guava-concurrent-slides.pdf

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1、com.google.common.util.concurrentTheGuavaTeamcom.google.common.collectcom.google.common.util.concurrentjava.util.concurrentEffectiveJava(concurrencyisinchapter10)JavaConcurrencyinPracticethelinkeddocsandbooksalsohaveadviceaboutJavaconcurrency(generalprinciples,java.util.concurrent)note:s

2、omeslidesrefertomethodsthathavenotyetbeenreleased(listeningDecorator,Futures.allAsList/successfulAsList).WeexpecttoreleasetheseinGuava10inJulycollectImmutable*ConcurrentHashMultisetMultimaps.synchronizedMultimapMapMakerbeforegettingtoutil.concurrent,touchonourotherpackageswekeepconcurren

3、cyinmindinourotherpackagescollect:Immutable*wheneverpossible,forvariousreasonsusethem.linkeddochasadvantagesaswellassometradeoffsoneofmanyreasontousethem:threadsafetyimmutableinthethread-safesensemanyotherclasseswithout"Immutable"inthenameareimmutable(unlikeJDKSimpleDateFormat):CharMatch

4、er,Splittercollect:ConcurrentHashMultisetMultiset≈Mapwithextramethodsandoptionalthread-safetyMapmap=newHashMap();for(StatsProtoproto:protos){Stringhost=proto.getHost();if(!map.containsKey(host)){map.put(host,1);}else{map.put(host,map.get(host)+1);}}codecount

5、snumberoftimeseachhostappearsinaprotomapfromelementtypetonumberofoccurrencescollect:ConcurrentHashMultisetMultiset≈Mapwithextramethodsandoptionalthread-safetyMultisetmultiset=HashMultiset.create();for(StatsProtoproto:protos){multiset.add(proto.getHost());}NumericMap

6、(someday)preferimmutablee.g.,countnumberofqueriestoeachshardNumericMaptosupportlong,doublefor,e.g.,totalnanosecondsspentinanoperationsometimesneedmodifiability,e.g.,stats(probablyfromdifferentthreads,thereforeconcurrency)collect:Multimaps.synchronizedMultimapMultimap≈Map

7、n>withextramethodsandoptionalthread-safetyMap>map=newHashMap();for(StatsProtoproto:protos){Stringhost=proto.getHost();if(!map.containsKey(host)){map.put(host,newArrayList());}map.get(host).add(proto);}codeindexesprotosbyhostcollect:M