Faster XML Jackson usage in Portal Code and replacing it with Gson

Areas where Jackson is Used:

1.     Direct usage of Jackson by Portal code

2.     Indirect dependency through other packages

3.     Frameworks configured with Jackson like Spring Boot

Modules with direct dependency on Jackson package:

Portal-SDK:

1. epsdk-fw

2. epsdk-analytics

3. epsdk-app-common

4. epsdk-app-os

5. epsdk-core

6. epsdk-domain

7. epsdk-music

8. epsdk-workflow

9. epsdk-aaf

Portal:

1. Portal-BE-Common:

2. Portal-BE-OS:

3. Portal-widget-ms:

Packages used that have dependency on Jackson:

Portal-SDK:

1. org.elasticsearch:elasticsearch:jar – Not using this package anywhere in the code and can be removed, as confirmed by Sunder.

2. org.onap.portal.sdk:epsdk-music:jar

Portal:

1. com.orbitz.consul:consul-client:jar - Excluded the jacskon dependency for this package and ran the build. The build is successful, however this needs to tested with real time scenarios.

2. org.elasticsearch:elasticsearch:jar - Not using this package anywhere in the code and can be removed, as confirmed by Sunder

3. Spring Boot
   
   
   

Code Analysis:

1. Portal-SDK:   Approximately 60+ files that inculde fatserxml jackson excluding test files.

2. Portal: Approximately 60+ files that inculde fatserxml jackson excluding test files

Using Gson In our Code:

Gson Maven Dependency:

            <dependency>

                        <groupId>com.google.code.gson</groupId>

                        <artifactId>gson</artifactId>

                        <version>${gson.version}</version>

            </dependency>

POC- Replacing Jackson with Gson in our code:

• Gson FromJson method as replacement for Jackson readValue method-Replaced Jackson methods with Gson methods in saveRoleFunction() method of RoleFunctionListController class as below,

                  Replaced this,

                                  public void saveRoleFunction() {

                                              String data = roleFunc;

                                              RoleFunction availableRoleFunction = mapper.readValue(data, RoleFunction.class);

                                              System.out.println("mapper.readVlaue:"+availableRoleFunction);   

                                   }

              With this,

                                  public void saveRoleFunction() {

                                              String data = roleFunc;

                                              RoleFunction roleFunctonAvailable = gson.fromJson(data, RoleFunction.class);

                                              System.out.println("gson:fromJson:"+roleFunctonAvailable);    

                                  }

               Output for both methods, gson.fromJson() and mapper.readValue, is same.

• Gson toJson method as replacement for Jackson writeValueAsString method-Replaced Jackson methods with Gson methods in buildJsonResponse() method of JsonMessage class as below,

              Replaced this,

                              public static String buildJsonResponse(boolean success, String msg) {

                                           String json = null;

                                           json = new ObjectMapper().writeValueAsString(response);

                                          System.out.println("mapper.WriteValueAsString:"+json);

                                           return json;

                            }

             With this,

                           public static String buildJsonResponse(boolean success, String msg) {

                                        String jsonFromGson = null;

                                         jsonFromGson = new Gson().toJson(response);

                                         System.out.println("Gson().toJson:"+jsonFromGson);

                                         return jsonFromGson;

                          }

            Output for both methods, gson.fromJson() and mapper.readValue, is same

Replacing spring Boot Jackson dependencies with Gson:

         https://www.callicoder.com/configuring-spring-boot-to-use-gson-instead-of-jackson/

Jackson Methods used in our code and their equivalents in Gson:

            Below are few of the methods and their usages in Gson that can be used as replacements for Jackson,