File: Main.java
public class Main {
public static void main(String[] a) {
MessageData source = new SimpleMessageData("Hello, world");
MessageReporter destination = new StdoutMessageReporter();
destination.write(source.getMessage());
}
}
interface MessageReporter {
void write(String message);
}
interface MessageData {
String getMessage();
}
class StdoutMessageReporter implements MessageReporter {
public void write(String message) {
System.out.println(message);
}
}
class SimpleMessageData implements MessageData {
private final String message;
public SimpleMessageData() {
this("Hello, world");
}
public SimpleMessageData(String message) {
this.message = message;
}
public String getMessage() {
return this.message;
}
}