八年级英语上册&Unit&7&Will&people&have&robots测试卷（A卷）（新版）人教新目标版&&新目标
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Unit7Willpeoplehaverobots测试卷（A卷）Class______________Name______________一、单词拼写，每空一词1.Hewantstobea__________(科学家)whenhegrowsup.2.Hehas_________(已经)seenthefilm.3.Youwillget_________(乏味的)ifyoudothesamejobagainandagain.4.Ibelieverobotswilldoalotofhardworkthat__________(人类)wouldn’tliketodo.5.It_________(似乎)thateveryonelovestolaugh.6.Shewillbeana__________likeYangLiweiinfiveyears.7.R__________cantakeustothemoon.8.Maybepeoplewilltravelthroughs__________(太空)tothemooninthefuture.9.Peoplewillbea__________tovisitMarsinthefuture.10.It’si__________forhimtocookdinner,becauseheissoyoung.二、用所给词的适当形式填空1.There(be)manypeopleattomorrow’sparty.2.Weall(take)partinthesportsmeetinglastweek.3.Listen,who(sing)inEnglish?4.Hefifteenyearsoldnextweek.5.-they(buy)thehouse?CYes,theywill.6.WearesureHongKongwillbeeven(good)tomorrow.7.Therewillbe(few)treesinthefuture.8.Peoplewilllive(be)200yearsold.9.Therewillbe(many)peoplein30years.10.Thechildrenwillusecomputers(study)athome.三、用方框中所给词的适当形式填空littlealittlefewafewmanymuch1.Hurryup!Thereis__________timeleft.2.CDoyouknowEnglish?CYes,butonly__________.3.ThisEnglisharticleisveryeasyforustoread.Thereare__________newwordsinit.4.We’llhave__________freetimeiftheteachergivesus_______homework.5.Wedon’thave__________milktodrink.Ihavetogetsome.6.Thereare__________peopleintheparkatweekendsthanonweekdays.7.__________and_________peoplehavetheirowncomputerstoday.8.Therearetoo__________peopleonthebus.9.NextyearJim’sgoingtoretire,sohewillhave__________freetimetorelax.四、单项选择()1.CWhenwillyoufinishbuildingtheapartment?C______twoyears.A.OnB.InC.AtD.Of()2.CTheproblemis______forme.Icanworkitoutinfiveminutes.CYouaresosmart.A.hardB.simpleC.necessaryD.good()3.CHowwasyourvacationinCanada?CItcouldn’tbeworse!Idon’t______wanttotalkaboutit!A.evenB.neverC.overD.then()4.CNothing______impossibleinthisworld.CYes.Anythingcanhappen.A.makesB.thinksC.seemsD.feels()5.CThere______abasketballmatchinourschoolWouldyouliketocomeandwatchitwithme?CYes,I’dloveto.A.willbeB.wasC.isgoingtohaveD.has()6.CMysonwasable______threelanguageswhenhewasfifteenyearsold.CHewassogreat.A.speakingB.spokeC.speakD.tospeak()7.CPeoplecangotoMarsonvacationinfiftyyears.C______.Thereisnoairthere.A.SoundsinterestingB.That’srightC.That’sagoodideaD.Idisagree()8.Mylifealotthanitisnow.A.willbe,goodB.is,betterC.willbe,goodD.willbe,better()9.Itwilltakeyearstomakerobotsthemostunpleasantthings.A.hundred,doB.hundredsof,todoC.twohundreds,doD.hundredsof,do()10.Heonlysaiditfor,hedidn’treallymeanit.A.joyB.funC.jokeD.thank()11. You ______ better if you ______ harder. A. learn, work B. are learning, are working C. will learn, work D. learn, will work()12.Therewillbe_________pollutionthisyearthanlastyear.A.fewer B.much C.less D.many()13.―Willpeoplelivetobe300yearsold?―_________.A.No,theyaren't B.No,theywon't C.No,theydon't D.No,theycan't()14.Ithinkpeopleherearefriendly.Doyouagree_________me?A.with B.to C.on D.from()15.CWhereisMissWang?―ShewenttoHainanIslandlastweekandwillcomeback_________sixdays.A.ago B.later C.behind D.in()16.C_________willtheyplay?CTheywillplayfootball.A.Whatsubject B.Whatsport C.Whatfood D.Whatlanguage()17.Iwillseeyouagain_________.A.aday B.everyday C.oneday D.everyday()18.Ihopeyourdreamwill_________.A.eon()19.Everyonewantsto_________tothemoonforvacations.A.walk B.run C.swim D.fly()20.―Howmanybirdscanyouseeinthetrees?―Icansee_________birdsinthem.A.hundredsof B.fivehundreds C.hundredof D.fivehundredsof()21.______willtheweather_________liketomorrow?A.What,/B.What,beC.How,beD.How,/()22.