updates javadocs, adds handling for 400 send request api server responses, adds possibility to pass any Object into message variables and headers

Author: sdiakovskyi-gd

src/main/java/com/mailjet/client/MailjetResponseUtil.java

@@ -16,6 +16,7 @@ public final class MailjetResponseUtil {
 	private static final int INTERNAL_SERVER_ERROR_STATUS = 500;
 	private static final int BAD_REQUEST_ERROR_STATUS = 400;
 	private static final int UNAUTHORIZED_STATUS = 401;
+	public static final int CREATED_STATUS = 201;
 
 	private static final String UNAUTHORIZED_MESSAGE = "Unauthorized. Please,verify your access key and access secret key or token for the given account";
 	private static final String TOO_MANY_REQUESTS_EXCEPTION = "Too Many Requests";
@@ -42,7 +43,7 @@ public static boolean isValidJSON(String json) {
 		return json != null && json.trim().startsWith("{") && json.trim().endsWith("}");
 	}
 
-	/*
+	/**
 	* Specific API methods support partial success
 	* like, if we send multiple emails in bulk
 	* and the one is failed and other one sent successfully

src/main/java/com/mailjet/client/helpers/StringMapSerializer.java

@@ -0,0 +1,31 @@
+package com.mailjet.client.helpers;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+
+import java.lang.reflect.Type;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Serializes {@code Map<String, Object> as Map<String, String>}
+ * where String value is JSON representation of the value
+ */
+public class StringMapSerializer implements JsonSerializer<Map> {
+    @Override
+    public JsonElement serialize(Map map, Type type, JsonSerializationContext jsonSerializationContext) {
+        Map<String, String> stringMap = new HashMap<>(map.size());
+
+        for (Object entry: map.entrySet()) {
+            Map.Entry<String, Object> objectEntry = (Map.Entry<String, Object>) entry;
+
+            String key = objectEntry.getKey();
+            String value = jsonSerializationContext.serialize(objectEntry.getValue()).toString();
+
+            stringMap.put(key, value);
+        }
+
+        return jsonSerializationContext.serialize(stringMap);
+    }
+}

src/main/java/com/mailjet/client/transactional/SendEmailsRequest.java

@@ -1,11 +1,11 @@
 package com.mailjet.client.transactional;
 
-import com.google.gson.FieldNamingPolicy;
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
+import com.google.gson.*;
 import com.mailjet.client.MailjetClient;
 import com.mailjet.client.MailjetRequest;
 import com.mailjet.client.MailjetResponse;
+import com.mailjet.client.MailjetResponseUtil;
+import com.mailjet.client.errors.MailjetClientRequestException;
 import com.mailjet.client.errors.MailjetException;
 import com.mailjet.client.resource.Emailv31;
 import com.mailjet.client.transactional.response.SendEmailsResponse;
@@ -18,6 +18,10 @@
 @Builder
 public class SendEmailsRequest {
 
+    private final static Gson gson = new GsonBuilder()
+            .setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)
+            .create();
+
     /**
      * Adds message to sent to the request
      * You can send up to 50 messages per batch
@@ -40,12 +44,12 @@ public class SendEmailsRequest {
      * Note: Max 50 emails per batch allowed
      * @param mailjetClient the Mailjet client that will be used to send messages
      * @return A response with sent messages information, or error information
-     * @throws MailjetException in case of communication error
+     * @throws MailjetException in case of communication error in HTTP stack,
+     * like, TLS connection couldn't be established to the Mailjet server
+     * Or the Server returned 5xx error,
+     * Or the Server returned the generic error response
      */
     public SendEmailsResponse sendWith(MailjetClient mailjetClient) throws MailjetException {
-        Gson gson = new GsonBuilder()
-                .setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)
-                .create();
 
         MailjetRequest request = new MailjetRequest(Emailv31.resource);
         request.setBody(gson.toJson(this));
@@ -56,6 +60,11 @@ public SendEmailsResponse sendWith(MailjetClient mailjetClient) throws MailjetEx
 
