MOSQUITO 1.5 User Manual
Contents
1. assm mean 0 2 s 7 Q 2 read tatus lt lt PAhost gt gt a DeliveryOrderProcess PAschdPolicy FIFO lt lt PAstep gt gt readStatus PAdemand assm mean 0 1 s PAstep gt createNewOrder PAdemand assm mean 0 15 s a if Y lt PAhost gt gt real tus createNewOrder CatalogServer il PAschdPolicy FIFO lt lt component gt o CustomerProcess lt lt PAstep gt gt updateStatus PAdemand assm mean 0 2 s isa po atus FP s lt PAstep gt gt readStatus PAdemand assm mean 0 1 s lt lt PAstep gt gt browseCart PAdemand assm mean 0 8 s PA 0 Y lt lt PAstep placeOrder PAdemand C assm mean 0 browseCart lt lt PAstep gt insertitem PAdemand assm mean 0 8 s lt lt PAstep gt deleteltem PAdemand asso mean 0 8 s A m lt lt PAstep gt gt browseCatalog PAdemand assm mean 0 8 s placeOrder lt lt PAhost gt gt La CartServer updat PAschdPolicy FIFO lt lt PAstep gt gt updateStatus PAdemand assm mean 0 3 s Cy lt PAstep gt gt readStatus PAdemand assm mean 0 2 s T a d tus O A daem PAho2. b c 15 Translation rules for the alternative fragmetn Time I m1 a b t1 mal t3 t4 ma ts m2 bc t2 m3 bc t4 loop condition Translation rule for the loop fragments 34 por region m30 a c t2 m4 c a t3 m5 a bt4 Translation rule for the parallel fragments For what concerns Sequence Diagram fragments the following mapping is adopted The Reference operator corresponding at the key word Ref denotes that a Sequence Diagram includes a defined behaviour in another Sequence Diagram This is translated so that the queuing network corresponding to the first diagram merges the sub net corresponding to the second diagram The alternative operator corresponding at the key word Alt denotes the presence in the diagram of a choice between two behaviours or more simply the choice to execute or not a specific behaviour The methodology translates the operator as a net branching point with probabilities associated to the matching patterns The Parallel operator corresponding at the key word Par denotes two or more different patterns to be executed in parallel It is translated with a pair of fork join nodes in the network The methodology is able also to translate other operators as described in 1 that are not yet implemented in MOSQUITO 39
3. q E ma f A ge n 7 use case n gt Sig o e user m Pu 1 Figure 15 Generically annotated UCD Let us suppose to have a UCD with m types of users and n use cases Let p i i 1 m be the ith user type probability of usage of the software system i e lt lt REuser gt gt REaccessprob We have that Yp 1 Let qij j 1 n be the probability that the ith user makes use of the software system by executing the use case j i e lt lt REserviceUsage gt gt REserviceprob We have that a 0 1 The probability for whatever scenario j described by means of a Sequence Diagram SD associated to the UseCase j to be executed is then given by P Y p Oq 1 i l This can be equivalently expressed as REprobpesenice gt REaccessprobxryse REserviceprob 1 REuser REservice i i l Sequence Diagram processing and meta Eg building In this step an algorithm is used to transform all the Sequence Diagrams in an Execution Graph that is called a meta EG 2 The meta EG is a platform independent annotated Execution Graph The idea of the algorithm it is to apply the following translating rules for Sequence Diagram patterns 33 Sequence Diagram Execution Graph time mi a b t1 mig b 0 12 Translation rule for the sequential steps 3 55 0 mi0a b 01 t LE i i m2 b c t2 t2 ife t4 ts J m3 b c 13 gt m
4. Message used on activate the ph in the the two uml InteractionOperand UM CombinedFragment man With probability 1 value the i e ifand then operands of the VALI A is aan to the first PAprob value Alt uml CombinedFragment message following the alt compartment lt lt PAstep gt gt It denotes the number of the On bs isle hae iterations in the loop fragment PArepetitionFactor HOOP value uml CombinedFragment Table 4 Prima UML Stereotypes used on SD 24 It is worth to note that the lt lt PAstep gt gt stereotype is applied on the first message of the Alt uml CombinedFragment in the same manner as the SapeOne methodology 6 4 2 1 Assumptions The only difference with the SAPone methodology is described here below 1 You must specify a Sequence Diagram for each use case in the Use Case Diagram In order to associate the Sequence Diagram at the Use Case you must create it as a child in the Uml2 tree hierarchy as showed in the example here below GEE B Data 7 Relations B E 001 Use Cases and Scenarios UCDs and SDs Relations use Case Diagram Customer lt lt REuser gt gt BrowseCart A SCARERSE Di agram 8 4 BrowseCart if CallEvent BrowseCart Browsetart M CallEvent ReadStatus_1 RedStatus M CallEvent M CallEvent BrowseCart E Actor 002 Software Architecture CDs CustomerProcess 002 Software Architecture C
