How to merge two complex objects in java

Question

I have two java objects and I want to merge them into single object. Problem is the two objects does not contain plain primitive type properties(fields) they contain complex

Answer 1

import java.util.Objects;
import java.util.function.Consumer;
import java.util.function.Supplier;

public final class PropertyMerger {

    public static  void mergeProperty(
            Supplier sourceGetter,
            Supplier targetGetter,
            Consumer targetSetter
    ) {
        var source = sourceGetter.get();
        var target = targetGetter.get();

        if (!Objects.equals(source, target)) {
            targetSetter.accept(source);
        }
    }

}

Somwhere in your code:

PropertyMerger.mergeProperty(facebookOAuth2User::getId, existingFacebookOAuth2UserDB::getFacebookId, existingFacebookOAuth2UserDB::setFacebookId);
PropertyMerger.mergeProperty(facebookOAuth2User::getName, existingFacebookOAuth2UserDB::getName, existingFacebookOAuth2UserDB::setName);