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![10CONFIDENTIAL
Composed method example
public void add(Object element) {
if (!readOnly) {
int newSize = size + 1;
if (newSize > elements.length) {
Object[] newElements = new Object[elements.length + 10];
for (int index = 0; index < size; index++) {
newElements[index] = elements[index];
elements = newElements;
}
}
elements[size++] = element;
}
}](https://image.slidesharecdn.com/korozsi-201220164317/75/clean-code-uncle-bob-10-2048.jpg)
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clean code - uncle bob
The document discusses principles of clean code and software quality. It summarizes Robert Martin's book "Clean Code" which defines characteristics of clean code such as being focused, readable, and containing only necessary content. It discusses metrics for measuring code quality, such as cyclomatic complexity, and principles for writing clean code, such as following the "Boy Scout Rule" to leave code better than how you found it. Implementation patterns like composed methods are presented, along with advantages of unit testing such as enabling quick changes and understanding design.
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clean code - uncle bob
- 1. 1CONFIDENTIAL Caring About Code Quality TamasKorozsi 2015
- 2.
- 3. 3CONFIDENTIAL Clean Code: AHandbook of Agile Software Craftsmanship by Robert C. Martin The Book
- 4. 4CONFIDENTIAL Does it work? Whatis Clean Code? Does it scale? Is it esthetic? Is it maintainable? Is it testable? Is it short? Is it clever? Does it have explanatory comments? Is it easy to understand? Is it well-structured? Is it object-oriented?
- 5. 5CONFIDENTIAL • Focused • Single-mindedattitude • Undistracted and unpolluted • Readable, simple and direct • Compact and literate • Contains only what is necessary • Makes it easy for other developers to enhance it • Tests should be also clean • Looks like it’s author cares • Contains no duplicates • Foundations are established on tiny abstractions What is Clean Code after all?
- 6. 6CONFIDENTIAL • Subjective • Ifyou can’t measure, you can’t improve • Identify what matters • Defend and justify decisions. The need for measurement
- 7. 7CONFIDENTIAL Cyclomatic complexity public voidfoo() { if (c1) { f1(); } else { f2(); } if (c2) { f3(); } else { f4(); } } • Upper bound for the number of test cases that are necessary to achieve a complete branch coverage • Lower bound for the number of paths through the control flow graph • Desirable value: below 10 Cyclomatic complexity: 3
- 8. 8CONFIDENTIAL Always leave thecampground cleaner than you found it. The Boy Scout Rule
- 9. 9CONFIDENTIAL • Came fromcity crime researchers • A broken window will trigger a building into a smashed and abandoned derelict • So does the software Broken Window Theory
- 10. 10CONFIDENTIAL Composed method example publicvoid add(Object element) { if (!readOnly) { int newSize = size + 1; if (newSize > elements.length) { Object[] newElements = new Object[elements.length + 10]; for (int index = 0; index < size; index++) { newElements[index] = elements[index]; elements = newElements; } } elements[size++] = element; } }
- 11.
- 12. 12CONFIDENTIAL • Divide yourprogram into methods that perform one identifiable task • Keep all of the operation in a method at a same level of abstraction • This will naturally result in programs with many small methods, each few lines long. Composed method pattern by Kent Beck
- 13. 13CONFIDENTIAL Composed method example publicvoid add(Object element) { if (!isReadOnly()) { if (atCapacity()) { grow(); } addElement(element); } }
- 14. 14CONFIDENTIAL • Instant feedback •Allows you to make changes to code quickly • Help you understand the design of the code you are working on • Writing testable code helps to achieve better code quality • Unit tests are a form of sample code • Test-first forces you to plan before you code Advantages of Unit tests
- 15. 15CONFIDENTIAL • Whether theunit you're testing should be isolated from its collaborators • Mockist approach – Isolate from dependencies – More flexible in what you can test • Classic approach – No attempt to isolate unless communicating with the collaborator is awkward – Less brittle tests Unit tests collaborator isolation
- 16. 16CONFIDENTIAL • Change RiskAnalysis and Prediction • Help you identify code that might be particularly difficult to understand, test, or maintain • 𝐶𝑅𝐴𝑃 𝑚 = cycl_comp(m)2 ∗ 1 − 𝑐𝑜𝑣𝑒𝑟𝑎𝑔𝑒 3 + cycl_comp(m) • A method with a CRAP score over 30 is considered unacceptable C.R.A.P. metric Cyclomatic Complexity Coverage required 0 – 5 0% 10 42% 15 57% 20 71% 25 80% 30 100% 31+ Not possible
- 17. 17CONFIDENTIAL • Don’t buildcomplex machines • Don’t build frameworks • Make the software so simple that there are obviously no deficiencies • Keep it simple, stupid (KISS) Rube Goldberg Machines
- 18. 18CONFIDENTIAL • Avoid Cargocult programming • Question authority • Accept feedback and give feedback Angry monkeys experiment
- 19.
- 20. 20CONFIDENTIAL TAMAS_KOROZSI@EPAM.COM THANK YOU FORATTENTION! QUESTIONS?