I finished question 1 but i need help with questoin 2. (and since its a chain questions i just post both )

L.1

A functor is an object that encapsulates a function. Its apply() method takes one parameter,

applies an algorithm and returns a value. It is defined as a 'functional' interface:

interface Functor {

// apply(p) runs some computation on param of type T and returns a value of type R

public R apply(T param);

}

a) Write a class implementing the Functor interface, called LengthFun.

Its apply() function returns the length (Integer) of a String parameter.

Write a LengthFun.main() function that:

o illustrates how the class is used to print the length of a string.

o instantiates a lambda expression of type Functor that does the same

thing as LengthFun.apply(), and uses it to print the length of a string.

b) Define a subclass of LinkedList, called MyList, that has an additional

generic function that "maps" the elements from the list to a new MyList object through a functor object.

The signature of the MyList.map() method is:

public MyList map(Functor fo) {

// write here the code for the map() function.

}

For an object mylist the mylist.map(fo) creates a new MyList object,

iterates over the elements of mylist and appends values fo.apply(current list element)

to the new list. At the end map() returns the new list.

For instance, consider a TimesTwoFun functor whose

Integer apply(Integer param)

function returns 2*param.intValue(). Define a variable tt = new TimesTwoFun();

Now, suppose the elements of a MyList object lst are (-2,1,0,4). Then ,

the new MyList object returned by the lst.map(tt) will have elements (-4,2,0,8).

That is, the lst.map(fo) function creates a new MyList object with elements equal to fo.apply(x),

for each element x from the lst list.

Write the TimesTwoFun class.

Write the MyList class that extends LinkedList, with the only custom method being map()

(all others are inherited from LinkedList).

Write a main() function in MyList.java that:

o implements the example defined above with the TimesTwoFun class.

o repeats the same thing using a lambda expression insted of the TimesTwoFun object.