1    package bookExamples.ch19Events.observables; 
2     
3    import java.util.Observable; 
4     
5    public class ObservableBoolean 
6            extends Observable { 
7        private boolean b = false; 
8     
9        public String toString() { 
10           return "b=" + b; 
11       } 
12    
13       public boolean isB() { 
14           return b; 
15       } 
16    
17       public void setB(boolean b) { 
18           if (this.b == b) return; 
19           this.b = b; 
20           setChanged(); 
21       } 
22   } 
23