Behavior Design Patterns

Question 1

Name all the behavioral gof patterns

Answer 1

Chain of responsibility
Command
Interpreter
Iterator 
Mediator
Memento
Observer
State
Strategy 
Template Method
Visitor

Question 2

Give an example of the command pattern

Answer 2

Command center with servers in different regions that have many-step tasks. You could have commands for the servers as classes with an Invoker that invokes them. For example, “new RestartCommand(asiaServer)

Question 3

Give an example of the mediator pattern

Answer 3

An angular service. Shares data between different components.

Question 4

Give an example of the chain of responsibility pattern. And how is it diff from / similar to pipeline?

Answer 4

Apigee handling requests. And pipeline has an organizing class

Question 5

Give an example of the observer pattern

Answer 5

Pub/sub - rxjs.

Question 6

Give an example of an interpreter pattern

Answer 6

Rhino.js -> JavaScript that compiles to java

Question 7

Give an example of an iterator pattern

Answer 7

Java iterator. Work with classes that implement iterator. So you can call .hasNext and .next without knowing the inner workings. This is how for : loops work under the hood

Question 8

Give an example of the memento pattern

Answer 8

Something that can save state without breaking encapsulation. So a dB snapshot for example

Question 9

Give an example of a visitor pattern

Answer 9

Something that uses a traverser to walk a structure and perform an operation- for example add new functionality to a bunch of diff classes (my css diffing tool)