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java-ja 及1指 チキチキ〆( bェb)?;'.、ゴフッ〇 - Strategy

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脅圷ダイスケ Miyamoto
脅圷ダイスケ Miyamoto

This document discusses the strategy design pattern. It explains that the strategy pattern allows an algorithm to be selected at runtime based on context. It provides examples of using strategies to sort files differently based on a parameter, and to implement different versions of FizzBuzz using the same client code. The strategy interface and classes demonstrate deferring an algorithm implementation to child classes.

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( ) ;'. Strategy @daisuke_m 2011/04/25
? @daisuke_m ? @j5ik2o ? ? Java ? Jiemamy ? Apache Mahout
Strategy ? ? ? ? ( ) ★
? ´
http://ja.wikipedia.org/ wiki/Strategy_
" " ? java.io.File
" " ? java.io.File
" " ? java.io.File
" " ? java.io.File
" " ? java.io.File
File ?´ ? ´ ? ? ´ ? file1, file2, file10 ´
Strategy ? case1 : ? ? case2 : if elseif elseif´ ?
/* case1 */ void sort(List<File> target) { // sort by name } /* case2 */ void sort(List<File> target, String type) { if ("name".equasls(type)) { // sort by name } else if ("size".equals(type)) { // sort by size } else { // default ... } }
Strategy ? case 3 : ( ) ? ? case 4 : ?
java-ja 及1指 チキチキ〆( bェb)?;'.、ゴフッ〇 - Strategy
java-ja 及1指 チキチキ〆( bェb)?;'.、ゴフッ〇 - Strategy
java-ja 及1指 チキチキ〆( bェb)?;'.、ゴフッ〇 - Strategy
java-ja 及1指 チキチキ〆( bェb)?;'.、ゴフッ〇 - Strategy
java-ja 及1指 チキチキ〆( bェb)?;'.、ゴフッ〇 - Strategy
?" "
Strategy ? ? ? ? ? ★ ? SQL ★ RDBMS ?
public interface Strategy { String process(int i); } public class Client { Strategy strategy; public Client(Strategy strategy) { this.strategy = strategy; } public void run() { for (int i = 1; i <= 100; i++) { System.out.println(strategy.process(i); } } }
/* FizzBuzz */ public class FizzBuzzStrategy implements Strategy { public String process(int i) { if (i % 3 == 0 && i % 5 == 0) return "FizzBuzz"; if (i % 3 == 0) return "Fizz"; if (i % 5 == 0) return "Buzz"; return String.valueOf(i); } } /* Nabeatsu */ public class NabeatsuStrategy implements Strategy { public String process(int i) { if (i % 3 == 0 || String.valueOf(i).contains("3")) { return i + " ( ?Д` ) ";; } return String.valueOf(i); } }
Client c = new Client( ); c.run(); new FizzBuzzStrategy() new NabeatsuStrategy() FizzBuzz Nabeatsu 1 1 2 2 Fizz 3 ( ?Д` ) 4 4 Buzz 5 Fizz 6 ( ?Д` ) 7 7 8 8 9 ( ?Д` ) Fizz Buzz 10 11 11 12 ( ?Д` ) Fizz 13 13 ( ?Д` )

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java-ja 及1指 チキチキ〆( bェb)?;'.、ゴフッ〇 - Strategy

  • 1. ( ) ;'. Strategy @daisuke_m 2011/04/25
  • 2. ? @daisuke_m ? @j5ik2o ? ? Java ? Jiemamy ? Apache Mahout
  • 4. ? ´
  • 6. " " ? java.io.File
  • 7. " " ? java.io.File
  • 8. " " ? java.io.File
  • 9. " " ? java.io.File
  • 10. " " ? java.io.File
  • 11. File ?´ ? ´ ? ? ´ ? file1, file2, file10 ´
  • 12. Strategy ? case1 : ? ? case2 : if elseif elseif´ ?
  • 13. /* case1 */ void sort(List<File> target) { // sort by name } /* case2 */ void sort(List<File> target, String type) { if ("name".equasls(type)) { // sort by name } else if ("size".equals(type)) { // sort by size } else { // default ... } }
  • 14. Strategy ? case 3 : ( ) ? ? case 4 : ?
  • 20. ?" "
  • 21. Strategy ? ? ? ? ? ★ ? SQL ★ RDBMS ?
  • 22. public interface Strategy { String process(int i); } public class Client { Strategy strategy; public Client(Strategy strategy) { this.strategy = strategy; } public void run() { for (int i = 1; i <= 100; i++) { System.out.println(strategy.process(i); } } }
  • 23. /* FizzBuzz */ public class FizzBuzzStrategy implements Strategy { public String process(int i) { if (i % 3 == 0 && i % 5 == 0) return "FizzBuzz"; if (i % 3 == 0) return "Fizz"; if (i % 5 == 0) return "Buzz"; return String.valueOf(i); } } /* Nabeatsu */ public class NabeatsuStrategy implements Strategy { public String process(int i) { if (i % 3 == 0 || String.valueOf(i).contains("3")) { return i + " ( ?Д` ) ";; } return String.valueOf(i); } }
  • 24. Client c = new Client( ); c.run(); new FizzBuzzStrategy() new NabeatsuStrategy() FizzBuzz Nabeatsu 1 1 2 2 Fizz 3 ( ?Д` ) 4 4 Buzz 5 Fizz 6 ( ?Д` ) 7 7 8 8 9 ( ?Д` ) Fizz Buzz 10 11 11 12 ( ?Д` ) Fizz 13 13 ( ?Д` )