How to unmarshal / deserialize collections without setters with JSON-B

Question

I like to write my POJOs not to have setters for collections.

public class Parent {
    private List<Child> children;
    public List<Child> getChildren() {
        if (children == null) {
            children = new ArrayList<Child>();
        }
        return children;
    }
}

// use case example
public class ParentDecorator {
    private final Parent parent;
    public ParentDecorator(Parent parent) {
        this.parent = parent;
    }
    public void addAll(List<Child> children) {
        parent.getChildren().addAll(children);
    }
}

JSON-B serialization works fine, but deserialization does not work as there is no setter for children.

Question: how should I fix this?

Did you find any solution, sir? – Jin Kwon Aug 20 '22 at 06:17 — Jin Kwon, Aug 20 '22 at 06:17
Yes. Read the answers in this thread. – Mikko Tuominen Aug 21 '22 at 07:12 — Mikko Tuominen, Aug 21 '22 at 07:12

score 1 · Accepted Answer · answered Mar 13 '19 at 08:51

Adam Bien wrote a good article Private Fields Serialization with JSON-B and JAX-RS 2.1 / Java EE 8 which I thought would fix it. The idea is to implement a custom PropertyVisibilityStrategy for private fields. Unfortunately it didn't work in my situation for some reason.

I made a small change to Adam's code and changed also the methods to be visible. Now my collections are deserialized.

/**
 * JSON-B visibility strategy for deserialization.
 * 
 * Enables JSON binding of private fields without a setter.
 */
public class JsonDeserializationStrategy implements PropertyVisibilityStrategy {

    @Override
    public boolean isVisible(Field field) {
        return true;
    }

    @Override
    public boolean isVisible(Method method) {
        return true;
    }
}

I only use this PropertyVisibilityStrategy for deserialization as the name suggests. Serialization is done with default configuration.

How to unmarshal / deserialize collections without setters with JSON-B

1 Answers1