//: c05:Lunch.java // From Thinking in Java, 2nd Edition // Available at http://www.BruceEckel.com // (c) Bruce Eckel 1999 // Copyright notice in Copyright.txt // Demonstrates class access specifiers. // Make a class effectively private // with private constructors: class Soup { private Soup() {} // (1) Allow creation via static method: public static Soup makeSoup() { return new Soup(); } // (2) Create a static object and // return a reference upon request. // (The "Singleton" pattern): private static Soup ps1 = new Soup(); public static Soup access() { return ps1; } public void f() {} } class Sandwich { // Uses Lunch void f() { new Lunch(); } } // Only one public class allowed per file: public class Lunch { void test() { // Can't do this! Private constructor: //! Soup priv1 = new Soup(); Soup priv2 = Soup.makeSoup(); Sandwich f1 = new Sandwich(); Soup.access().f(); } } ///:~