Software Design in Practice (with Java examples)
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The document discusses various aspects of software design, including the importance of principles such as abstraction, encapsulation, and modularization. It emphasizes the cost of poor software quality and introduces concepts like refactoring, design smells, and concurrency issues. Additionally, it features practical examples and discussions around coding practices, highlighting the need for better software design to improve maintainability and performance.
![$ cat limerick.txt | tr -cs "[:alpha:]" "n" | awk '{print length(), $0}' | sort | uniq
1 a
2 as
2 of
2 on
3 And
3 Who
3 she
3 the
3 was
4 They
4 With
4 face
4 from
4 lady
4 ride
4 rode
5 Niger
5 There
5 smile
5 tiger
5 young
6 inside
6 smiled
8 returned](https://image.slidesharecdn.com/softwaredesigninpractice-170121132948/85/Software-Design-in-Practice-with-Java-examples-17-320.jpg)
![Refactored Example âŠ
You can use only date,
time, or even timezone,
and combine them as
needed!
LocalDate today = LocalDate.now();
System.out.println(today);
LocalTime now = LocalTime.now();
System.out.println(now);
ZoneId id = ZoneId.of("Asia/Tokyo");
System.out.println(id);
LocalDateTime todayAndNow = LocalDateTime.now();
System.out.println(todayAndNow);
ZonedDateTime todayAndNowInTokyo = ZonedDateTime.now(ZoneId.of("Asia/Tokyo"));
System.out.println(todayAndNowInTokyo);
2016-03-17
13:28:06.927
Asia/Tokyo
2016-03-17T13:28:06.928
2016-03-17T16:58:06.929+09:00[Asia/Tokyo]](https://image.slidesharecdn.com/softwaredesigninpractice-170121132948/85/Software-Design-in-Practice-with-Java-examples-44-320.jpg)
![Whatâs that smell?
switch'(transferType)'{'
case'DataBuïŹer.TYPE_BYTE:'
byte'bdata[]'='(byte[])inData;'
pixel'='bdata[0]'&'0xïŹ;'
length'='bdata.length;'
break;'
case'DataBuïŹer.TYPE_USHORT:'
short'sdata[]'='(short[])inData;'
pixel'='sdata[0]'&'0xïŹïŹ;'
length'='sdata.length;'
break;'
case'DataBuïŹer.TYPE_INT:'
int'idata[]'='(int[])inData;'
pixel'='idata[0];'
length'='idata.length;'
break;'
default:'
throw' new' UnsupportedOperaQonExcepQon("This' method' has' not' been' "+' "implemented'
for'transferType'"'+'transferType);'
}'](https://image.slidesharecdn.com/softwaredesigninpractice-170121132948/85/Software-Design-in-Practice-with-Java-examples-49-320.jpg)
inData;(
pixel(=(bdata[0](&(0xïŹ;(
length(=(bdata.length;(
break;(
case(DataBuïŹer.TYPE_USHORT:(
short(sdata[](=((short[])inData;(
pixel(=(sdata[0](&(0xïŹïŹ;(
length(=(sdata.length;(
break;(
case(DataBuïŹer.TYPE_INT:(
int(idata[](=((int[])inData;(
pixel(=(idata[0];(
length(=(idata.length;(
break;(
default:(
throw( new( UnsupportedOperaRonExcepRon("This( method(
has( not( been( "+( "implemented( for( transferType( "( +(
transferType);(
}!](https://image.slidesharecdn.com/softwaredesigninpractice-170121132948/85/Software-Design-in-Practice-with-Java-examples-50-320.jpg)
![Language Features & Refactoring
public static void main(String []file) throws Exception {
// process each file passed as argument
// try opening the file with FileReader
try (FileReader inputFile = new FileReader(file[0])) {
int ch = 0;
while( (ch = inputFile.read()) != -1) {
// ch is of type int - convert it back to char
System.out.print( (char)ch );
}
}
// try-with-resources will automatically release FileReader object
}
public static void main(String []file) throws Exception {
Files.lines(Paths.get(file[0])).forEach(System.out::println);
}
Java 8 lambdas and streams](https://image.slidesharecdn.com/softwaredesigninpractice-170121132948/85/Software-Design-in-Practice-with-Java-examples-53-320.jpg)
Software Design in Practice (with Java examples)
- 1. Software Design in Practice Ganesh Samarthyam Entrepreneur; author; speaker [email protected] www.codeops.tech
- 2. Discussion Question Which one of the following is MOST IGNORED aspect in software development? â Code quality â Software testing â Software design â Programming
- 5. "... a delightful, engaging, actionable read... you have in your hand a veritable ïŹeld guide of smells... one of the more interesting and complex expositions of software smells you will ever ïŹnd..." - From the foreword by Grady Booch (IBM Fellow and Chief Scientist for Software Engineering, IBM Research)
- 6. Why Care About Principles?
