v2ex-QA

gistfile1.java

import java.util.ArrayList;
import java.util.function.Predicate;

public class User {

    private String name;
    private String email;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}


class Main {

    public User filterUserByAttr(ArrayList<User> user, Predicate<User> filterFunc) {
        return user.stream()
                .filter(filterFunc)
                .findFirst()
                .orElse(null);
    }

    public void test() {
        ArrayList<User> userList = new ArrayList<>();
        filterUserByAttr(userList, usr -> "a@b.com".equals(usr.getEmail()));
        filterUserByAttr(userList, usr -> "tom".equals(usr.getName()));

    }
}