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decoy2004 id:decoy2004

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Java Streams API ã‚’ä½¿ã£ã¦ä¾‹å¤–å‡¦ç†ã‚’ãã£ã¡ã‚Šè¡Œãªã†ã‚³ãƒ¼ãƒ‰ã‚’æ›¸ãã“ã¨ã¯é›£ã—ã„ - Qiita
Streams API ã‚’ã“ã‚Œã¾ã§ã¾ã¨ã‚‚ã«ä½¿ã£ãŸã“ã¨ãŒãªã‹ã£ãŸã€‚ ã¾ã¨ã‚‚ã«ä½¿ãŠã†ã¨ã—ãŸã‚‰ä¾‹å¤–å‡¦ç†ã®æ‰±ã„ãŒéžå¸¸ã«é›£ã—ã„ã“ã¨ã‚’å®Ÿæ„Ÿã—ãŸã®ã§ã€ä¸€ä¾‹ã‚’æŒ™ã’ã¦ãã®é›£ã—ã•ã‚’è§£èª¬ã™ã‚‹ã€‚ ã‚„ã‚ŠãŸã„å‡¦ç† è¤‡æ•°ã®ãƒ†ã‚ã‚¹ãƒˆãƒ•ã‚¡ã‚¤ãƒ«ã®ãã‚Œãžã‚Œã‚’1è¡Œãšã¤èªã¿ã“ã¿ã€ç©ºç™½æ–‡å—ã§å„è¡Œã‚’å˜èªžã«åˆ†å‰²ã—ã€å˜èªžã«å¯¾ã—ã¦ä½•ã‹å‡¦ç†ã‚’è¡Œãªã†ã€ã¨ã„ã†ã‚ˆãã‚ã‚‹å‡¦ç†ã‚’å®Ÿè£…ã—ã¦ã¿ã‚ˆã†ã€‚å‡¦ç†ã®æ‰‹é †ã‚’æ‰‹ç¶šãçš„ã«æ›¸ãã¨ä»¥ä¸‹ã®ã‚ˆã†ã«ãªã‚‹ã€‚ ã‚ã‚‹ãƒ‡ã‚£ãƒ¬ã‚¯ãƒˆãƒªã®ç›´ä¸‹ã«å˜åœ¨ã™ã‚‹è¤‡æ•°ã®ãƒ†ã‚ã‚¹ãƒˆãƒ•ã‚¡ã‚¤ãƒ«ï¼ˆæ‹¡å¼µå .txtï¼‰ã‚’1ã¤ãšã¤èªã‚€ å„ãƒ†ã‚ã‚¹ãƒˆãƒ•ã‚¡ã‚¤ãƒ«ã‚’1è¡Œãšã¤èªã‚€ å„è¡Œï¼ˆæ–‡å—åˆ—ï¼‰ã‚’ã€ç©ºç™½æ–‡å—ã‚’åŒºåˆ‡ã‚Šæ–‡å—ã¨ã—ã¦è¤‡æ•°ã®æ–‡å—åˆ—ï¼ˆå˜èªžã¨å‘¼ã¶ã“ã¨ã«ã™ã‚‹ï¼‰ã«åˆ†å‰²ã™ã‚‹ å„å˜èªžã«å¯¾ã—ã¦ä½•ã‹å‡¦ç†ã‚’ã™ã‚‹ã€‚ä»¥ä¸‹ã€å‡¦ç†ã®åå‰ã‚’ analyze ã¨ã™ã‚‹ ã‚¯ãƒ©ã‚¹ã®é››å½¢ ä»¥ä¸‹ã® TextFileProcessor ã‚’æ‹¡å¼µã—ãŸã‚¯ãƒ©ã‚¹ã‚’å®Ÿè£…ã™ã‚‹ã€‚ å„å˜èªžã«é–¢ã™ã‚‹å‡¦ç† analyze ã¯å®Ÿ
decoy2004 2016/05/04
Java