- 7. Poor software quality costs more than $150 billion per year in U.S. and greater than $500 billion per year worldwide - Capers Jones
- 8. Source: Estimating the Principal of an Application's Technical Debt, Bill Curtis, Jay Sappidi, Alexandra Szynkarski, IEEE Software, Nov.-Dec. 2012.
- 9. Source: Consortium of IT Software Quality (CISQ), Bill Curtis, Architecturally Complex Defects, 2012
- 10. âCraig Larman "The critical design tool for software development is a mind well educated in design principles"
- 11. For Architects: Design is the Key!
- 12. Design Thinking
- 13. Fundamental Principles in Software Design Principles* Abstrac/on* Encapsula/on* Modulariza/on* Hierarchy*
- 14. Proactive Application: Enabling Techniques
- 16. $ cat limerick.txt There was a young lady of Niger Who smiled as she rode on a tiger. They returned from the ride With the lady inside And a smile on the face of the tiger.
- 17. $ cat limerick.txt | tr -cs "[:alpha:]" "n" | awk '{print length(), $0}' | sort | uniq 1 a 2 as 2 of 2 on 3 And 3 Who 3 she 3 the 3 was 4 They 4 With 4 face 4 from 4 lady 4 ride 4 rode 5 Niger 5 There 5 smile 5 tiger 5 young 6 inside 6 smiled 8 returned
- 18. List<String> lines = Files.readAllLines(Paths.get("./limerick.txt"), Charset.defaultCharset()); Map<Integer, List<String>> wordGroups = lines.stream() .map(line -> line.replaceAll("W", "n").split("n")) .flatMap(Arrays::stream) .sorted() .distinct() .collect(Collectors.groupingBy(String::length)); wordGroups.forEach( (count, words) -> { words.forEach(word -> System.out.printf("%d %s %n", count, word)); }); 1 a 2 as 2 of 2 on 3 And 3 Who 3 she 3 the 3 was 4 They 4 With 4 face 4 from 4 lady 4 ride 4 rode 5 Niger 5 There 5 smile 5 tiger 5 young 6 inside 6 smiled 8 returned
- 19. Parallel Streams
- 20. race conditions
- 22. deadlocks
- 24. I really really hate concurrency problems
- 26. long numOfPrimes = LongStream.rangeClosed(2, 100_000) .ïŹlter(PrimeNumbers::isPrime) .count(); System.out.println(numOfPrimes); Prints 9592 2.510 seconds
- 27. Parallel code Serial code Letâs ïŹip the switch by calling parallel() function
- 28. long numOfPrimes = LongStream.rangeClosed(2, 100_000) .parallel() .ïŹlter(PrimeNumbers::isPrime) .count(); System.out.println(numOfPrimes); Prints 9592 1.235 seconds
- 29. Wow! Thatâs an awesome ïŹip switch!
- 30. Internally, parallel streams make use of fork-join framework
- 31. Discussion Question What is refactoring? â Needless rework! â Changing internal structure without changing external behaviour â Changing external quality (scalability, performance, etc) â Fixing hidden or latent defects
- 33. Refactoring
- 38. Discussion Example // using java.util.Date Date today = new Date(); System.out.println(today); $ java DateUse Wed Dec 02 17:17:08 IST 2015 Why should we get the time and timezone details if I only want a date? Can I get rid of these parts? No!
- 39. So What! Date today = new Date(); System.out.println(today); Date todayAgain = new Date(); System.out.println(todayAgain); System.out.println(today.compareTo(todayAgain) == 0); Thu Mar 17 13:21:55 IST 2016 Thu Mar 17 13:21:55 IST 2016 false What is going on here?
