How to get a parent based on child fields

Question

Parent class:

public class Person {
    String firstName;
    String lastName;
    Long id;
    List<Phone> phoneNumber = new ArrayList<>();
    int age;

    public Person(String firstName, String lastName, int age, Long id, List<Phone> phone) {
        super();
        this.firstName = firstName;
        this.lastName = lastName;
        this.age = age;
        this.id = id;
        this.phoneNumber = phone;
    }

Child Phone Object (Level 1):

public class Phone {
    String number;
    String type;
    Long id;
    public Phone(String number, String type, Long id) {
        super();
        this.number = number;
        this.type = type;
        this.id = id;
    }
}

I am trying to get a person object whose telephone object type is home, and its number should contain "888".

List<Phone> list = personList.stream().map(p -> p.getPhoneNumber().stream()).
                flatMap(inputStream -> inputStream).filter(p -> p.number.contains("888") && p.type.equals("HOME")).collect(Collectors.toList());

        System.out.println(list.toString());

From the above thread code, I can get the phone object. But how to get the parent of this telephone object in the same function ?.

I tried this way and I get null for disparate objects.

List<Person> finalList = personList.stream().map( per -> {
            List<Phone> phones = per.getPhoneNumber();
            Optional<Phone> ph = phones.stream().filter(p -> p.number.contains("888") && p.type.equals("HOME")).findAny();
        if(ph.isPresent())
            return per;
        return null;
        }).collect(Collectors.toList());

Answer 1

List<Person> result = personList.stream()
    .filter( person -> person.phoneNumber.stream()
                             .anyMatch(phone -> phone.type.equals("HOME") && 
                                                phone.number.contains("888"))
    .collect(Collectors.toList());

What you were looking for are streamphones. This will do the trick.

Having people with their phones, you can now delete phones that do not meet the criteria.

List<Person> result = personList.stream()
        .filter( person -> person.phoneNumber.stream()
                                 .anyMatch(phone -> phone.type.equals("HOME") && 
                                                    phone.number.contains("888"))
        .map(person -> {
            List<Phone> phones = person.phoneNumber.stream()
                                    .filter(phone -> phone.type.equals("HOME") && 
                                                    phone.number.contains("888"))
                                    .collect(Collectors.toList());
            return new Person(person.firstName, person.lastName, person.age, person.id, phones);
        })
        .collect(Collectors.toList());