Stream

exception
ãƒªãƒ³ã‚¯
#æ¸‹è°·Java ã«è¡Œã£ã¦ããŸ - mike-neckã®ãƒ–ãƒã‚°
è¡¨é¡Œã®ã¨ãŠã‚Šã§ã™ã€‚ shibuya-java.connpass.com ã§ã€ç™ºè¡¨ã—ã¦ãã¾ã—ãŸã€‚ On stream-lazy-computation from mike_neck Mochida www.slideshare.net å®Ÿéš›ã®ãƒ—ãƒ¬ã‚¼ãƒ³ã®å†…å®¹ã¯ã‚‚ã†å°‘ã—ä¸å¯§ã‹ã¤é›‘ãªè³‡æ–™ã§ã‚„ã‚Šã¾ã—ãŸã€‚ Javaã®Streamã§å¦ã¶é…å»¶å‡¦ç†å®Ÿè£…ãƒ‘ã‚¿ãƒ¼ãƒ³ from mike_neck Mochida www.slideshare.net ã§ã€ç™ºè¡¨è€…ã§æ¬ å¸ã—ãŸäººã‚„æ€ªæˆ‘ã§ã“ã‚Œãªã„äººãŒã„ãŸã®ã§ã€å‹¢ã„ã§ä½œã£ãŸç™ºè¡¨ã‚‚ã—ã¾ã—ãŸã€‚ gradle2.4ã®ãƒ«ãƒ¼ãƒ«ãƒ™ãƒ¼ã‚¹ãƒ¢ãƒ‡ãƒ«ã‚³ãƒ³ãƒ•ã‚£ã‚®ãƒ¥ãƒ¬ãƒ¼ã‚·ãƒ§ãƒ³ from mike_neck Mochida www.slideshare.net ç™ºè¡¨ã®å…ƒãƒã‚¿ã¯ä»¥å‰ã® mike-neck.hatenadiary.com ã¨ mike-neck.hatenadiary.com ã§ã™ã€‚ La
decoy2004 2015/06/09
LazyOptional ãŒå½¹ã«ç«‹ã¤ã®ã¯ã©ã‚“ãªå ´é¢ã ã‚ã†ã€‚

java

stream
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GS Collections ä½¿ã„æ–¹ãƒ¡ãƒ¢ - Qiita
Java Magazine ã§å–ã‚Šä¸Šã’ã‚‰ã‚Œã¦ã„ã¦å˜åœ¨ã¯çŸ¥ã£ã¦ã„ãŸã‚‚ã®ã®ã€ç‰¹ã«ãƒã‚§ãƒƒã‚¯ã¯ã—ã¦ãªã‹ã£ãŸ GS Collectionsã€‚ Java Day Tokyo 2015 ã‚„ JJUG CCC 2015 ã§å†ã³ãã®åå‰ã‚’è€³ã«ã—ã€æ°—ã«ãªã£ã¦ãƒãƒ©ãƒƒã¨å®Ÿè£…ã‚’è¦‹ãŸã¨ã“ã‚ã€é¢ç™½ãã†ã ã£ãŸã®ã§ä½¿ã„æ–¹ã‚’èª¿ã¹ã¦ã¿ãŸã€‚ ã€è¿½è¨˜ã€‘Eclipse Collections 2015 å¹´ã® 10 æœˆã‹ã‚‰ 12 æœˆã«ã‹ã‘ã¦ã€ GS Collections ã¯ Eclipse è²¡å›£ã«ç§»ç®¡ã•ã‚ŒãŸã€‚ åå‰ã‚‚ GS Collections ã‹ã‚‰ Eclipse Collections ã«å¤‰æ›´ã•ã‚ŒãŸã€‚ å…¬å¼ã‚µã‚¤ãƒˆã¯ã“ã¡ã‚‰ â†’ Eclipse Collections - Features you want with the collections you need. (æ—¥æœ¬èªžãƒšãƒ¼ã‚¸) GS Collections ã¨ã€æ©Ÿèƒ½çš„ãªå·®
decoy2004 2015/04/16
java

