java8의 새로운 java.util.function.*pojo 반영 방법 이해(코드 포함)

public class City {

    private String name;
    private String code;

    public City() {
    }

    public City(String name, String code) {
        this.name = name;
        this.code = code;
    }

    public String getName() {
        return name;
    }

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

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

}

// Use a constructor with parameters to create a City
City sf = new City("San Francisco", "SF");
// Use a default constructor with no parameters to create a City
City la = new City();
// Set the members using setters
la.setName("Los Angeles");
la.setCode("LA");

// Use the City's method references and assign them to functions
Function<City, String> getNameFunction = City::getName;
Function<City, String> getCodeFunction = City::getCode;

System.out.println("The code for "

        + getNameFunction.apply(sf)
        + " is "
        + getCodeFunction.apply(sf));

-> The code for San Francisco is SF

// Use the City's method references and assign them to biconsumers
BiConsumer<City, String> setNameBiConsumer = City::setName;
BiConsumer<City, String> setCodeBiConsumer = City::setCode;
City ny = new City();
setNameBiConsumer.accept(ny, "New York");
setCodeBiConsumer.accept(ny, "NY");

// Use the City's constructor method reference to create
// a default constructor reference.
Supplier<City> defaultConstructor = City::new;

City sd = defaultConstructor.get();
sd.setName("San Diego");
sd.setCode("SD");

// Use the City's constructor method reference to create
// a two-parameter constructor reference.
BiFunction<String, String, City> twoParameterConstructor = City::new;

City dc = twoParameterConstructor.apply("Washington, D. C.", "DC");