5. can be solved to obtain performance measures keeping into account the software and the hardware characteristics 4 Any UML tool exporting in Eclipse pai and UML 2 UseCase quence boaan Prima UML pony Prima UML n EG Generation QN generation Platform Diagrams Independent Platform Model Specific Model SAPone QN generation i PMIF based SPMIF based _ PMIF based EG model SE Po Doe QN model Software fra e SRG Architectural Performance Sotware modei Si c Performance Model oe alatiorm Model Model SAP one Prima UML i PMIF based Y QN Model Parametrized 7 QN Solver HW SW 7 Performance Model Platform Platform under development ste Independent Specific P Indices Indices Figure 7 The performance analysis process carried out by Mosquito 4 The Sap One methodology SAP one 1 is a methodology for the performance modelling of a software system It consists essentially in the annotated generation of a queuing network from an UML architectural model SAP one has been conceived to be applied in the first phases of the software process to reveal architectural flaws as soon as possible so the developer will be able to modify the system architecture The UML model is enriched with additional information regarding the system performance such as scheduling policies and service times of software components In this approach the service centers of the queuing network don t represent
6. on Semantic UML metaclasses A processing resource is a lt lt PAhost gt gt device which has processing CPU steps allocated to it PAschdPolicy value PArate value PAmultiplicity value On uml Node PAmultiplicity defines how many instances of the CPU resource are available on the containing uml Node lt lt PAresource gt gt PAmultiplicity value On uml Node A passive resource represents a resource protected by an access mechanism e g a semaphore which is accessed during the execution of an operation PAmultiplicity defines how many instances of the DISK resource are available on the containing uml Node lt lt PAresource gt gt TERMINAL PAmultiplicity value On umi Node It represents users jobs that access the containing node PAmultiplicity defines how many users jobs access the containing uml Node lt lt PAresource gt gt PAaxTime value On uml Node It represents a network i e LAN WAN connecting two Node PAaxTime specifies the delay introduced by the network communication 6 5 2 1 Assumptions Table 5 Prima UML Stereotypes used on DD The hardware resources supported from the methodology are the CPU the DISK the TERMINAL and a DELAY resource representing network connections The assumptions on the input model are as follows 1 Only one Terminal resource must appear in the model A Terminal resource must be speci
7. removed M 1 5 Distribuited SOAP version Zipped Stream Output Queuing Networks SAPone Queueing Netowrks Prima UML Execution Graphs Prima UML g Figure 1 Mosquito versioning The last MOSQUITO release i e M 1 5 is able to build besides Execution Graphs and QN at the software level also QN at the platform level that can be combined with Execution Graphs for detailed parameterization The MOSQUITO input has been extended to include an Eclipse UML v2 annotated Deployment diagram in agreement with the requirements of Prima UML methodology The current release of MOSQUITO provides a log error feedback that is very useful to locate a problem in the input model The following picture show all the use cases that MOSQUITO 1 5 provides to the users 2 Getting Started MOSQUITO MOdel driven conStruction of QUeuIng neTwOrks is a tool developed in JAVA language as plugin for the Eclipse Platform To use it you need to install a Java Virtual Machine and the Eclipse Platform with Eclipse UML 2 1 Installation Requirements Server Side Operating System Independent Web Application Container Apache Tomcat 6 0 with Axis2 1 4 JDK version 1 5 or higher Client Side Eclipse 3 2 or higher Eclipse EMF 22 Eclipse UML2 2 JDK version 1 5 or higher 2 2 Getting Eclipse with Eclipse UML The main Web site for Eclipse is www eclipse org On that page you can see the latest Eclipse news and links to a variety of online
8. resources including articles newsgroups bug tracking and mailing lists The latest version of Eclipse can be downloaded from the main download page at www eclipse org downloads if this site is unavailable a number of mirror sites around the world are available Go ahead and download the latest release or stable build The download page for each release includes various notes concerning that release as well as links to every platform version Eclipse supports a large number of platforms including Windows Linux Solaris HP Mac OSX and others Choose the Eclipse SDK download link corresponding to your platform and save the Eclipse zip file to your computer s hard drive This will generally be a very large file gt 105 MB so be patient unless you have sufficient bandwidth available to quickly download the file Once the Eclipse zip file has been successfully downloaded unzip it to your hard drive Eclipse does not modify the Windows registry so it does not matter where it is installed MOSQUITO was developed with Eclipse 3 2 and subsequently tested with Eclipse 3 2 and higher It is very important to download a version of Eclipse with the Eclipse UML plugin already installed to create the UML models that represent the input to MOSQUITO However if you already have an Eclipse installation without Eclipse UML plugin you can update your platform with the update manager selecting Help gt Software Updates gt Find and Install gt Sea
