Chapter 5 – Behavioral Design Patterns

1. The Liskov substitution principle explored in Chapter 1, Getting into Software Design Patterns.
2. The iterator pattern.
3. Yes – the strategy pattern.
4. It is the null object pattern, which provides the type of such a state and limits the causes of null pointer exceptions.
5. This can be the pipeline pattern, the strategy pattern for the map() and filter() methods, or the null object pattern.
6. All clients can be alerted by employing the observer pattern, which also transparently controls conditions.
7. The command pattern can be used. A command is represented by a unique object. An object allows a client to pass parameters and can easily call a callback function.