//: c08:LocalInnerClass.java // Holds a sequence of Objects. // From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002 // www.BruceEckel.com. See copyright notice in CopyRight.txt. import com.bruceeckel.simpletest.*; interface Counter { int next(); } public class LocalInnerClass { private static Test monitor = new Test(); private int count = 0; Counter getCounter(final String name) { // A local inner class: class LocalCounter implements Counter { public LocalCounter() { // Local inner class can have a constructor System.out.println("LocalCounter()"); } public int next() { System.out.print(name); // Access local final return count++; } } return new LocalCounter(); } // The same thing with an anonymous inner class: Counter getCounter2(final String name) { return new Counter() { // Anonymous inner class cannot have a named // constructor, only an instance initializer: { System.out.println("Counter()"); } public int next() { System.out.print(name); // Access local final return count++; } }; } public static void main(String[] args) { LocalInnerClass lic = new LocalInnerClass(); Counter c1 = lic.getCounter("Local inner "), c2 = lic.getCounter2("Anonymous inner "); for(int i = 0; i < 5; i++) System.out.println(c1.next()); for(int i = 0; i < 5; i++) System.out.println(c2.next()); monitor.expect(new String[] { "LocalCounter()", "Counter()", "Local inner 0", "Local inner 1", "Local inner 2", "Local inner 3", "Local inner 4", "Anonymous inner 5", "Anonymous inner 6", "Anonymous inner 7", "Anonymous inner 8", "Anonymous inner 9" }); } } ///:~