library

programming

framework

stream
ãƒªãƒ³ã‚¯
Streamã®å¹³å‡ã‚’æ±‚ã‚ã‚‹å‡¦ç†ãŒç²¾åº¦ãŒé«˜ã‹ã£ãŸä»¶(ç·å’Œã‚‚) - ãã¤ãã¨Javaï¼
æ˜¨æ—¥ï¼ŒJavaDayTokyo2015ã§Project Lambdaã®ãƒãƒ³ã‚ºã‚ªãƒ³ã®ãŠæ‰‹ä¼ã„ã‚’ã—ã¦ãã¾ã—ãŸï¼Ž ãã®ä¸ã§ï¼ŒCollectors#averagingDoubleã‚„DoubleStream#averageã®å®Ÿè£…ãŒå„ªç§€ã ã¨ã„ã†ã“ã¨ãŒåˆ†ã‹ã£ãŸã®ã§ï¼Œã¾ã¨ã‚ã¦ãŠãã¾ã™ï¼Ž çµè«–ã‚’å…ˆã«è¨€ã†ã¨StreamAPI*1ãŒå„ªç§€ãªã®ã§ï¼Œãã‚Œã‚’ä½¿ãŠã†ã¨ã„ã†è©±ã§ã™ï¼Ž *2 æ™®é€šã®å®Ÿè£…ã®è©± ã‚ˆãã‚µãƒ³ãƒ—ãƒ«ã§å‡ºã¦ãã‚‹ï¼Œã‚ã‚‹æ•°åˆ—ã‹ã‚‰å¹³å‡å€¤ã‚’æ±‚ã‚ã‚‹å‡¦ç†ã¯ä»¥ä¸‹ã®ã‚ˆã†ã«ãªã£ã¦ã„ã‚‹ã¨æ€ã„ã¾ã™ï¼Ž ã¾ãŸï¼ŒãŠãã‚‰ãæ™®é€šã®ãƒ—ãƒã‚°ãƒ©ãƒžã«å¹³å‡å€¤ã‚’æ±‚ã‚ã‚‹å‡¦ç†ã‚’æ›¸ã‹ã›ã¦ã‚‚åŒæ§˜ãªã‚³ãƒ¼ãƒ‰ã‚’æ›¸ãã¨æ€ã„ã¾ã™ï¼Ž*3 double[] array = {...}; double sum = 0; for (int v : array) { sum += v; } double ave = sum / array.length;å®Ÿã¯ã“ã‚Œã¯ç²¾åº¦ãŒä½Žãï¼Œå®Ÿ
decoy2004 2015/04/12
java

stream
ãƒªãƒ³ã‚¯
Streamã¯AutoCloseableã§ã‚ã‚‹ã¨èªè˜ã—ã¦ã„ãªã„ã¨ã‚¢ãƒ¬ãªä»¶ - mike-neckã®ãƒ–ãƒã‚°
ã“ã‚“ã«ã¡ã‚ã€ã¿ã‘ã§ã™ã€‚ è¡¨é¡Œã€ä½•è¨€ã£ã¦ã‚‹ã‹ã‚ã‹ã‚Šã¾ã›ã‚“ãã€‚ ãƒ•ã‚¡ã‚¤ãƒ«ã‚’èªã¿è¾¼ã‚“ã§Stream<String>ã‚’æ‰±ã†ã¨ãã«ã€ try-with-resourcesã§Stream<String>ã‚’å®£è¨€ã—ã¦ãŠã‹ãªã„ã¨ã€ ãƒªã‚½ãƒ¼ã‚¹ãƒªãƒ¼ã‚¯ãŒã‚ã‚‹ã‹ã‚‚ã—ã‚Œãªã„ã¨ã„ã†ã“ã¨ã§ã™ã€‚ å…·ä½“çš„ã«ã¯ return Files.lines(path, StandardCharsets.UTF_8) .filter(line -> line.startsWith("ERROR") .map(Log Text::new) .collect(Collectors.toList()); ã¨ã‚„ã£ã¦ã„ã‚‹ã¨ã€ãƒ•ã‚¡ã‚¤ãƒ«ã®é–‰ã˜å¿˜ã‚ŒãŒç™ºç”Ÿã™ã‚‹ã®ã§ã€ try(Stream<String> stream = Files.lines(path, StandardCharsets.UTF_8) { return stream.filter(lin
decoy2004 2014/10/13
stream

