feat: Add data residency for eu and global regions

Merging in feature branch

src/main/java/com/sendgrid/BaseInterface.java

@@ -17,6 +17,13 @@ public abstract class BaseInterface implements SendGridAPI {
   private static final int RATE_LIMIT_RESPONSE_CODE = 429;
   private static final int THREAD_POOL_SIZE = 8;
 
+  private static final Map<String, String> allowedRegionsHostMap;
+  static {
+    //todo: change this to Map.of() when we've moved on from Java 8
+    allowedRegionsHostMap = new HashMap<>();
+    allowedRegionsHostMap.put("eu", "api.eu.sendgrid.com");
+    allowedRegionsHostMap.put("global", "api.sendgrid.com");
+  }
   private ExecutorService pool;
 
   /**
@@ -336,4 +343,22 @@ public void run() {
       }
     });
   }
+
+  /*
+  * Client libraries contain setters for specifying region/edge.
+  * This allows support global and eu regions only. This set will likely expand in the future.
+  * Global should be the default
+  * Global region means the message should be sent through:
+  * HTTP: api.sendgrid.com
+  * EU region means the message should be sent through:
+  * HTTP: api.eu.sendgrid.com
+*/
+  public void setDataResidency(String region){
+      if (allowedRegionsHostMap.containsKey(region)){
+        this.host = allowedRegionsHostMap.get(region);
+      }
+      else{
+        throw new IllegalArgumentException("region can only be \"eu\" or \"global\"");
+      }
+    }
 }

src/test/java/com/sendgrid/SendGridTest.java

@@ -3242,4 +3242,50 @@ public void test_request_headers_override_sendgrid_object_headers() throws IOExc
     sg.api(request);
     verify(client).api(argThat((Request req) -> req.getHeaders().get("set-on-both").equals("456")));
   }
+
+  @Test
+  public void testSetResidency_happy_path_eu() {
+    SendGrid sg = new SendGrid(SENDGRID_API_KEY);
+    sg.setDataResidency("eu");
+    Assert.assertEquals(sg.getHost(), "api.eu.sendgrid.com");
+  }
+  @Test
+  public void testSetResidency_happy_path_global() {
+    SendGrid sg = new SendGrid(SENDGRID_API_KEY);
+    sg.setDataResidency("global");
+    Assert.assertEquals(sg.getHost(), "api.eu.sendgrid.com");
+  }
+
+
+  @Test
+  public void testSetResidency_override_host() {
+    SendGrid sg = new SendGrid(SENDGRID_API_KEY);
+    sg.setHost("api.new.com");
+    sg.setDataResidency("eu");
+    Assert.assertEquals(sg.getHost(), "api.eu.sendgrid.com");
+  }
+
+  @Test
+  public void testsetResidency_override_data_residency() {
+    SendGrid sg = new SendGrid(SENDGRID_API_KEY);
+    sg.setDataResidency("eu");
+    sg.setHost("api.new.com");
+    Assert.assertEquals(sg.getHost(), "api.new.com");
+  }
+
+  @Test (expected = IllegalArgumentException.class)
+  public void testsetResidency_incorrect_region() {
+    SendGrid sg = new SendGrid(SENDGRID_API_KEY);
+    sg.setDataResidency("foo");
+  }
+  @Test (expected = IllegalArgumentException.class)
+  public void testsetResidency_null_region(){
+    SendGrid sg = new SendGrid(SENDGRID_API_KEY);
+    sg.setDataResidency("");
+  }
+  @Test
+  public void testsetResidency_default_region() {
+    SendGrid sg = new SendGrid(SENDGRID_API_KEY);
+    Assert.assertEquals(sg.getHost(), "api.sendgrid.com");
+  }
 }