______thefuturecanbedifficult.A.PredictingB.PredictC.PredictsD.Predicted()23.WearenotsureifWangHaicould______ZhangJuninthematch.A.beatB.winC.hitD.fail()24.peoplerobotsintheirhomein100years?A.Will,haveB.Do,haveC.Did,haveD.Have,have()25.-Doyoulikethecitylifeorthecountrylife?-It'shardtosay.Inthecitythereis_____fun,butinthecountrythereis_____pollution.A.moreB.lessC.fewerD.much()26.-WilltherebepeopleinChinaintenyears?-No,therewon’tA.fewerB.muchC.lessD.many()27.Ifthereare_____trees,theairinourcitywillbe_____cleaner.A.moreB.moreC.muchD.more()28.Ipredicthewillbeanengineer_____tenyears.A.inB.afterC.laterD.for五、阅读理解(A)WhentheAmericansweregettingreadytosendtheirfirstmentothemoon,anoldAustralianwaswatchingTVinarestaurant.TherewasanEnglishmanintherestaurant,too,andhesaidtotheAustralian,“TheAmericansareclever,aren’tthey?Theyaregoingtosendsomementothemoon.Itisaverylongwayfromourworld.”“Oh,that’snothing,”theAustralianansweredquickly.“Ourcountryisgoingtosendsomepeopletothesuninafewmonths.That’smuchfartherawaythanthemoon,youknow.”“Oh,yes,itis,“theEnglishmansaid,“butthesunistoohotforpeopletogoto.”TheAustralianlaughedandsaid,“Wewon’tgotothesunintheday,ofcourse.We’llgothereatnight.”()1.Whoweregoingtosendtheirfirstmentothemoon?TheAmericansB.TheAustraliansC.TheEnglishmen()2.WhereweretheAustralianandEnglishmanwatchingTV?InthecinemaB.OutsideashopC.Inarestaurant()3.TheEnglishmanthoughtwereclever.A.theAmericansB.theAustraliansC.theEnglishmen()4.BoththeEnglishmenandtheAustralianknewthat.A.themoonwasmuchfartherawayfromourearththanthesunB.thesunwasmuchfartherawayfromourearththanthemoonC.thesunwasmuchhotterinthedaythanatnight()5.TheAustralianthoughtthat.A.thesunwasveryhotatnightB.thesunisnothotatnightC.thesunwastoocoldforpeopletogotoatnight(B)SpacecampingChildrenBetween9and11yearsoldActivitiesInthecamp,childrenwilllearnaboutastronauts’lifeinspace,eatspacefood,learntosleepandevengotothebathroominspace.Therewillbeastronauttraining,too.Childrenwillsitonthespecialchairtohavethetraining.Thechaircanmoveintheair.Childrenwilljoininwateractivities,butnottoomany.CostMeals,lodging(住宿)andactivities(campT-shirtforfree)Timetable7:00amCGetup8:00am-Breakfast9:00amto10:00amCTravel11:00amCWateractivities11:30am-Travel1:00pmCLunch2:00pmto2:30pmCRocketlaunching(发射)4:00pmto5:00pmCTeamtime6:00pmCSupper7:00pmCGames9:00pm-Gotobed()6.Childrenattheageof_______canjointhespacecamp.A.eightB.tenC.twelveD.eighteen()7.Childrendon’tneedtopayforthe_______.A.lunchB.lodgingC.activitiesD.campT-shirt()8.Afterteamtime,childrenwill_______first.A.havesupperB.playgamesC.launchtherocketD.gotosleep()9.Fromthetimeable,wedon’tknowwhatchildrenwilldoat_______.A.9:30amB.11:00amC.3:00pmD.9:00pm()10.WhichofthefollowingisTRUEaccordingtothepassage?A.Childrenwilltraveltothemoon.B.Childrenwillhaveastronauttraningonthesofa.C.Childrenwilllearnhowtogotothebathroominspace.D.Childrenwilljoininalotofwateractivities.六、书面表达预测一下50年以后的中学生生活，与现在相比有怎样的变化，用英语写一篇50～80字的短文。Students’lifein50years一、单词拼写1-5scientistalreadyboredhumansseems6-10astronautRocketsspaceableimpossible二、1.willbe2.took3.issinging4.willbe5.Will,buy6.better7.fewer8.tobe9.more10.tostudy三、选词填空1-5littlealittlefewlessmore或morelessmuch6-10moreMoremoremanymanymore四、单项选择1-5BBACA6-10DDDDB11―15CCBAD16-20BCADA21-25BAAAB26-30ACA五、阅读理解1-5ACABB6-10BDACC六、OnepossibleversionStudents’lifein50yearsIthinkstudents’lifein50yearswillbequitedifferentfromourstoday.Theywillnotgotoschooltohaveclasses.Theywillstayathometostudyoncomputers.TheywillasktheirteachersorclassmatesforhelpbychattingontheInternet.Theywon’tusepaper,pensorexercisebooks.Theywillgotoschooltohavesportstogether.Forexamples,theywillgotoschooltoplayballgames.Idon’tlikethatkindoflife.Iliketomeetmyteachersandclassmateseveryday.