9. Architectur nd Scenarios age Operation 4 The first CallMessage of each Sequence Diagram must be stereotyped with the lt lt PAClosedLoad gt gt stereotype 23 5 The first message entering in each operand of an alternative fragment must be stereotyped with the lt lt PAstep gt gt stereotype using the PAprob tag This tag indicates the probability to invoke all the Call Messages into the fragment operand This value must fall between zero and one 6 For every used fragment in the sequence diagrams you must specify the first and the last message id properly contained in the fragment This operation must be performed using the firstMessage and lastMessage tags of the stereotype Interaction Operand as showed in the example here below PA ETTI EE E e 1 Customer Process CartSerwer DelveryOrderProcess OrderServer Customer Ser 5 Profile lt ALL gt select 2 Rows tutus 8 l and Tina kb ves cick Fa fiestMessage 4 Resta 2 lostMessage 11 lt P atep gt PApeob Spenod 5 G Creme Maeve gt Ti NewOrderi a LI 9 10 Updatestatus gl di Back Help 6 4 2 Prima UML annotations The Sequence Diagram must be enriched with the information in the following table Stereotype Syntax Apply Stereotype on Semantic UML metaclasses lt lt PAstep gt gt It denotes the probability to On the first uml
10. Commerce System Figure 8 shows the system structure at a high level of details In a first analysis some databases Customer DB Cart DB Order DB etc and four process type CustomerProcess SupplierProcess etc are identified For each involved database there is a server that permits to communicate with 1t The interactions with these servers are asynchronous Each customer has associated a individual CustomerProcess If the customer is not registered the process allows the browsing of the catalogue only whereas if he is a registered one the process activates all the functionalities the system provides him cart managing order placement etc All the functionalities provided by the system to the supplier instead are coded in the SupplierProcess The DeliveryOrderProcess and InvoiceProcess are processes that manage the activities to be executed to dispatch an order and to produce the corresponding invoice In the system one DeliveryOrderProcess instance and one Invoice Process instance are running any time for each order and for each invoice in process respectively Generating an Eclipse UML2 model uml as input to Mosquito implies a more detailed description using the terms used by the OMG UML 2 1 Superstructure specification e g the names used for metaclasses and their tags and by an UML2 SPT profile e g names used for stereotypes and their tags That kind of detailed and precise should allow a tighter mapping between the Impo
11. Ds CartServer Call Message BrowseCart lt lt PAclosedLoad gt gt 4 Call Message ReadStatus_1 gt Reply Message gt Reply Message Actor 002 002 vare Architecture B browseCatalog ID Nalataltam vare Architecture CDs CustomerProcess 5 CartServer 6 5 Deployment Diagram A Deployment Diagram shows the configuration of run time processing elements and the software components that live on them It is a graph where nodes i e the processing elements uml Node are connected by communication path i e uml CommunicationPath Nodes can contain artifacts uml Artifact that manifest components see Figure 12 Therefore a DD shows the mapping of components on processing elements see Figure 13 25 lt lt PAhost gt DT CustomerProcess PAschdPolicy FIFO lt PAstep gt browseCant PAdelay assm mean 0 8 5 ssPAstep gt placeOrder PAdelay assm mean 0 8 s lt lt PAstep gt gt insertitem PAdelay assm mean 0 8 s lt lt PAstep gt gt deletettem PAdelay assm mean 0 8 s lt lt PAstep gt gt browseCatalog KPAdelay assm mean 0 8 s lt PAhost gt zj DeliveryOrderProcess PAschdPolicy FIFO lt PAstep gt gt readStatus PAdemand assm mean 0 1 s lt lt PAstep gt createNewOrder PAdemand assm me
12. MOSQUITO 1 5 User Manual SEAlab Software Quality Group Dipartimento di Informatica Universita dell Aquila May 2008 1 MOSQUITO VERSIONING 2 GETTING STARTED 2 1 Installation Requirements 2 2 Getting Eclipse with Eclipse UML 2 3 Installing MOSQUITO 3 MOSQUITO AT A GLANCE 4 THE SAP ONE METHODOLOGY 5 THE PRIMA UML METHODOLOGY 6 MOSQUITO AT WORK 6 1 eCommerce System Specification 6 2 Use Case Diagram 6 2 1 Sap One annotations 6 2 2 Prima UML annotations 6 3 Component Diagram 6 3 1 SapOne annotations 6 3 2 Prima UML annotations 6 4 Sequence Diagram 6 4 1 Sap One annotations 6 4 2 Prima UML annotations 6 5 Deployment Diagram 6 5 Sap One annotations 6 5 2 Prima UML annotations 7 REFERENCES 8 APPENDIX 8 1 Queuing Network process creation SAP one methodology 8 2 Execution Graph creation Prima UML methodology 10 10 32 32 32 1 Mosquito versioning The MOSQUITO 1 5 release provides new features that have been added to the previous version In particular now MOSQUITO can be invoked with different exports formats and a new functionality to completely execute the PRIMA UML methodology has been added The MOSQUITO evolution across the different releases is exposed in the picture here below Omondo XMI Eclipse UML2 v1 x Eclipse UML2 v2 x MOSQUITO Standalone version M 1 1 Distributed RMI version M 1 2 Distributed SOAP version M 1 3 Distributed SOAP version Error M 1 4 Distribuited SOAP version
