status.PENDING.name().toLowerCase() + "\""));
   }
 
   @Test
   public void deserializeFromLowercase() throws Exception {
-    ObjectMapper mapper = Zendesk.createMapper();
+    ObjectMapper mapper = Zendesk.createMapper(Function.identity());
     ObjectReader reader = mapper.readerFor(Status.class);
     assertThat(
         reader.readValue("\"" + Status.PENDING.name().toLowerCase() + "\""),

src/test/java/org/zendesk/client/v2/model/TicketTest.java

@@ -6,6 +6,7 @@
 import java.util.Calendar;
 import java.util.Date;
 import java.util.Random;
+import java.util.function.Function;
 import org.junit.Test;
 import org.zendesk.client.v2.Zendesk;
 
@@ -17,7 +18,7 @@ public class TicketTest {
 
   @Test
   public void serializeWithNullSafeUpdate() throws Exception {
-    ObjectMapper mapper = Zendesk.createMapper();
+    ObjectMapper mapper = Zendesk.createMapper(Function.identity());
     Ticket ticket = createSampleTicket();
     assertThat(mapper.writeValueAsString(ticket))
         .doesNotContain("\"safe_update\"")
@@ -26,7 +27,7 @@ public void serializeWithNullSafeUpdate() throws Exception {
 
   @Test
   public void serializeWithFalseSafeUpdate() throws Exception {
-    ObjectMapper mapper = Zendesk.createMapper();
+    ObjectMapper mapper = Zendesk.createMapper(Function.identity());
     Ticket ticket = createSampleTicket();
     ticket.setSafeUpdate(false);
     assertThat(mapper.writeValueAsString(ticket))
@@ -36,7 +37,7 @@ public void serializeWithFalseSafeUpdate() throws Exception {
 
   @Test
   public void serializeWithSafeUpdate() throws Exception {
-    ObjectMapper mapper = Zendesk.createMapper();
+    ObjectMapper mapper = Zendesk.createMapper(Function.identity());
     Ticket ticket = createSampleTicket();
     ticket.setSafeUpdate(true);
     assertThat(mapper.writeValueAsString(ticket))

src/test/java/org/zendesk/client/v2/model/TimeZoneTest.java

@@ -10,6 +10,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.function.Function;
 import org.apache.commons.text.RandomStringGenerator;
 import org.junit.*;
 import org.zendesk.client.v2.Zendesk;
@@ -31,7 +32,7 @@ public class TimeZoneTest {
   @Rule public WireMockClassRule zendeskApiMock = zendeskApiClass;
 
   private Zendesk client;
-  private final ObjectMapper objectMapper = Zendesk.createMapper();
+  private final ObjectMapper objectMapper = Zendesk.createMapper(Function.identity());
 
   @Before
   public void setUp() {