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or not , or to not
不可能；没有用；办不到；不成功
to get her to come down from the , but it was no go.
他们费了好几个小时的工夫想把她从房顶上弄下来，还是没成功。
因为天气原因发射没有成功。
Unachievable
Translations of “be no go”
in Chinese (Traditional)
(Definition of be no go from the
(C) Cambridge University Press)
be no go idiom
Add Cambridge dictionaries
Definitions of “be no go” in other dictionaries
existing or happening in all parts of a particular country
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Take it away! (Phrasal verbs that use ‘take’)
by Kate Woodford,
Continuing with our occasional series on the subject of phrasal verbs, we look this week at ones formed with the verb ‘take’. Phrasal verbs are extremely common in English. That is why teachers are so keen to teach them even to beginners. One of the first phrasal verbs that students of English
bro-country noun
a sub-genre of country music sung by young white men, featuring songs with macho themes such as trucks, drinking, and partyingSoftware Tools for Technology Transfer manuscript No. (will be inserted by the editor) Chec56
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Software Tools for Technology Transfer manuscript No. (will be inserted by the editor) Chec56
Software(willbeinsertedT；TransfermanuscriptNo.Che；Robby1,EdwinRodr′?guez1,；,John；Hatcliff；DepartmentofComputingand；e-mail:{robby,edwin,hatc；DepartmentofComputerScie；e-mail:dwyer@cs
Software(willbeinsertedToolsforbyTechnologytheeditor)TransfermanuscriptNo.CheckingJMLSpeci?cationsUsingAnExtensibleSoftwareModelCheckingFramework??Robby1,EdwinRodr′?guez1,MatthewB.Dwyer2,JohnHatcliff11DepartmentofComputingandInformationSciences,KansasStateUniversity????e-mail:{robby,edwin,hatcliff}@cis.ksu.edu2DepartmentofComputerScienceandEngineering,UniversityofNebraska-Lincoln??????e-mail:dwyer@cse.unl.eduAugust5,2004Abstract.Theuseofassertionstoexpresscorrectnessprop-ertiesofprogramsisgrowinginpractice.Assertionsprovideaformoflightweightcheckablespeci?cationthatcanbeveryeffectivein?ndingdefectsinprogramsandinguidingde-veloperstothecauseofadefect.Awidevarietyofassertionlanguagesandassociatedvalidationtechniqueshavebeende-veloped,butrun-timemonitoringiscommonlythoughttobetheonlypracticalsolution.Inthispaper,wedescribehowspeci?cationswrittenintheJavaModelingLanguage(JML),ageneralpurposebe-havioralspeci?cationlanguageforJava,canbevalidatedus-ingacustomizedmodelcheckingframework.Ourexperienceillustratestheneedforcustomizedstate-spacerepresentationsandreductionstrategiesinmodelcheckingframeworksinor-dertoeffectivelycheckthekindofstrongbehavioralspeci-?cationsthatcanbewritteninJML.Wediscusstheadvan-tagesofmodelcheckingrelativetootherspeci?cationvalida-tiontechniquesandpresentdatathatsuggestthatthecostof??ThisisanextendedversionofthepaperCheckingStrongSpeci?ca-tionsUsingAnExtensibleModelCheckingFrameworkthatappearedinPro-ceedingsofthe10thInternationalConferenceonToolsandAlgorithmsfortheConstructionandAnalysisofSoftware,TACAS2004.ThisworkwassupportedinpartbytheU.S.ArmyResearchOf?ce(DAAD),byDARPA/IXO’sPCESprogram(AFRLContractF33615-00-C-3044),byNSF(CCR-0306607)byLockheedMartin,andbyRockwell-Collins.????234NicholsHall,Manhattan,KS66506,USA.??????256AveryHall,Lincoln,NE68588,USA.modelcheckingstrongprogramspeci?cationsispracticalforseveralrealprograms.1IntroductionTheideaofinterspersingspeci?cationsoftheintendedbe-haviorofaprogramdirectlyinthesourcecodeisnearlyasoldasprogrammingitself[7].Thosefoundationalideasin-spiredthedevelopmentofmoreelaboratedesignpracticesandmethodologies,forexample,design-by-contract[18].Theuseofassertionalspeci?cationshaslongbeenregardedasameansforimprovingsoftwarequality,butonlyrecentlyhavestudiesdemonstratedsupportforthisconjecture[27].Theincreasingnumbersofmodernlanguages(e.g.,Java,C#,PHP)andimplementationframeworks(e.g.,MFC)thatin-cludesimpleassertionmechanismssuggeststhattheyarepoisedto?nallyhavingthepracticalimpactthatwaspredicteddecadesago.Toful?llthispromise,thereisaneedforprogramasser-tioncheckingmechanismsthatarecost-effective,automatic,andthoroughinconsideringbothspeci?cationandprogrambehavior.Run-timemonitoringofassertionsduringprogramexecutionistheonlymechanismthatiswidelyusedinprac-ticetoday.Itisbothcost-effectiveandautomatic,butonlyreasonsabouttheprogrambehaviorsthatareactuallyexe-cuted.Thislackofcoverageofprogrambehaviorisasig-ni?cantweaknessofrun-timemethods,especiallyforcon-currentprogramswheresubtleerrorsmaydependontheor-derinwhichthreadsexecute.Toaddresstheprogrambehav-iorcoverageproblem,avarietyofstaticanalysisapproacheshavebeenproposedtothoroughlycheckaprogram’spossiblebehaviorswithrespecttocertainlightweightspeci?cations,suchas,pointernull-nessandarraybounds[6]andproposi-tionaltemporalproperties[31].Thesemethodsgainprogramcoveragebysacri?cingtheexpressivenessoftheirspeci?ca-tionlanguage.Buildingonalong-lineofworkonformalmethodsformanualreasoningaboutcompletebehavioralspeci?cationsofprograms,severalrecentlanguageshaveemergedthatbal-ancethedesireforcompletenessandthepragmaticsofcheck-ability.TheJavaModelingLanguage(JML)isonesuchlan-guage[15].WithJMLonecanspecifypropertiesofvaryingstrengthfromlightweightassertionsaboutpointernull-nesstocompletefunctionalcorrectnesthelatterwerefertoasastrongproperty.JMLisabehav-ioralinterfacespeci?cationlanguagethatallowsdevelopers2Robbyetal.:CheckingJMLSpeci?cationsUsingAnExtensibleSoftwareModelCheckingFrameworktospecifyboththesyntacticandbehavioralinterfaceofaportionofJavacode.Itsupportsthedesign-by-contract[18]paradigmbyincludingnotationforpre/post-conditionsandinvariants.JMLusesJava’sexpressionsyntaxandadds,forexample,constructsforquanti?cationoverobjectinstancesandforexpressingdetailedpropertiesofheapallocateddata.Thisallowsdeveloperstocreateverynaturalandcompactstatementsofstrongspeci?cationsofthebehaviorofJavaprograms.Inthispaper,wedescribehowwehaveadapteda?exiblemodelcheckingframeworkcalledBogor[23]tocheckJMLspeci?cationsofsequentialandconcurrentJavaprograms.Modelcheckingaddsanewandcomplementaryapproachtotheexistingrun-timeandtheorem-provingtechnologiesforreasoningaboutJML.Whiletoolsbasedonthosetechnolo-gieshaveproveneffectiveinsupportingcertainkindsofJavavalidationandveri?cationactivities,thereiscurrentlynoau-tomatictechniqueforthoroughlycheckingawide-rangeofstrongJMLspeci?cationsespeciallyinthepresenceofcon-currency.OurcheckingtoolisautomaticandexhaustiveinitsreasoningaboutgeneralJMLpropertiesuptouserde?nedboundsonthespaceconsumedbyaprogramrun.Previousworkonusingmodelcheckingtoverifystrongerspeci?cationhasachievedonlylimitedsuccessforseveralreasons.First,existingmodelcheckers,suchasSpin[11],donotprovidedirectsupportformodelingdynamicallyallo-catedobjectsandheapstructuresmakingitdif?culttoevenrepresenttheprogram’Bogormaintainsanex-plicit,yetcompact,representationofthedynamicprogramheap[25].Second,evenifonecouldencodethebehaviorintheinputlanguageofsuchamodelchecker,theunderlyingcheckingalgorithmswouldnotexploitthesemanticprop-ertiesoftheoriginallanguagetooptimizBogorincorporatesnovelpartialorderreductionsthatexploitthesemanticsofaprogram’sheapandlockingstruc-turetoachieveef?ciency[3].Finally,existingmodelcheck-ingframeworkssupporttemporalpropertiesbutdonotpro-videdirectsupportforexpressingrichdataorheap-relatedBogorsupportsextensionviauserde-?nedatomicexpressionsthatcanbeevaluatedoverthefullextentofaprogramstateincludingtheheap[23].Thecontributionsofthispaperareasfollows:Cwedemonstratethatwithasuf?cientlyfeature-richmodelcheckingframeworkonecancheckstrongbehavioralspec-i?CwedescribehowBogor’sextensionfacilitiescanbeap-pliedtoimplementcheckingofJMLspeci?cations,in-cludingspeci?cationsthathaveprovendif?culttocheckbyothermeanssuchasrun-timecheckingortheorem-andCwedemonstratethattheoverheadofcheckingJMLspec-i?cationscanbemitigated,andinmostcasescompletelyeliminated,throughtheuseofsophisticatedstate-spacereductions.Inthenextsection,wegiveanoverviewofBogorandsur-veyexistingtechnologiesandtoolsforreasoningaboutJMLspeci?wealsodiscussnon-JMLbasedapproaches.Section3introducesaJMLannotatedJavaexamplethatwillbeusedtoillustratetheanalysistechniqueswehavedevel-oped.Section4detailsourstrategyforef?cientlyreasoningaboutJMLspeci?cationson-the-?yduringstate-spaceexplo-rationofaconcurrentJavaprogram.InSection5,wedetailtheanalysisofacollectionofJMLannotatedJavaprogramsandreportonthecostandeffectivenessofcheckingthemwithBogorandthenconclude.2BackgroundandRelatedWork2.1BogorBogor[23]isanextensibleandhighlymodularsoftwaremodelcheckingframeworkthatcanbeadaptedandcustomizedtothespeci?ccharacteristicsofdifferentproblemdomains.Forexample,Bogorhasbeencustomizedtoexploitdomain-speci?cfeaturesintheveri?cationofavionicssystems[4].OneofthefeaturesthatmakesBogor?exibleistheex-tensibilityofitsmodelinglanguage,BIR[23].Incontrasttoothermodelcheckerinputlanguages,BIRfeaturesanexten-sionlanguagefacilitythatallowsintroductionsofnewAb-stractDataTypes(ADTs)andabstractoperationsas?rst-classconstructsofthelanguage.Theseintroductionsareanal-ogoustoaddingnewnativetypesandnativeinstructions,sotheycanessentiallybeusedtobuildabstractmachinestai-loredtospeci?capplicationdomains.Inadditions,manyop-timizationscanbedoneinBIRlanguageextensionssuchasremovingunnecessarydetailsfromADTbit-vectorstaterep-resentationsandsymmetryreductions.Figure1showsthemechanismforextendingtheBIRlan-guage.The?guregivesaglanceattheBIRsyntaxdisplayingasimplesystemthatmodelsanenvironmentinwhichthereareseveralprocessescompetingforresourcesinaresourcepool.Forthisparticularsystem,weonlycareaboutmember-shipoperationsontheresourcepool,thus,wecreateanewSetADTtomodelthispoolofresources.Todothis,thekey-wordextensionisusedtodeclaretheextensionname.TheRobbyetal.:CheckingJMLSpeci?cationsUsingAnExtensibleSoftwareModelCheckingFrameworksystemResourceContention{extensionSetformyPackage.SetModule{typedeftype&’a&;expdefSet.type&’a&create&’a&(’a...);expdef’achoose&’a&(Set.type&’a&);expdefbooleanisEmpty&’a&(Set.type&’a&);expdefbooleanforAll&’a&(’a?