13. REserviceprob 0 5 pi Provider REaccessprob 0 25 lt REseniseUsage gt gt y REserviceprob 0 16 gpeentandrae sexni 1 lt lt REserviceUsage lt lt REservice gt Insert Item to Catalogue REprob 0 05 REserviceUsage gt REserpiceprob 0 1 sREservicetlsage gt REserviceprob lt lt REservice gt Confirm Delivery REprob 0 049 REservibeUsage gt gt REserviceprab 0 07 ssREservice gt gt Payment amp Invoice REprob 0 075 ssREservice gt gt Browse Order Status REprob 0 049 REuser gt gt Bank REaccessprob 0 05 Figure 9 UCD of the eCommerce System with the operational profile The supplier maintains the catalogue by inserting new items from the catalogue InsertNewItemInCatalogue and deleting from it the items no more available 12 DeleteItemFromCatalogue Moreover she he processes the orders by delivering the items sold DeliveryOrder and producing the invoice after the customer has payed Payment amp Invoice In this last use case the bank actor is in charge for the money transfer from the customer bank account to the supplier one Again the use case diagram specifies that both InsertNewItemInCatalogue and DeleteItemFromCatalogue functionalities use the BrowseCatalogue in their execution For the sake of presentation in this document a simplified version of this system is
14. an 0 15 s s lt PAhost gt gt ca CatalogServer PAschdPolicy FIFO lt PAstep gt gt updateStatus PAdemand assm mean 0 2 s lt lt PAstep gt gt readStatus PAdemand assm mean 0 1 s s PAhost gt ca CustomerServer PAschdPolicy FIFO lt PAstep gt updateStatus PAdemand assm mean 0 3 s lt PAstep gt gt readinfo PAdemand assm mean 0 2 s lt lt PAhost gt gt CartServer PAschdPolicy FIFO lt PAstep gt gt updateStatus PAdemand assm mean 0 3 s lt lt PAstep gt gt readStatus PAdemand assm mean 0 2 s lt lt PAhost gt gt OrderServer PAschdPolicy FIFO lt lt PAstep gt gt newOrder PAdemand assm mean 0 1 s lt PAstep gt readStatus PAdemand assm mean 0 2 s lt lt PAhost gt Customerinterface PAschdPolicy FIFO lt lt PAstep gt gt browseCarReqO PAdelay assm mean 0 8 s lt lt PAstep gt placeOrderReq PAdelay assm mean 0 8 s lt PAstep gt gt insertitemReqO PAdelay assm mean 0 8 s ssPAstep gt gt deleteltemReg PAdelay assm mean 0 8 s s lt PAstep gt gt browseCatalogReg PAdelay assm mean 0 8 s lt manitest gt gt lt lt manitest gt gt lt manitest gt gt lt m
15. anitest gt gt lt manitest gt gt lt manitest gt gt lt manifest gt gt Figure 12 The artifacts that manifest each component szartifact gt gt D J szartifact gt gt DeliveryOrderProcess CustomerProcess Stub S lt lt deploy gt gt lt lt deploy gt Client IN uml CommunicationPath Server T lt lt debloy gt gt lt lt deploy gt gt y ij lt artifacte x lt lt artifact gt D T scartifec earstomerServer Customer Process Skeleton Orar Server ssdeploy gt lt lt deploy gt gt i ssartifacts gt s lt artifacts F j CartServer CatalogServer k IN uml Artifact Figure 13 Deployment Diagram Figure 12 shows the uml Artifacts that manifests uml Components see the lt lt manifest gt gt stereotyped dependency between the uml Component and its own uml Artifacts whereas Figure 13 shows uml Artifacts deployed on uml Nodes 6 5 1 SapeOne annotations No Sap One annotations are required on the Deployment Diagram 6 5 2 Prima UML annotations The QNM topology is derived from the annotated DD the interacting component instances depicted on the SDs as uml Lifelines are deployed by means of uml Artifacts see Figure 12 on a node equipped with a suitable set of hardware resources Such hardware resources are shown on the deployment diagram in Figure 14 27 Client lt lt PAreso
16. ateStatus PAdemand Cassm mean 0 2 sec Rea lt lt PAstep gt gt ReadStatus ReadStatus PAdemand assm mean 0 2 sec der Brows lt lt PAhost gt CartServer F PAschdPolicy FIFO jus_1 lt lt PAstep gt UpdateStatus_1 Updatestatus_1 PAdemand Cassmn mean 0 3 sec lt lt component gt gt sl lt lt PAstep gt ReadStatus_ ReadStatus_1 PAdemand assm mean 0 2 sec 5 CustomerProcess Updatestatus 4 O eee mean OA OO lt lt PAstep gt FlaceOrder PAdelay mean DI esBaAsten gt gt sBrowseCateoaQ Adela esPAstep gt gt sDeletaemO Pdeiay 0 lt lt PAstep tinsertttem PAdelay Cason lt lt PAstep gt gt DeliveryOrder PAdelay assm mean 0 8 ms Q g an der Deleteltem BrowseCatalog Insertitem Detivervorder lt lt PAhost gt gt CustomerServer PAschdPolicy FIFO lt lt PAstep gt Readinfo PAdemand assm mean 0 2 5e0 lt lt PAstep gt gt tupdateStatus20 PAdemand Cassi mean 0 35 See Dal 18 Note that the exporting of MagicDraw models is not performed starting from the picture that you see in the main editor of Magic Draw but starting from the UML2 tree on the left side of the tool screenshot shown in the next figure You must be sure that the diagram is aligned with the tree so you are sure that what do y
