feat: Support custom ObjectMappers, with singleton defaults

src/main/java/com/twilio/http/TwilioRestClient.java

@@ -51,14 +51,8 @@ protected TwilioRestClient(Builder b) {
         this.region = b.region;
         this.edge = b.edge;
         this.httpClient = b.httpClient;
-        this.objectMapper = new ObjectMapper();
+        this.objectMapper = b.objectMapper;
         this.userAgentExtensions = b.userAgentExtensions;
-
-        // This module configures the ObjectMapper to use
-        // public API methods for manipulating java.time.*
-        // classes. The alternative is to use reflection which
-        // generates warnings from the module system on Java 9+
-        objectMapper.registerModule(new JavaTimeModule());
     }
 
     /**
@@ -71,7 +65,7 @@ public Response request(final Request request) {
         if (username != null && password != null) {
             request.setAuth(username, password);
         } else if (authStrategy != null) {
-           request.setAuth(authStrategy);
+            request.setAuth(authStrategy);
         }
 
         if (region != null)
@@ -106,6 +100,13 @@ public Response request(final Request request) {
     }
 
     public static class Builder {
+        // This module configures the ObjectMapper to use
+        // public API methods for manipulating java.time.*
+        // classes. The alternative is to use reflection which
+        // generates warnings from the module system on Java 9+
+        private static final ObjectMapper DEFAULT_OBJECT_MAPPER = new ObjectMapper()
+            .registerModule(new JavaTimeModule());
+
         private String username;
         private String password;
         private AuthStrategy authStrategy;
@@ -114,6 +115,7 @@ public static class Builder {
         private String edge;
         private HttpClient httpClient;
         private List<String> userAgentExtensions;
+        private ObjectMapper objectMapper = DEFAULT_OBJECT_MAPPER;
 
         /**
          * Create a new Twilio Rest Client.
@@ -163,6 +165,11 @@ public Builder userAgentExtensions(final List<String> userAgentExtensions) {
             return this;
         }
 
+        public Builder objectMapper(final ObjectMapper objectMapper) {
+            this.objectMapper = objectMapper;
+            return this;
+        }
+
         /**
          * Build new TwilioRestClient.
          *

src/main/java/com/twilio/http/bearertoken/BearerTokenTwilioRestClient.java

@@ -44,23 +44,25 @@ private BearerTokenTwilioRestClient(BearerTokenTwilioRestClient.Builder b) {
         this.region = b.region;
         this.edge = b.edge;
         this.httpClient = b.httpClient;
-        this.objectMapper = new ObjectMapper();
+        this.objectMapper = b.objectMapper;
         this.userAgentExtensions = b.userAgentExtensions;
         this.tokenManager = b.tokenManager;
+    }
 
+    public static class Builder {
         // This module configures the ObjectMapper to use
         // public API methods for manipulating java.time.*
         // classes. The alternative is to use reflection which
         // generates warnings from the module system on Java 9+
-        objectMapper.registerModule(new JavaTimeModule());
-    }
-
-    public static class Builder {
+        private static final ObjectMapper DEFAULT_OBJECT_MAPPER = new ObjectMapper()
+            .registerModule(new JavaTimeModule());
+
         private String region;
         private String edge;
         private BearerTokenHttpClient httpClient;
         private List<String> userAgentExtensions;
         private TokenManager tokenManager;
+        private ObjectMapper objectMapper = DEFAULT_OBJECT_MAPPER;
 
         public Builder() {
             this.region = System.getenv("TWILIO_REGION");
@@ -95,6 +97,11 @@ public BearerTokenTwilioRestClient.Builder userAgentExtensions(final List<String
             return this;
         }
 
+        public BearerTokenTwilioRestClient.Builder objectMapper(final ObjectMapper objectMapper) {
+            this.objectMapper = objectMapper;
+            return this;
+        }
+
         public BearerTokenTwilioRestClient build() {
             if (this.httpClient == null) {
                 this.httpClient = new BearerTokenNetworkHttpClient();
@@ -111,7 +118,7 @@ public Response request(BearerTokenRequest request) {
                 }
             }
         }
-        
+
         request.setAuth(accessToken);
         if (region != null)
             request.setRegion(region);

src/main/java/com/twilio/http/noauth/NoAuthTwilioRestClient.java

@@ -38,21 +38,23 @@ private NoAuthTwilioRestClient(NoAuthTwilioRestClient.Builder b) {
         this.region = b.region;
         this.edge = b.edge;
         this.httpClient = b.httpClient;
-        this.objectMapper = new ObjectMapper();
+        this.objectMapper = b.objectMapper;
         this.userAgentExtensions = b.userAgentExtensions;
+    }
 
+    public static class Builder {
         // This module configures the ObjectMapper to use
         // public API methods for manipulating java.time.*
         // classes. The alternative is to use reflection which
         // generates warnings from the module system on Java 9+
-        objectMapper.registerModule(new JavaTimeModule());
-    }
-
-    public static class Builder {
+        private static final ObjectMapper DEFAULT_OBJECT_MAPPER = new ObjectMapper()
+            .registerModule(new JavaTimeModule());
+
         private String region;
         private String edge;
         private NoAuthNetworkHttpClient httpClient;
         private List<String> userAgentExtensions;
+        private ObjectMapper objectMapper = DEFAULT_OBJECT_MAPPER;
 
         public Builder() {
             this.region = System.getenv("TWILIO_REGION");
@@ -82,6 +84,11 @@ public NoAuthTwilioRestClient.Builder userAgentExtensions(final List<String> use
             return this;
         }
 
+        public NoAuthTwilioRestClient.Builder objectMapper(final ObjectMapper objectMapper) {
+            this.objectMapper = objectMapper;
+            return this;
+        }
+
         public NoAuthTwilioRestClient build() {
             if (this.httpClient == null) {
                 this.httpClient = new NoAuthNetworkHttpClient();

src/test/java/com/twilio/http/TwilioRestClientTest.java

@@ -1,18 +1,19 @@
 package com.twilio.http;
-import com.twilio.rest.Domains;
-import org.junit.Before;
-import org.junit.Test;
-import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import com.twilio.rest.Domains;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
-
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
 import static org.mockito.Mockito.when;
+import org.mockito.MockitoAnnotations;
 
 public class TwilioRestClientTest {
     private TwilioRestClient twilioRestClient;
@@ -48,6 +49,20 @@ public void testRequest() {
         assertNotNull(resp);
     }
 
+    @Test
+    public void testRequestWithCustomObjectMapper() {
+        Request request = new Request(
+                HttpMethod.GET,
+                Domains.API.toString(),
+                URI
+        );
+        twilioRestClientExtension = new TwilioRestClient.Builder(USER_NAME, TOKEN)
+                .objectMapper(new ObjectMapper().registerModule(new JavaTimeModule()))
+                .build();
+        twilioRestClientExtension.request(request);
+        assertEquals(userAgentStringExtensions, request.getUserAgentExtensions());
+    }
+
     @Test
     public void testRequestWithExtension() {
         Request request = new Request(