Java
ãƒªãƒ³ã‚¯
ãƒ¡ãƒ¢ã£ã¨ã‘ Java 8 Lambdas ã€œChapter3ã€œ - A Memorandum
Java 8 Lambdas: Pragmatic Functional Programming (English Edition) ä½œè€…:Richard Warburtonå‡ºç‰ˆç¤¾/ãƒ¡ãƒ¼ã‚«ãƒ¼: O'Reilly Mediaç™ºå£²æ—¥: 2014/03/18ãƒ¡ãƒ‡ã‚£ã‚¢: Kindleç‰ˆ å‰å›ž blog1.mammb.com ã‹ã‚‰ã®ç¶šã Stream Stream ã¯è¤‡é›‘ãªã‚³ãƒ¬ã‚¯ã‚·ãƒ§ãƒ³æ“ä½œã‚’é–¢æ•°åž‹ã‚¢ãƒ—ãƒãƒ¼ãƒã§æ§‹ç¯‰ã™ã‚‹ãƒ„ãƒ¼ãƒ«ã§ã™ã€‚ å¤–éƒ¨ã‚ã‚‹ã„ã¯å†…éƒ¨ã®ç¹°ã‚Šè¿”ã— ãƒãƒ³ãƒ‰ãƒ³å‡ºèº«ã®ã‚¢ãƒ¼ãƒ†ã‚£ã‚¹ã¨ã‚’æ•°ãˆã‚‹æ—§æ¥ã®ã‚³ãƒ¼ãƒ‰ int count = 0; for (Artist artist : allArtists) { if (artist.isFrom("London")) { count++; } } ç¹°ã‚Šè¿”ã—å‡¦ç†ã®æŠ½è±¡ã§ã‚ã‚‹ Iterator ã‚’ä½¿ã£ãŸã‚³ãƒ¼ãƒ‰ int count = 0; Iterator<Ar
decoy2004 2014/09/13
Java8

stream

java
ãƒªãƒ³ã‚¯
Stream APIã§å¤§ããªãƒ•ã‚¡ã‚¤ãƒ«ã‚’èªã¿è¾¼ã‚€ã¨ - torutkã®ãƒ–ãƒã‚°
Java SE 7ã§å°Žå…¥ã•ã‚ŒãŸNIO2ã®Filesã‚¯ãƒ©ã‚¹ã§readAllLinesãƒ¡ã‚½ãƒƒãƒ‰ã‚’ä½¿ã£ã¦å¤§ããªãƒ•ã‚¡ã‚¤ãƒ«ã‚’èªã‚€ã¨ã€ãƒ’ãƒ¼ãƒ—ãƒ¡ãƒ¢ãƒªã‚’åœ§è¿«ã¾ãŸã¯OutOfMemoryErrorã‚’èµ·ã“ã—ã¾ã™ã€‚ List<String> lines = Files.readAllLines(Paths.get(args[0]), StandardCharsets.UTF_8); Windows 7 64bitï¼ˆ12GBãƒ¡ãƒ¢ãƒªï¼‰ã§ã€Java SE 8 64bitç‰ˆä¸Šã§ãƒ’ãƒ¼ãƒ—ãƒ¡ãƒ¢ãƒªã‚µã‚¤ã‚ºã®ã‚ªãƒ—ã‚·ãƒ§ãƒ³ã‚’æŒ‡å®šã›ãšã«ï¼ˆãƒ‡ãƒ•ã‚©ãƒ«ãƒˆï¼‰å®Ÿè¡Œã—ã€8GBã®ãƒ•ã‚¡ã‚¤ãƒ«ã‚’ä¸Šè¿°ã‚³ãƒ¼ãƒ‰ã§èªã¿è¾¼ã¾ã›ãŸã¨ã“ã‚OutOfMemoryErrorãŒç™ºç”Ÿã—ã¾ã—ãŸã€‚ Java SE 8ã§å°Žå…¥ã•ã‚ŒãŸStream APIã‚’ä½¿ã£ã¦å¤§ããªãƒ•ã‚¡ã‚¤ãƒ«ã‚’èªã¿è¾¼ã‚€ã¨ã©ã†ã‹è©¦ã—ã¦ã¿ã¾ã—ãŸã€‚ try (BufferedReader reader = Files.newB
decoy2004 2014/08/26
ã€ŽJava SE 8ã§å°Žå…¥ã•ã‚ŒãŸStream APIã‚’ä½¿ã£ã¦å¤§ããªãƒ•ã‚¡ã‚¤ãƒ«ã‚’èªã¿è¾¼ã‚€ã¨ã©ã†ã‹è©¦ã—ã¦ã¿ã¾ã—ãŸã€‚ã€