17. atus_1 gt lt Server gt lt Server Name CustomerServer Quantity 1 gt lt Queue Capacity Infinite Name ReadInfo gt lt Queue Capacity Infinite Name updateStatus2 gt lt Server gt lt Server Name CustomerProcess Quantity 1 gt lt Queue Capacity Zero Name BrowseCart gt lt Queue Capacity Zero Name PlaceOrder gt lt Queue Capacity Zero Name BrowseCatalog gt lt Queue Capacity Zero Name Deleteltem gt lt Queue Capacity Zero Name InsertItem gt lt Queue Capacity Zero Name DeliveryOrder gt lt Queue Capacity Zero Name InternalActions gt lt Server gt lt iil lt Figure 6 Mosquito output model xml based notation for SapOne QN model The picture below shows the use of MOSQUITO tool in a performance analysis process The light orange shaded area contains the step under development The entire process starts with the construction of an UML model using any UML tool exporting in Eclipse UML 2 The two methodologies available in MOSQUITO i e SAP one and Prima UML use different sets of diagrams to model the software system Along the SAPone methodology path a QN model is created that represents the system at the software architectural level and can be solved to obtain performance measures at the software level Along the Prima UML methodology path two intermediate models are created i e an EG and a QN that need to be merged to produce a parameterized QN The latter
18. considered The focus is on the customer view by considering only the software system functionalities reported on the figure The choice has been driven by the fact that the focus is on performance aspects hence the customers are the system actors producing more workload to the system Thus the use cases critical from performance perspective are those accessed from them 6 2 1 Sap One annotations No Sap One annotations are required on the Use Case Diagram 6 2 2 Prima UML annotations Prima UML annotates and makes use of the Use Case Diagram UCD to take into account the operational profile The UCD must be annotated with information regarding the probability of a user to access the system as well as the probabilities to invoke different use cases This information is introduced with the stereotype REuser associated to an Actor and on the Actor Use Case association respectively through the ReAccessProb and ReService tags The probabilities of the Use Case Diagram will be used to partially parameterize the performance model Stereotype Syntax Apply Stereotype on Semantic UML metaclasses lt lt REuser gt gt It denotes the probability On the uml Actor that an user accesses the REaccessprob value system It denotes the probability that a provided system functionality can be accessed by all possible users lt lt REservice gt gt On the uml UseCase REprob value lt lt REserviceUsage gt gt It
19. daleSiatus Update Satus demand Casen mean 0 25ec es Pd Saus Radau Ri demand md mear 02 30 A halo ca a Caribe LE A PAschdPalicy FFT Red Status eps Upa Save ae mean s0 sec Ri eps ReadSalus_ f RedSa A fara n 1 3 If the component is an active one then it must have a PAhost stereotype with the scheduling policy field initialized The possible values that this field can assume are FCFS IS PS BAS 4 Every operation must have a PAstep stereotype with PAdemand or PAdelay tag initialized respectively if the component is an active or a passive one Here below we can see an example of Component Diagram created with MagicDraw that is MOSQUITO1 5 compliant package 002 Software Architecture CDs Bf Component Diagram lt lt PAhost gt a OrderServer PAschdPolicy FIFO lt PAstep gt ReadStatus2 ReadStatus2 PAdemand Casen mean 0 2 sec lt lt PAstep NewOrder NewOrder PAdemand Cassm mean 0 1 sec A UpdateStatus lt lt PAhost gt gt Ei DeliveryOrderProcess PAschdPolicy FIFO lt PAhost gt lt lt PAstep gt gt ReadStatus3 PAdemand asstn mean 01 sec CatalogServer Cassmmean 0 18 sec PAschdPolicy FIFO lt lt PAstep gt gt UpdateStatus Upd
20. denotes the probability for On the uml Association between the user to invoke a particular REserviceprob value lt lt REuser gt gt and lt lt REservice gt gt Use case Table 1 Prima UML Stereotypes used on UCD 6 2 2 1 Assumptions 1 Each actor must to be stereotyped with the lt lt REaccessprob gt gt stereotype that allows to specify the probability of the actor to access at the system functionality This value must fall between zero and one UML SPT profile doesn t provide stereotypes to model the operational profile on the Use Case Diagram We extend UML SPT with the lt lt REuser gt gt stereotype Its name comes from another profile introduced for reliability purposes 13 2 Each actor use case connection must be stereotyped with the lt lt REserviceUsage gt gt stereotype that indicates the probability to access to the related use case This value must fall between zero and one as shown in the following figure Dea la insertitem lt ssinclude gt gt lt lt include gt Pan REserviceprob 0 1 sREs rviceUsage gt gt serviceprob 0 2 2 _s lt REseviceUsage gt REserviceproh 0 2 Customer Placeorder gt mE REaccessprob 0 5 serviceprob 0 1 lt lt REuser gt ae lt lt REserviceUsages gt REserviceprob 0 2 EE DeliveryOrder lt REserviceUsage gt cl