&boolean,Set.type&’a&);actiondefadd&’a&(Set.type&’a&,’a);actiondefremove&’a&(Set.type&’a&,’a);}recordResource{booleanisF}recordDiskextendsResource{}recordDisplayextendsResource{}Set.type&Resource&resourcePfunisResourceFree(Resourceresource)returnsboolean=resource.isFfunAreAllResourcesInPoolFreeInv()returnsboolean=Set.forAll&Resource&(isResourceFree,resourcePool);mainthreadMAIN(){locloc0:do{//createthepoolandcreatestwoprocessesresourcePool:=Set.create&Resource&(newDisk,newDisk,newDisplay);startProcess();startProcess();}}3threadProcess(){locloc1:invokerun()}functionrun(){Rlocloc2:when!Set.isEmpty&Resource&(resources)do{//chooseanelementandremoveitresource:=Set.choose&Resource&(resourcePool);Set.remove&Resource&(resourcePool,resource);}gotoloc3;locloc3:do{//resourceinuseresource.isFree:=}gotoloc4;locloc4:do{//resourcefreeresource.isFree:=}gotoloc5;locloc5:do{//addtheresourcebacktopoolSet.add&Resource&(resourcePool,resource);}gotoloc2;do{//emptytransformation}gotoloc2;}}Fig.1.ResourceContentionExampleforkeywordprovidesthefullyquali?ednameoftheclassthatimplementstheextension.Theimplementationoftheex-tensionoperationsisdonebyfollowingacleanandwellde-?nedAPIusingwidelyknowndesignpatterns[8].Theselan-guageextensionfacilityisusedasavehicletode?neJMLconstructsdirectlyinBIR;ThoseextensionsarepresentedinSection4.2.2JML:TheJavaModelingLanguageTheJavaModelingLanguage(JML)[15]isaBehavioralIn-terfaceSpeci?cationLanguage(BISL)[32]designedatIowaStateUniversitybyGaryLeavensandothers.InJML,therearetwowaysonecanspecifypropertiesofprograms,i.e.,byusinglightweightspeci?cationsorheavyweightspeci?ca-tions.Thedifferencebetweenheavyweightandlightweightspeci?cationsisonhowmethodsareannotated(independentlyofclasslevelannotations:invariants,axioms,etc.).Aspeci-?cationisheavyweightaslongasitisannotatedusingoneofthebehaviorkeywords(behavior,normalorexceptional),otherwisethespeci?cationislightweight.InJML,theinterfaceofamethodisspeci-?edusingasetofdifferentclauses,eachofwhichrepresentadifferentaspectofthebehaviorofthemethod.Themostimportantclausesare:Crequires:Usedtospecifytheconditionsthatthecallersofthismethodmustsatisfy.Censures:Speci?estheconditionsthatthismethodmustguaranteetoitscallers.AnotherimportantformofBogorextensionismoduleex-tension.Figure2showsasketchofBogor’sarchitecture.ThecomponentsintheModelCheckingComponentsareaofthe?gure,arelooselycoupledandcommunicatewitheachotherthroughwellde?nedinterfaces.Theyareallloadeddynam-icallybyreadingthelocationoftheirimplementingclassesfromauserde?nedcon?guration?le.Therefore,changingtheframeworkbehaviorisaseasyasprovidingadifferentimplementationforagivenmodulethatiscustomizedtoaspeci?cdomain.ThissecondtypeofextensionisneededtoimplementJMLoperators,especiallythosethatneedtoin-spectthestateoftheheapandaccesshistoryinformation.4Robbyetal.:CheckingJMLSpeci?cationsUsingAnExtensibleSoftwareModelCheckingFrameworkBogorFront?EndLexer.birParserIExpEvalType Checking.configSemanticsAnalysesIValueFactoryISchedulingSIStateFactoryITransformerISearchercounterexampleModel Checking ComponentsIActionTakerIBacktrackIFIStateMgrVerifiedFig.2.BogorArchitecture.Cdiverges:Speci?esaconditionthat,whentrue,makesthismethoddiverge,i.e.,neverreturntoitscaller.Cassignable:Usedtospecifyframeconditionsbypro-vidingalistofmemorylocationsthatcanbemodi?edbythismethod.Cwhen:Speci?esanenablingcondition:whencalled,thismethodshouldonlyproceedexecutioniftheconditionspeci?edistrue,otherwise,itshouldblockuntilitistrue.Csignals:Usedtospecifyexceptionalbehaviors.Anex-ceptiontypeandaconditionisgiven.Thesemanticsisthat,ifanexceptionofthegiventypeisthrown,thentheconditionmustbetrue.Heavyweightspeci?cationsarecalledsuchbecausetheyareassumedtobecomplete:ifthespeci?eromitsanyclause,theomittedclauseisgivenadefaultvalue.Incontrast,inlightweightspeci?cations,nothingisassumedaboutomittedclauses.Table1displaysthissituation.OneinterestingconsequenceofTable1isthatheavy-weightspeci?cations,bydefault,alwaysprovideadescrip-tionoftotalcorrectness:themethodmustalwaysterminate(i.e.,itsdivergesclauseistruebydefault).Ontheotherhand,inlightweightspeci?cations,unlessexplicitlystated,nothingisassumedabouttermination,thereforeitprovidesadescriptionofpartialcorrectness.OneofthemainfeaturesthathasmadeJMLappealingisitsJava-likesyntax.Infact,theJMLspecscanexploitJavacode,forexample,bycallingJavamethodsfromwithinaspeci?cation.Also,JMLprovidesarichlibraryofmodelclassesthatcanbeusedtoconstructrichabstractdescriptionsofprogrambehavior.Forexample,thelibraryincludesasetofdatastructuremodelclassesthatcanbeusedtomodelab-stractpropertiesofconcretedatastructures,inamoreconciseway,withoutunnecessaryimplementationdetails.Inaddition,thereisalsoarichsetofnativeoperatorsforde?ningcomplexspeci?cations,amongthemostimportantare:C\old(e):usedonlyinthespeci?cationofpostcondi-tionsandallowsonetoaccessthevalueofexpressioneintheprestateofthemethod.C\reach(e):returnsasetwithalltheobjectsthatarereachablefrome(emustevaluatetoareferencevalue).C\forall,\exists:allowsonetostatepropertiesus-inglogicalquanti?cation,speciallyusefultoquantifyoverallorsomeoftheobjectsintheheap.ThesecharacteristicsaredrivingJMLasanemergingstan-dardassertionde?nitionlanguageforJava.2.3ToolSupportforJMLVeri?cationBurdyet.al.[1]surveythesteadilygrowingbodyoftoolsup-portforreasoningaboutJMLspeci?cations.Ingeneral,therearethreeunderlyingtechnologiesusedinthesetools:semi-automatedtheoremproving,automateddecisionprocedures,andrun-timemonitoring.Thesetechnologieshavedifferentadvantagesanddisadvantageswhichweassessalongfourdi-mensions:Automation/UsabilityHowmucheffortisneededtousethetechnologyortool?JMLCoverageHowmuchoftheJMLlanguageissupported?BehaviorCoverageHowmuchofaprogram’sbehaviorisconsideredinreasoning?ScalabilityHowdoesreasoningcostgrowwithsystemsizeandcomplexity?Table2summarizesthestrengthsandweaknessesofthebasictechnologiesintermsofthesedimensions.Wecitespe-ci?ctoolsthatimplementJMLreasoningwiththosetech-nologies,butthestrengthsandweaknessesmentionedare,Robbyetal.:CheckingJMLSpeci?cationsUsingAnExtensibleSoftwareModelCheckingFrameworkOmittedClauserequiresdivergesassignablewhenensuressignalsLightweight\notspecified\notspecified\notspecified\notspecified\notspecified(Exception)\notHeavyweighttruefalse\everythingtruetrue(Exception)true5Table1.DefaultvaluesforJMLclausesinlightweightandheavyweightspeci?cations.forthemostpart,characteristicsoftheunderlyingtechnol-ogy.Wenotethatdespitetheirweaknesseseachofthesetoolsisusefulinthattheyhavebeenusedto?nderrorsinrealJavaprograms.LOOP[30]isthemostmaturetheorem-prover-basedJMLreasoningsystem.IttranslatesJMLspeci?cationsandJavasourcecodeintoproofobligationsforthetheoremproverPVS[20].Thus,thesemanticsoftheJavacodeaswellasJMLspeci?cationsarerepresentedasPVStheories,andusersverifythespeci?cationsagainsttheJavacodebyinteract-ingwiththePVScommand-lineinterfacetodischargethegeneratedproofobligations.LOOPisdif?cultfornovicestousesinceitrequiresdetailedknowledgeoflogicalrep-resentationofJavasemantics.RecentadvancesinLOOP’sweak-preconditioncalculusallowmethodswithstraight-linecodeperformingintegercalculationstobeveri?edwithlittleornouserinterventionbyleveragingtheunderlyingnumer-icalproceduresofPVS.LOOPscalespoorlytogeneralJavaapplicationsduetothecomplexitiesofitslogicaltreatmentofaliasing.Withsuf?cientexpertise,however,LOOPallowsverystrongcorrectnesspropertiestobeestablishedwiththehighest-possibledegreeofcon?dence.ESC/Javaisanothertheorem-prover-basedtoolforasub-setofJML.ESC/JavaallowstheusertoworkattheJavalevelbyencapsulatingthetranslationofveri?cationcondi-tionstoanunderlyingtheoremprover.ItgainsahighdegreeofautomationbytreatingasmallsubsetofJMLandbysac-ri?cingprecisionintheresultsofitsanalysis.ESC/Javatar-getstheef?cient,automaticcheckingofnullreferencesandsimpleintegerproperties(e.g.,arrayboundsviolations),butdoesnotsupportricherproperties,forexample,thosethatre-quirequanti?cationoverclassinstancesoranyofJML’sheaprelatedprimitives.Itusesamodularcheckingapproachinwhichmethodsareveri?edinisolationbytryingtoprovethatclassinvariantsandmethodpost-conditionsholdundertheassumptionthatthemethod’spre-conditionsaresatis?ed.ES-C/Javaisfullyautomaticanditsmodularcheckingapproachallowsittoscaletolargeprograms(e.g.,upto50Klinesofcode).CheonandLeavens[2]havedevelopedarun-timechecker(jmlc)whichcompilesJML-annotatedprogramsintobyte-codethatincludesrun-timeassertionstocheckJMLspeci?-cations.Aswithotherrun-timeanalysismethods,reasoningusingjmlcrequiresacompleteJavaprogram,thusifasingleclassormethodistobeanalyzedanappropriatetestharnessmustbeconstructed.Asidefromthis,usingjmlcisfullyautomaticforagoodportionoftheJMLnotablylackingaregeneralsupportforclassinstancedomainsandaccesstopre-conditionstatevaluesinpost-conditions.jmlcimplementsrun-timecheckingontopofexistingJVMsandconsequentlyitprovidesnodirectsupportformulti-threadedprograms.2.4OtherRelatedWorkTherehavebeenanenormousnumberofeffortstode?nelan-guagesforspecifyingandreasoningaboutprogrambehavior.Weareinterestedinprovidingautomatedreasoningsupportforstrongpropertiesofmodernconcurrentobject-orientedlanguages,thus,mostoftheexistingworkonsimpleasser-tionlanguagesandmanualformalmethodsislacking.RecentworkonOCLandAlloyisaimedatsupportingatleastsomeofourgoals.SpaceconstraintsdonotpermitadetaileddiscussionofthedifferentcheckingmechanismsthathavebeenproposedforOCL.Onelineofwork,e.g.,[12],issimilartojmlcinthatitgeneratesrun-timeassertionsforcheckingJava.An-otherpopulardirectionistocompareOCLspeci?cationswithotherUMLmodels,e.g.,[22],ratherthanprogramsourcecode,thusanumberoftheissuesregardingreasoningaboutheap-allocatedprogramdataarenotconsideredinthatwork.TheAlloyAnnotationLanguage(AAL)[13]isalanguageforannotatingJavacodewithasyntaxthatissimilartoJML.AALsupportsanalysis,viaboundedsatis?abilitychecking,ofloop-freecodesequencesthatmayhavemethodinvoca-包含各类专业文献、各类资格考试、应用写作文书、外语学习资料、高等教育、专业论文、行业资料、Software Tools for Technology Transfer manuscript No. (will be inserted by the editor) Chec56等内容。　
　 Astronomy & Astrophysics manuscript no. aa2792 (DOI: will be inserted by hand later) February 2, 2008 Line pro?les of molecular ions toward the pre... 　 Astronomy & Astrophysics manuscript no. lachaume (DOI: will be inserted by hand later) February 5, 2008 Resolving the B[e] star Hen 3-1191 at 10 ... 　 A&A manuscript no. (will be inserted by hand later) Your thesaurus ... as well as the intricacies of radiative transfer (see an overview in ...}