Java

api

stream

java8
ãƒªãƒ³ã‚¯
Java8 Streamã§ãƒãƒªãƒãƒªã‚„ã‚Œã‚‹ã‚ˆã†ã«ãªã‚ŠãŸã„äººã®ãŸã‚ã®Functional Interfaceã¾ã¨ã‚ - mike-neckã®ãƒ–ãƒã‚°
ã“ã‚“ã«ã¡ã‚ã€ã¿ã‘ã§ã™ã€‚ ã‚‚ã†ã€Streamã®æ›¸ãã™ãŽã§ã€ ãªã‚“ã ã‹ã€foræ–‡ãŒæ›¸ã‘ãªã„èº«ä½“ã«ãªã£ã¦ã—ã¾ã„ã¾ã—ãŸ(å¤§è¢ˆè£Ÿ) ã¨ã„ã†ã‚ã‘ã§ã€Streamãªã®ã§ã™ãŒã€ æ…£ã‚Œã¦ã„ãªã„ã¨ ã€Œã¯ã‚ˆï¼Supplier<?>ã€BinaryConsumer<?, ?>ã‚’ã¯ã‚ˆï¼ã€ ã¨IDEã«ã›ã‹ã•ã‚Œã¦ã€ ã‚ã‚Œã£ï¼Ÿã“ã‚Œã£ã¦ãªã‚“ã ã£ã‘ï¼Ÿã£ã¦ãªã£ã¦ã—ã¾ã† ã®ã§ã¯ãªã„ã‹ã¨æ€ã„ã¾ã™ã€‚ ã¨ã„ã†ã‚ã‘ã§ã€Streamã§ä½¿ã†ç”¨é€”ã§ Functional Interfaceã‚’ã¾ã¨ã‚ã¦ã¿ã‚‹ã“ã¨ã«ã—ã¾ã—ãŸã€‚ Streamã®ç”Ÿæˆ(source)ã«ç”¨ã„ã‚‹ã‚‚ã® Supplier<T> å¼•æ•°ãªã—ã§ã€ã‚ªãƒ–ã‚¸ã‚§ã‚¯ãƒˆã‚’ç”Ÿæˆã™ã‚‹Functional Interfaceã§ã™ã€‚ Stream#generateãƒ¡ã‚½ãƒƒãƒ‰ã§åˆ©ç”¨ã—ã¾ã™ã€‚ ä¾‹ @Test public void supplier_Tã®ã‚µãƒ³ãƒ—ãƒ« () { final AtomicInteger
decoy2004 2014/08/08
stream

