P9.17

Declare an interface Filter as follows:

public interface Filter { boolean accept(Object x); }

Write a method: public static ArrayList collectAll(ArrayList objects, Filter f) that returns all objects in the objects list that are accepted by the given filter.

Provide a class ShortWordFilter whose filter method accepts all strings of length < 5.

Then write a program that asks the user for input and output textfile names, reads all words from inputfile, puts them into an ArrayList, calls collectAll, and prints a list of the short words to the output file.