which kind of design pattern (Factory design pattern or observer design pattern or iterator design pattern ) should we use to write the java code for the following:

there is a flying system and we want to develop a simple game to our passengers. The game works as follows. The program is taking text from the passenger, once the passenger enters text, two other components (Listeners) of the program are informed that the text has been changed. The first Listener will display the text in reverse and the other will display the information about the text that include (number of characters, number of vowels and number of words).