java

ãƒ—ãƒã‚°ãƒ©ãƒŸãƒ³ã‚°
ãƒªãƒ³ã‚¯
Java8 Stream API ã§ã¯ collector ã¨ã‹ã‚’è¤‡æ•°å›žå‘¼ã¶ã¨å®Ÿè¡Œæ™‚ã‚¨ãƒ©ãƒ¼ã«ãªã‚‹ - tokuhirom's blog
ä»¥ä¸‹ã®ã‚ˆã†ãªã‚³ãƒ¼ãƒ‰ã¯ã€å®Ÿè¡Œæ™‚ã‚¨ãƒ©ãƒ¼ã«ãªã‚‹ã€‚ Stream<String> ss = Arrays.asList("hoge", "fuga").stream(); System.out.println(ss.count()); System.out.println(ss.count()); ã‚¹ã‚¿ãƒƒã‚¯ãƒˆãƒ¬ãƒ¼ã‚¹ã¯ä»¥ä¸‹ã®ã‚ˆã†ã«ãªã‚‹ã€‚ stream has already been operated upon or closed java.lang.IllegalStateException at java.util.stream.AbstractPipeline.<init>(AbstractPipeline.java:203) at java.util.stream.LongPipeline.<init>(LongPipeline.java:91) at java.util.stream.Lo
decoy2004 2014/07/12
stream

java

Java8
ãƒªãƒ³ã‚¯
ã€ŒJavaã®é‰±è„ˆã€é€£è¼‰é–‹å§‹ | ã•ã«ã‚ã‚‰ãš
WEB+DB PRESS ã® Vol.81 ã‹ã‚‰ JVM ã‚’ä¸å¿ƒã¨ã—ãŸé€£è¼‰ã‚’å§‹ã‚ã¾ã—ãŸã®ã§æ˜¯éžè²·ã£ã¦ä¸‹ã•ã„ã€‚ 2014/6/24 ç™ºå£²ã§ã™ã€‚æ›¸åº—ã«ã¯æ—¢ã«ä¸¦ã‚“ã§ã„ã‚‹ã‹ã¨æ€ã„ã¾ã™ã€‚ ã“ã‚Œã¯ã‚¢ãƒžã‚¾ãƒ³ã®ã‚¢ãƒ•ã‚£ãƒªã‚¨ã‚¤ãƒˆãƒªãƒ³ã‚¯ã§ã™ã®ã§ã€è¸ã‚“ã ç›´å¾Œã«å†·è”µåº«ç‰ã®å¤§åž‹å®¶é›»ã‚’è³¼å…¥ã—ã¦é ‚ã‘ã‚‹ã¨åƒ•ãŒå–œã³ã¾ã™ã€‚ é›»åæ›¸ç±ç‰ˆã‚‚ã‚ã‚Šã¾ã™ã®ã§ç‰©ç†çš„ãªåª’ä½“ã«èˆˆå‘³ãŒãªã„æ–¹ã¯ PDF ã‚’è²·ã£ã¦ä¸‹ã•ã„ã€‚ WEB+DB PRESS Vol.81@Gihyo Digital Publishingåˆå›žã®å†…å®¹ã¯ãƒ©ãƒ ãƒ€å¼ + RxJava#ä»Šå›žã®å†…å®¹ã¨ã—ã¦ã¯ Java8 ã®ãƒ©ãƒ ãƒ€å¼ã«é–¢ã™ã‚‹ç°¡å˜ãªèª¬æ˜Žã‹ã‚‰ã€ãƒ©ãƒ ãƒ€å¼ã‚’åˆ©ç”¨ã—ã¦RxJavaã‚’ä½¿ã†ã¨ã“ã‚“ãªã«ä¾¿åˆ©ã¨ã„ã†è©±ã‚’æ›¸ãã¾ã—ãŸã€‚ è¨˜äº‹å†…ã§ Stream API ã«é–¢ã—ã¦èª¬æ˜Žã—ãªã‹ã£ãŸæœ€å¤§ã®ç†ç”±ã¯ãƒ©ãƒ ãƒ€å¼ã¨ Stream API ã«é–¢ã™ã‚‹é©åˆ‡ã§å¦¥å½“ãªèª¬æ˜Žã«ã¤ã„ã¦ã¯æ¡œåºã•ã‚“ã®è¨˜äº‹ã‚’èªã‚ã°è‰¯ã„ã¨è€ƒ
decoy2004 2014/06/24
stream

api

java

Java8

RxJava

lambda
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