         SendEmailsResponse typedResponse = gson.fromJson(responseContent, SendEmailsResponse.class);
 
+        // in some cases, Mailjet server returns generic error w/o parsing the real passed messages
+        if (typedResponse.getMessages() == null && response.getStatus() != MailjetResponseUtil.CREATED_STATUS){
+            throw new MailjetClientRequestException(responseContent, response.getStatus());
+        }
+
         return typedResponse;
     }
 }

src/main/java/com/mailjet/client/transactional/TransactionalEmail.java

@@ -1,6 +1,8 @@
 package com.mailjet.client.transactional;
 
+import com.google.gson.annotations.JsonAdapter;
 import com.google.gson.annotations.SerializedName;
+import com.mailjet.client.helpers.StringMapSerializer;
 import lombok.Builder;
 import lombok.Singular;
 
@@ -177,16 +179,20 @@ public class TransactionalEmail {
 
     /**
      * Additional email headers.
+     * If the passed value type is not String, it will be serialized as a String with JSON representation of the passed object
      */
     @Singular
-    private Map<String, String> headers;
+    @JsonAdapter(StringMapSerializer.class)
+    private Map<String, Object> headers;
 
     /**
      * Adds variable used to modify the content of your email.
      * Specified as {var_name}:{var_value} pairs.
+     * If the passed value type is not String, it will be serialized as a String with JSON representation of the passed object
      * Enter the information in the template text / HTML part by using the [[var:{var_name}]] format.
      * Equivalent of using X-MJ-Vars header through SMTP.
      */
     @Singular
-    private Map<String, String> variables;
+    @JsonAdapter(StringMapSerializer.class)
+    private Map<String, Object> variables;
 }

src/test/java/com/mailjet/client/TransactionalEmailBuilderIT.java

@@ -1,5 +1,6 @@
 package com.mailjet.client;
 
+import com.mailjet.client.errors.MailjetClientRequestException;
 import com.mailjet.client.errors.MailjetException;
 import com.mailjet.client.transactional.*;
 import com.mailjet.client.transactional.response.MessageResult;
@@ -12,6 +13,7 @@
 
 import java.io.IOException;
 import java.nio.file.Paths;
+import java.util.LinkedList;
 
 
 public class TransactionalEmailBuilderIT {
@@ -42,6 +44,7 @@ public void SendEmailsRequest_SendsMessage() throws MailjetException, IOExceptio
                 .trackOpens(TrackOpens.ENABLED)
                 .attachment(Attachment.fromFile(attachmentPath))
                 .header("test-header-key", "test-value")
+                .variable("test-vars-array", new String[] {"a", "b", "c"})
                 .customID("custom-id-value")
                 .build();
 
@@ -94,4 +97,33 @@ public void SendEmailsRequest_InvalidToField_ReturnsAnError() throws MailjetExce
         Assert.assertEquals("\"invalid-email\" is an invalid email address.", error.getErrorMessage());
         Assert.assertEquals("To[0].Email", error.getErrorRelatedTo()[0]);
     }
+
+    @Test
+    public void SendEmailsRequest_MoreThan50MessagesPassed_ReturnsAnError() throws MailjetException, IOException {
+        // arrange
+        LinkedList<TransactionalEmail> messages = new LinkedList<>();
+
+        for (int i = 0; i < 51; i++) {
+            TransactionalEmail message = TransactionalEmail
+                    .builder()
+                    .to(new SendContact("test@mailjet.com"))
+                    .from(new SendContact(senderEmail, "Mailjet integration test"))
+                    .htmlPart("<h1>This is the HTML content of the mail</h1>")
+                    .subject("This is the subject")
+                    .build();
+
+            messages.add(message);
+        }
+
+        SendEmailsRequest request = SendEmailsRequest
+                .builder()
+                .messages(messages)
+                .build();
+
+        // act
+        MailjetClientRequestException exception = Assert.assertThrows(MailjetClientRequestException.class, () -> request.sendWith(client));
+
+        // assert
+        Assert.assertTrue(exception.getMessage().contains("Total number of recipients exceeded. Max allowed - 50"));
+    }
 }