chore: added no content body (#753)

Author: sbansla

src/main/java/com/sendgrid/constant/ApplicationConstants.java

@@ -1,7 +1,15 @@
 package com.sendgrid.constant;
 
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+
 import java.util.function.Predicate;
 
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class ApplicationConstants {
+    public static final int HTTP_STATUS_CODE_CREATED = 201;
+    public static final int HTTP_STATUS_CODE_NO_CONTENT = 204;
+    public static final int HTTP_STATUS_CODE_OK = 200;
     public static final Predicate<Integer> SUCCESS = i -> i != null && i >= 200 && i < 400;
 }

src/main/java/com/sendgrid/constant/Config.java

@@ -1,5 +1,8 @@
 package com.sendgrid.constant;
 
+import lombok.experimental.UtilityClass;
+
+@UtilityClass
 public class Config {
     public static final String VERSION = "5.0.0-rc.0";
     public static final String JAVA_VERSION = System.getProperty("java.version");

src/main/java/com/sendgrid/http/ApiResponse.java

@@ -2,7 +2,6 @@
 
 import lombok.Getter;
 import org.apache.http.Header;
-import java.util.Map;
 import java.util.StringJoiner;
 
 public class ApiResponse<T> {
@@ -12,10 +11,10 @@ public class ApiResponse<T> {
     private T body;
     @Getter
     private Header[] headers;
-
+    public static final Void NO_CONTENT = null;
 
     public ApiResponse(int statusCode, Header[] headers) {
-        this.body = null;
+        this.body = (T) NO_CONTENT;
         this.headers = headers;
         this.statusCode = statusCode;
     }
@@ -30,8 +29,8 @@ public ApiResponse(int statusCode, T body, Header[] headers) {
     public String toString() {
         StringJoiner joiner = new StringJoiner(", ", ApiResponse.class.getSimpleName() + "(", ")");
         if (statusCode != null) joiner.add("statusCode=" + statusCode);
-        if (headers != null) joiner.add("headers=" + headers);
         if (body != null) joiner.add("body=" + body);
+        if (headers != null) joiner.add("headers=" + headers);
         return joiner.toString();
     }
 }

src/main/java/com/sendgrid/http/Request.java

@@ -72,7 +72,7 @@ public Builder addHeaderParam(String key, String value) {
          *  query:  If there is query parameter apart from limit and offset.
          *  It will be the responsibility of the client to build a compound query, encode it and pass it as a query parameter in the query field.
          */
-        public Builder addQueryParams(String key, String value) {
+        public Builder addQueryParam(String key, String value) {
             if (!queryParams.containsKey(key)) {
                 queryParams.put(key, new ArrayList<String>());
             }