effective java
•
3 j'aime•478 vues
Geralmente aplicativos buscam resolver uma única tarefa. Mas conforme o passar do tempo, a aplicação tende a ganhar novas features e otimizações, consequentemente ela tende a crescer. Mais features e mais usuários significam mais código. E quanto mais código você escreve, mais código você precisa manter e reescrever. Nos livros "Effective Java" e "Android programming - pushing limits", Joshua Bloch e Erik Hellman, respectivamente, demonstram boas práticas para o desenvolvimento em Java e na plataforma Android. A idéia é fazer um apanhado das melhores práticas trazidas por estes livros. Detalharei o que deve o que não deve ser feito ao aplicar tais práticas.
Recommandé
Contenu connexe
En vedette
En vedette (19)
Similaire à effective java
Similaire à effective java (20)
Plus de tdc-globalcode
Plus de tdc-globalcode (20)
Dernier
Dernier (20)
effective java
- 1. Globalcode – Open4education Trilha – Android Bruno Fernandes Campos Desenvolvedor Mobile EFFECTIVE JAVA
- 5. Globalcode – Open4education Agenda • What the difference in performance between for loops? • How to deal with several parameters classes? • How to make static classes safe? • How to avoid the unecessary objects creation? • Inside classes • Inside for loops • When concatenating strings
- 6. Globalcode – Open4education Comparing For Loops
- 7. Globalcode – Open4education For Loops In Arrays Manual for-loop x Enhanced for-loop
- 8. Globalcode – Open4education For Loops In Arrays Manual for-loop x Enhanced for-loop SAME PERFORMANCE WHEN READING ENTRANCES
- 9. Globalcode – Open4education For loops in Collections For each X Iterator
- 10. Globalcode – Open4education For loops in Collections For each X Iterator SAME PERFORMANCE
- 11. Globalcode – Open4education For loops in ArrayLists Manual for-loop X For each
- 12. Globalcode – Open4education For loops in ArrayLists X For eachManual for-loop
- 13. Globalcode – Open4education For loops in ArrayLists X 1061 ms 1183 ms For each 100000 strings logged in the console performance test Manual for-loop
- 14. Globalcode – Open4education Many Constructors Parameters What should I do?
- 15. Globalcode – Open4education Nutrition Facts Class
- 16. Globalcode – Open4education Telescoping Pattern
- 17. Globalcode – Open4education Using Telescoping Constructor Pattern ● Force some unwanted values ● It does not scale well! ● Parameters reversion
- 18. Globalcode – Open4education Javabeans Pattern
- 19. Globalcode – Open4education Javabeans Pattern ● Easy to read ● Precludes the possibility of making a class imutable ● Imutability -> "All of the information contained in each instance is provided when it is created and is fixed for the lifetime of the object"
- 20. Globalcode – Open4education The builder pattern!
- 21. Globalcode – Open4education Using Builder Pattern ● Easy to read and Write ● Safe -> Imutable
- 22. Globalcode – Open4education How to turn static classes safe
- 23. Globalcode – Open4education Static class
- 25. Globalcode – Open4education Wrong usage
- 26. Globalcode – Open4education AndroidAPIUtils avoiding instantiability
- 27. Globalcode – Open4education Avoid Creating Unecessary Objects
- 28. Globalcode – Open4education Prefeer Static Factory Methods Constructors will always create a new instance!
- 29. Globalcode – Open4education INSIDE CLASSES Avoid Creating Unecessary Objects
- 30. Globalcode – Open4education Bad example
- 31. Globalcode – Open4education Use Static initializers
- 32. Globalcode – Open4education Why use static initialisers? ● Calendar, Date and Timezone instances created only once ● Executing 10 milion times : ○ 1st version took 32000ms ○ 2nd version took 130 ms 250 times faster!
- 33. Globalcode – Open4education INSIDE FOR LOOPS Avoid Creating Unecessary Objects
- 34. Globalcode – Open4education Bad practice at for loops
- 35. Globalcode – Open4education Good allocation example
- 36. Globalcode – Open4education WHEN CONCATENATING STRINGS Avoid Creating Unecessary Objects
- 37. Globalcode – Open4education Bad Practice
- 38. Globalcode – Open4education Bad Practice ● Strings are immutable ● Complexity square n
- 39. Globalcode – Open4education Good Practice ● Linear complexity ● 85 times faster than the first one for 8.000 strings.
- 40. Globalcode – Open4education QUESTIONS? This is the END