How to remove properties of objects in ArrayList

Question

I have an end point which returns large chunk of data and I want to remove some part of it.

For example:

Class A

public class A{

private String id;
private Date createOn;
private String processed;
}

Class B

public class B extends MongoDBObject{
private String id;
private Date createOn;
private String processed;
}

Controller

@RestController
@RequestMapping("/v1/read")
public class ReadController{

@Autowired
private StatementBundleService bundleService;

@CrossOrigin
@GetMapping(value = "/statementBundles")
public List<A> listStatements() {
   List<A> result = new ArrayList<A>();

   List<B> bundles = bundleService.getAll();

   for(B bundle: bundles) {
       result.add(new A(bundle));
   }

   return result;
}

I am trying to figure out what is the best way return the list of A without the properties "processed" from both class A and class B.

Should I only use for each loop or iterator? Also should I set properties to null or some other approach?

Answer 1

I doubt if it is possible to alter the property without iterating it. Though you can try java8 for fast and simple output. Have a look in the soln.

public class Java8 {
public static void main(String[] args) {
    List<Student> myList = new ArrayList<Student>();
    myList.add(new Student(1, "John", "John is a good Student"));
    myList.add(new Student(1, "Paul", "Paul is a good Player"));
    myList.add(new Student(1, "Tom", "Paul is a good Teacher"));

    System.out.println(myList);//old list
    myList = myList.stream().peek(obj -> obj.setBiography(null)).collect(Collectors.toList());
    System.out.println(myList);//new list
}

/*Output*/
//[Student [id=1, Name=John, biography=John is a good Student], Student [id=1, Name=Paul, biography=Paul is a good Player], Student [id=1, Name=Tom, biography=Paul is a good Teacher]]
//[Student [id=1, Name=John, biography=null], Student [id=1, Name=Paul, biography=null], Student [id=1, Name=Tom, biography=null]]

}

where Student class as is

public class Student{
private int id;
private String Name;
private String biography;

public Student(int id, String name, String biography) {
    super();
    this.id = id;
    Name = name;
    this.biography = biography;
}
public int getId() {
    return id;
}       
public String getBiography() {
    return biography;
}
public void setBiography(String biography) {
    this.biography = biography;
}
@Override
public String toString() {
    return "Student [id=" + id + ", Name=" + Name + ", biography=" + biography + "]";
}       
}