- 40. Refactoring for Date Replace inheritance with delegation
- 41. Joda API JSR 310: Java Date and Time API Stephen Colebourne
- 43. Refactored Solution LocalDate today = LocalDate.now(); System.out.println(today); LocalDate todayAgain = LocalDate.now(); System.out.println(todayAgain); System.out.println(today.compareTo(todayAgain) == 0); 2016-03-17 2016-03-17 true Works ïŹne now!
- 44. Refactored Example ⊠You can use only date, time, or even timezone, and combine them as needed! LocalDate today = LocalDate.now(); System.out.println(today); LocalTime now = LocalTime.now(); System.out.println(now); ZoneId id = ZoneId.of("Asia/Tokyo"); System.out.println(id); LocalDateTime todayAndNow = LocalDateTime.now(); System.out.println(todayAndNow); ZonedDateTime todayAndNowInTokyo = ZonedDateTime.now(ZoneId.of("Asia/Tokyo")); System.out.println(todayAndNowInTokyo); 2016-03-17 13:28:06.927 Asia/Tokyo 2016-03-17T13:28:06.928 2016-03-17T16:58:06.929+09:00[Asia/Tokyo]
- 45. More classes in Date/Time API
- 47. Liskovâs Substitution Principle (LSP) It#should#be#possible#to#replace# objects#of#supertype#with# objects#of#subtypes#without# altering#the#desired#behavior#of# the#program# Barbara#Liskov#
- 49. Whatâs that smell? switch'(transferType)'{' case'DataBuïŹer.TYPE_BYTE:' byte'bdata[]'='(byte[])inData;' pixel'='bdata[0]'&'0xïŹ;' length'='bdata.length;' break;' case'DataBuïŹer.TYPE_USHORT:' short'sdata[]'='(short[])inData;' pixel'='sdata[0]'&'0xïŹïŹ;' length'='sdata.length;' break;' case'DataBuïŹer.TYPE_INT:' int'idata[]'='(int[])inData;' pixel'='idata[0];' length'='idata.length;' break;' default:' throw' new' UnsupportedOperaQonExcepQon("This' method' has' not' been' "+' "implemented' for'transferType'"'+'transferType);' }'
- 50. Replace conditional with polymorphism protected(int(transferType;! protected(DataBuïŹer(dataBuïŹer;! pixel(=(dataBuïŹer.getPixel();( length(=(dataBuïŹer.getSize();! switch((transferType)({( case(DataBuïŹer.TYPE_BYTE:( byte(bdata[](=((byte[])inData;( pixel(=(bdata[0](&(0xïŹ;( length(=(bdata.length;( break;( case(DataBuïŹer.TYPE_USHORT:( short(sdata[](=((short[])inData;( pixel(=(sdata[0](&(0xïŹïŹ;( length(=(sdata.length;( break;( case(DataBuïŹer.TYPE_INT:( int(idata[](=((int[])inData;( pixel(=(idata[0];( length(=(idata.length;( break;( default:( throw( new( UnsupportedOperaRonExcepRon("This( method( has( not( been( "+( "implemented( for( transferType( "( +( transferType);( }!
- 51. Discussion Question What is the biggest deterrent to performing refactoring? â Deadlines! (Lack of time and resources) â Fear of breaking the working code â Not able to get management buy-in for refactoring â Lack of technical skills to perform refactoring
- 53. Language Features & Refactoring public static void main(String []file) throws Exception { // process each file passed as argument // try opening the file with FileReader try (FileReader inputFile = new FileReader(file[0])) { int ch = 0; while( (ch = inputFile.read()) != -1) { // ch is of type int - convert it back to char System.out.print( (char)ch ); } } // try-with-resources will automatically release FileReader object } public static void main(String []file) throws Exception { Files.lines(Paths.get(file[0])).forEach(System.out::println); } Java 8 lambdas and streams
- 54. Tangles in JDK
- 55. Copyright © 2015, Oracle and/or its afïŹliates. All rights reserved
- 56. Copyright © 2015, Oracle and/or its afïŹliates. All rights reserved
- 57. Structural Analysis for Java (stan4j)
- 58. JArchitect
- 59. InFusion
- 60. SotoArc
- 61. CodeCity
- 63. BANGALORE CONTAINER CONFERENCE 2017 Sponsorship Deck Apr 07 Bangalore www.containerconf.in
- 64. [email protected] @GSamarthyam www.codeops.tech slideshare.net/sgganesh +91 98801 64463 bit.ly/ganeshsg