How to use Collection remove if his list meet a condition?

Question

I have a list with some Person Object. Here is my Person class:

public class Person(){
// contructors 

private String lastname;

private String firstname;

private List<Place> places;

// getters and setters
}

My Place class is :

public class Place(){
// contructors 

private String town;

// getters and setters
}

I have code to remove some places from person:

List<Person> persons = new ArrayList<Person>();
// adding persons to List
// Below i want to remove person whose place is in town Paris.
persons.removeIf((Person person)-> person.getPlaces(???));

I want to remove a person from the list whose Place meets the following condition place.getTown()=="Paris"

How to write this code?

Answer 1

Add a method hasPlace to Person class:

public boolean hasPlace(String townName) {
    return places.stream()
            .map(Place::getTown)
            .anyMatch(townName::equals);
}

Then, you can use this in the predicate given to the removeIf statement:

persons.removeIf(person -> person.hasPlace("Paris"));

Answer 2

流式播放网上的名单Places ，以确定它是否包含一个Place ，其town是“巴黎”：

persons.removeIf(p-> p.getPlaces().stream().anyMatch(pl->pl.getTown().equals("Paris")));

Answer 3

如果您不想使用removeIf方法，可以使用Filter to

persons.stream().filter(p-> !p.getPlaces().stream().anyMatch(pl->pl.getTown().equals("Paris")));