The addJson method that needs to be added to the Company class is as follows:

@Override
public void addJson(JsonObjectBuilder builder) {
  builder.add("idCompany", idCompany)
     .add("companyName", companyName);
}

The JsonObject representation of the Company instance is created by calling the builder.build() method in the superclass. The generated JsonObject can then be written by a JsonWriter instance to an output source.

The addJson method that needs to be added to the Project class is as follows:

@Override
public void addJson(JsonObjectBuilder builder) {

  builder.add("idProject", idProject)
     .add("projectName", projectName);

  if(company != null){
     company.addJson(builder);
  }
}   

Note that it is always a good practice to perform null object tests before accessing the object methods. It is possible to create a project object without a company instance and hence we perform the company != null test prior to adding the company JSON properties to the project builder instance. We could have used the following code to add the company properties to the project builder instance directly:

builder.add("idProject", idProject)
     .add("projectName", projectName)
.add("idCompany", company.getIdCompany() )
     .add("companyName", company.getCompanyName() );

However, we would now have replicated the builder.add("idCompany"…) code across two classes (Company.addJson and Project.addJson), thus making the future maintenance prone to errors. Changing the JSON property name from idCompany to companyId, for example, would require the scanning of code to check for possible usage across all classes, not just the Company class. The creation of Company JSON should belong with the Company class as we have implemented.

This Task class will implement the addJson method as follows:

@Override
public void addJson(JsonObjectBuilder builder) {

  builder .add("idTask", idTask)
     .add("taskName", taskName);

  if(project != null){
     project.addJson(builder);

     Company company = project.getCompany();
     company.addJson(builder);
  }        
}

Note once again how we chain the call to addJson for both the project and company classes to add their JSON properties to the task's builder instance.

The User.addJson method is defined as follows:

@Override
public void addJson(JsonObjectBuilder builder) {

  builder.add("username", username)
      .add("firstName", firstName)
      .add("lastName", lastName)
      .add("email", email)
      .add("adminRole", adminRole + "")
      .add("fullName", firstName + " " + lastName);
}

The fullName property is for convenience only; we can just as easily create a fullName field that concatenates the firstName and lastName fields in our Ext JS code. However, keeping this code at the source of the JSON generation allows for easier maintenance. Consider the business change request "add a middleName field to the User entity". The fullName inclusion of the new middleName field is then a trivial exercise and would be available to the Ext JS client without any further changes.

The addJson method adds all of the TaskLog fields to the builder instance. The DATE_FORMAT_yyyyMMdd constant is used to format the taskLogDate to an 8-digit representation of the year/month/day and is added to the TaskLog class as follows:

static final SimpleDateFormat DATE_FORMAT_yyyyMMdd = new SimpleDateFormat("yyyyMMdd");

The addJson method will use the SimpleDateFormat instance to format the taskLogDate field:

public void addJson(JsonObjectBuilder builder) {

  builder.add("idTaskLog", idTaskLog)
    .add("taskDescription", taskDescription)
    .add("taskLogDate", taskLogDate == null ? "" : DATE_FORMAT_yyyyMMdd.format(taskLogDate))
    .add("taskMinutes", taskMinutes);

  if (user != null) {
    user.addJson(builder);
  }
  if (task != null) {
    task.addJson(builder);            
  }
}

The taskLogDate field is being formatted in a way that cannot be misunderstood when converting to a JavaScript Date object in Ext JS clients. Without the use of the SimpleDateFormat instance, the builder instance would call the default toString method on the taskLogDate object to retrieve the String representation, resulting in an output similar to the following:

Wed Aug 14 00:00:00 EST 2013

Using the SimpleDateFormat instance configured with a date pattern of yyyyMMdd will ensure that such a date is formatted to 20130814.