objects in the cloud - edition 2014
Post on 05-Dec-2014
204 Views
Preview:
DESCRIPTION
How do you write objects for cloud computing? Is Object Oriented Programming still THE way to write apps? What about the state that objects contains?
TRANSCRIPT
- 1. Objects in the Cloud Edizione 2014 Marco Parenzan
- 2. Objective Thinking about #state, #objects and how #cloud need respect using #state and writing #objects
- 3. Musing about some modern #misconceptions
- 4. We cannot take it for granted that The network is reliable Latency is negligible bandwidth is infinite the net is safe the topology doesn't change The transport cost is negligible/zero the network is homogeneous there is only one administrator Mauro Servienti - http://www.communitydays.it/events/2014/vs06/
- 5. Objects in the Cloud Can we apply traditional object oriented principles to the #cloud? Can we think #state as just #objects value?
- 6. Why thinking about #state? #state does not fits so well in the #cloud with: #network #scaling #mainteinance #performances
- 7. What is #state here?
- 8. Understanding #state and #behavior
- 9. What is state? Is a set of attributes (of something) that allows you to identify and characterize it State is something that is maintained in absence of inputs
- 10. State and #software Every software program have a #state That state is what we want for the program In #traditional software development we dont focus on #state, its just there We focus on behavior and how to express it
- 11. What is a behavior? Its something you can do on a state to change it Everything you do is to change yourself (at least!) Many ways to express behavior Imperative Run that behavior on that state! Functional Its a relationship between values Its a relationship between state (of something) in two different times (before and after)
- 12. Why state and behavior are important? Because statet+1=behaviorj(inputt, st) Where t and t+1 are two consecutive instants And there are cases where statet+1=statet
- 13. Where is state? In memory Variables In transient storages (timeout): faster more than infinite Caches Sessions In persistent storage (tinfinite - MTBF) Blobs In structured data Files Databases
- 14. Choose the right representation Choosing the right representation of the state is the most difficult part of an application Relational Database is a choose, not a starting point
- 15. State and the Cloud In the #cloud, the state is the most important thing Define the correct state and how to represent it
- 16. Just objects
- 17. What is an object? It is state and behavior in the same place
- 18. What is an attribute? Is a characteristic (of an object) you can measure (it has a value)
- 19. Some quotes Everything is an object so everything have a state so everything have a behavior If an object have no behavior, is still an object? Or is just state? If an object have no state, but only behavior, is still an object?
- 20. What is modeling? Is the activity of shaping objects
- 21. What is an entity Is something you can model
- 22. You as programmer model entities into objects
- 23. What is OOP (Object Oriented Programming)? Its a way of modeling everything as an object, with state and behavior and classes?
- 24. Objects, non classes We can speak about objects without referring to classes, ever!
- 25. What is a class? A #class is a model for objects A #class is a way to define a model for objects A #class is the typical way to define objects models in a strongly typed (not yet statically typed) language (C#, Java, but also Python and Ruby) There are other ways
- 26. Does a class-based language imply OOP? No, OOP is a way of thinking and modeling at first Class-based languages cannot be an excuse to avoid real principles
- 27. What is a prototype Is an object itself you can use as a model to create others objects copying from it #javascript teaches us that we can write #objects without #classes
- 28. Objects in the Cloud Edizione 2014 Marco Parenzan
top related