21. ed languages and technologies to use the services of MOSQUITO server placed at di univaq it domain The figure here below shows the flow of requests with the Soap protocol to the Axis s APIs that are able to expose the registered services at high level SOAP Input Envelope Apache Web Server Figure 4 Mosquito Web Service architecture The MOSQUITO client that we provide is an Eclipse Plugin that allows an entirely automated process The user must only properly create and annotate UML models according to the selected methodology i e SAP one or Prima UML The extension point used for the MOSQUITO interface is the Eclipse popup menu After the creation of a model the user must only select the UML files uml and activate the desired transformation as shown in the following figure Java EE Eclipse Platform File Edit Refactor Navigate Search Project New gt E HOi 09 RR Open F3 Project Explorer PANN ES Copy Ctrl C E gt Mosquito 1 5 f Paste Ctrl S E src XX Delete Delete JRE System Library jre1 5 0_12 Move Plug in Dependencies Rename F2 bin amp META INF Import model Export ECommerceSystem Refresh FS BY ECommerceSystem mdzip E ECommerceSystem mdzip bak Validate EN E CommerceSystem uml fl Mark as Landmark Ctri Alt Shift Up a MA EEA Remove from Context Ctrl Alt Shift Down oe MA MA el Rename M
22. equence Diagram where the used tag values are PApopulation i e number of user and PAextDelay i e required time to execute a request Possible alternative behaviors in the UML interaction fragments are annotated with the lt lt PAstep gt gt stereotype The PAprob tag value specifies the execution probability of each behavior 6 4 1 1 Assumptions 1 Every Instance of the Sequence Diagram with the exception of the actor must be bound to the associated component as it is shown in the next picture This is necessary to bind the behavioural system specification at the structural one Lifeline lt gt Bi e History 002 Software Architecture CDs CustomerProcess 001 Use Cases y S 002 Software Architecture CDs C a Documentation Hyperlinks Inner Elements Relations E Tags Constraints Applied Stereotype Represents O 002 Software Architecture CDs C To Do 22 2 Every message in the Sequence diagram must be a Call message For every created Call Message you must specify a Return message This entails that the number of Call Messages in the diagram is always the same as the Return Messages E MagicDraw UML 14 0 ECommerceSystem mdzip C Documents and SettingsiFabio CalvareseWesktop MOSQUITO 1 4 ModellisECommerceSystem2 DER File Edit View Layout Diagrams Options Tools Analyze IES Eos haa 001 Use Cases and Scenari
23. erates a sw hw performance model In particular an Use Case Diagram is used to obtain the system usage profile the Sequence Diagrams for the Execution Graph generation and the Deployment Diagram for the EQNM topology generation 10 6 MOSQUITO at work In this section we explain how to introduce the SAP One and Prima UML annotations in the Eclipse UML models The presentation is driven by the eCommerce System example 6 1 eCommerce System Specification In the electronic commerce system there is a supplier that publishes his catalogue on the web The catalogue can be visioned by registered and unregistered users Registered users become customers for the supplier The supplier accepts customer orders and delivers the ordered items maintaining all the relevant data He needs to maintain information on data on the catalogue and on the orders purchased by his customers Each registered customer has a cart where he she can insert or delete items The customer can order only if the cart is not empty The system also allows the customer to monitor the order status and to confirm the delivery in order to permit the payment _ 3 d Order Bir i gt gt DB z Le caros DB CustomerProcesse_ WE AA n AA rey at gt 2 lai aaa DeliveryOrder Process 9 AN LI e Y 2 Fis 7 d ral SupplierProcess _ InvoiceProcess mm lt Bank _DB Figure 8 Overview of the e
24. esource and it must be stereotyped with the lt lt PAresource gt gt stereotype as showed in the picture here below lt PAresource DELAY PAaxTime msr mean 30 sec 30 7 References 1 A Di Marco P Inverardi Compositional generation of Software Architecture Performance ON Models Proc 4th Working IEEE IFIP Conference on Software Architecture WICSA 04 2004 2 V Cortellessa R Mirandola PRIMA UML a Performance Validation Incremental Methodology on Early UML Diagrams Science of Computer Programming 44 2002 no 1 pagg 101 129 3 OMG UML Profile for Schedulability Performance and Time Version 1 1 formal 05 01 02 4 C Smith Performance Solutions Addison Wesley 2002 31 8 Appendix In this appendix we report details of the methodology mechanisms 8 1 Queuing Network process creation SAP one methodology The creation process of the queuing network through the Sap one methodology can be summarized in two steps Identification of the service centers and their carachteristics A delay or waiting service center is associated to every component of the Component Diagram An offered service that corresponds in practice to every interface of the component indicates what job classes are managed by each server Service center characteristics e g time service kind of center and scheduling policy are defined from the associated tag values Classes chain and w
25. fied as a node named TERMINAL This kind of node must be stereotyped with a lt lt PAresource gt gt stereotype that indicates the multiplicity of the hw resource It must be allocated in a deploy node where at least the CPU resource is allocated Here below you can find an example 29 lt PAresource gt TERMINAL PAmultiplicity 100 2 The CPU resource must be specified as a node named CPU This kind of resource is an active resource and it must be stereotyped with the lt lt PAhost gt gt stereotype to indicate the multiplicity the rate and the scheduling policy used from this resource In a model can be used more than one CPU in different deploy nodes The CPU resource is displayed here below lt lt PAhost gt gt CPU PAmultiplicity 1 PArate msr mean 30 sec PAschdPolicy FIFO 3 The DISK resource must be specified as a node named DISK This kind of resources can be active or passive so it can be stereotyped with lt lt PAhost gt gt or lt lt PAresource gt gt It can be used in a deploy node where CPU and TERMINAL resources exist Here below a DISK resource lt PAresource gt gt DISK PAmultiplicity 1 4 The DELAY resource can be specified as a node however named for example LAN WAN DELAY and it represents a resource that introduces a delay in the communication between nodes of the Deployment Diagram It must be allocated in a node with no other r
26. form independent has to be made of a Component Diagram and a set of Sequence Diagrams under the following constraints 1 Each component must have the following structure 16 lt lt PAhost gt SEE CatalogServer PAschdPolicy FIFO lt PAstep gt gt UpdateStatus UpdateStatus PAdemand mean 0 2 sec lt lt PAstep gt gt ReadStatus ReadStatus PAdemand assm mean 0 2 sec In particular for each provided interface you must specify a component operation that returns the interface itself The screenshot here below show this setting for an UpdateStatus operation DI Operation UpdateStatus AR e gt History O UpdateStatus 002 Software Architecture CDs UpdateStatus 00 y MASA a UpdateStatus Documentation Hyperlinks Parameters te di B By Properties Standard Y Template Parameters Relations 4 Tags Constraints E Operation Name UpdateStatus Owner CatalogServer 002 Software Architect Applied Stereotype PAstep Action Message Operation Sta visibility public Method Is Abstract O false Is Static false To Do 2 It is not possible to use the same interface in more than one component This can cause a semantic error during the transformation i ERROR aahh hagis gt Catalog Server FAschdFdicy ec sleps Up
27. hardware resources such as disks or processors rather they represent the software components of the system architecture The UML model represents therefore a platform independent model and the performance indices that can be obtained are somehow parametric This is because the assumption underlying the methodology is that every software component will be placed on a logical device and that all the devices will have the same speed but they can manage requests through queues of different capacity and different scheduling policy In practice the SAP one analysis is comparative in that the obtained performance values are useful to reveal bad architectural choices but they are of little value as absolute performance indices 5 The Prima UML methodology Prima UML 2 is a methodology for the performance modelling of a hw sw model This methodology allows the generation from UML of two models that are 1 a software performance model represented as Execution Graph EG 11 a platform performance model represented as an Extended Queuing Network Model EQNM The merging of the EG and the EQNM models gives rise to a parameterized EQNM that ends the model generation phase This type of system analysis is better suited when the developers have already some ideas on the potential target platforms in that QN server centers in Prima UML represent hw resources The Prima UML methodology starting from properly annotated UML2 diagrams gen
28. i 6 3 Component Diagram In Figure 10 we present the UML 2 0 Component Diagram CD for the portion of the e commerce system we consider This diagram highlights the software components and their required and provided interfaces The provided interfaces are represented by a circle whereas the required ones are represented by a semicircle In general an interface is composed by a set of operations provided or required by a software component Here to simplify the presentation of the parameterization phase we assume that an uml Interface represents uml Operation of the uml Component Then each uml Operation is annotated according to the UML SPT profile in order to introduce performance aspects of software components All the values for the execution times of the uml Operation are assumed see the assm keyword in the tag value as our intent is to carry on a performance analysis at the software architecture level when such information is not available whereas it can be guessed by the designers on the basis of their experience or on the basis of previous releases of the same software system Note that we extend the lt lt PAstep gt gt stereotype with the Operation metaclass in order to allow the annotation of the component Operation 14 lt lt PAhost gt gt a OrderServer PAschdPolicy FIFO lt lt PAstep gt gt newOrder PAdemand assm mean 0 1 s lt lt PAstep gt gt readStatus PAdemand
29. lt lt peoqpasojjyd a A aai Qbeusepsgeoeid 19AJ95A19UIOJSNI S9 lt lt 150 gt E 19AJ9SADPAO SO lt lt S0Uwd gt gt E 53904J13p10 M43A1190 dop lt lt JS0YYd gt gt 19AJSGHLI 5 lt lt JS0UYd gt gt sse201qseuiojsng do lt lt Js0UYd gt gt 015 19 lt lt sOUWd gt gt 4eulo3sng SY lt lt lasn3y gt gt iagram the Sequence D Figure 11 21 6 4 1 Sap One annotations The Sequence Diagram SD must be enriched with the information in the following table Stereotype Syntax Apply Stereotype on Semantic UML metaclasses lt lt PAclosedLoad gt gt This stereotype denotes the closed workload of the PApopulation population On the first uml Message of the scenario depicted on the quantity Sequence Diagram Sequence Diagram in PAextDelay assm mean particular its population and 30 ms the think time lt lt PAstep gt gt It denotes the probability to PAprob uo On the first uml Message used on da Le prob value i i me es T With probability 1 value the i e ifand then operands ofthe control is given to the first Alt uml CombinedFragment message following the alt compartment Table 3 SapeOne Stereotypes used on SD The stereotype PAclosedLoad specifies the closed workload intensity and it is used to annotate the first message of every S
30. odel E oe UML_Profile_for_Schedulabilty _Pe da UML_Profile_for_Schedulabilty _Per PSN UML_Profile_for_Schedulabilty _ Per de UML_Profile_for_Schedulabilty _Per amp de UML_Profile_for_Schedulabilty _Per EB UML_Standard_Profile MagicDraw_ PSN UML_Standard_Profile MagicDraw_f Se UML_Standard_Profile UML_Standa da UML_Standard_Profile Validation_PW Debug As Profile As Team Compare With Replace With Code Generator Topcased Traceability Source 7 OSATE 3 me Sa 12 items selected Properties Alt Enter gt gt gt MOSQUITO Open As Figure 5 Invoking Mosquito transformations from Eclipse Platform The result of the transformation will be showed in the Eclipse XML editor as follows eventually a WARNING or ERROR tabs will be displayed containing the warnings or errors about input model respectively 3 PRIMAUML_EG xml 9 PRIMAUML_QN xml m lt xml version 1 0 encoding ASCII gt Aa lt QueueingNetworkModel xmins xsi http www w3 org 2001 XMLSchema instance xsi noNamespaceSchemaLoc lt Node gt lt Server Name CatalogServer Quantity 1 gt lt Queue Capacity Infinite Name UpdateStatus gt lt Queue Capacity Infinite Name ReadStatus gt lt Server gt lt Server Name CartServer Quantity 1 gt lt Queue Capacity Infinite Name UpdateStatus_1 gt lt Queue Capacity Infinite Name ReadSt
31. on such as subsystem or component instances objects and so on and how they interacts each other to accomplish a task In the UML terminology interactions are units of behavior that focus on the observable exchange of information between elements such as objects in form of messages UML 2 0 defines four different interaction diagrams sequence diagram communication diagram interaction overview 19 diagram and timing diagram Among these diagrams both SapeOne and PRIMAUML methodologies use Sequence Diagrams they specify messages that are exchanged between component instances whose types are depicted on Component Diagram that are in charge to provide the system functionalities i e the use cases depicted on Use Case Diagram As example scenario the PlaceOrder sequence diagram is presented in Figure 11 The Sequence Diagram is composed by several nested combined fragments and their operands In particular it shows an example of two alternative behaviors specified by means of an alt operator with two InteractionOperand A Customer asks for an order placing through his own Customerlnterface and first of all the CustomerProcess reads the cart status on the CartServer If the cart is empty the order cannot be placed see the second interaction operand in the alt combined fragment Otherwise the CustomerProcess proceeds in collecting the customer information such as for example his mail address and creates a new order in the Order DB Finally i
32. orkload definition The Sequence Diagrams with the annotated information represent the workload intensity while the net topology is defined analysing the dynamics of communication between components The idea is to associate a connection in the queuing network from each sender component i e a component that sends a messages in some Sequence Diagrams to each receiving component The receiving component will have infinite queue if the interaction is asynchronous whereas a null queue if synchronous SAP one defines a set of translation rules combined to various architectural patterns corresponding to at interaction fragment of UML Sequence Diagrams In this way it is possible to generate the complete architectural topology stepwise while parsing the UML diagrams 1 8 2 Execution Graph creation Prima UML methodology The translation rules used from the Prima UML methodology can be summarized in the following steps Estimation of scenarios execution probability In Figure 15 an annotated UCD is shown users and arcs are annotated with weights that lead to compute the probability that each use case is expected to occur Note that early in the lifecycle these weights come out from designer s guesses on the operational profile whereas later they can be obtained from actual measures 32 usecase 1 gt AN M p user j na PW y Coons usecase user 1 p 1 AA EA Mm Pa lt use case i p E u
33. os UCDs and Relations Customer lt O BrowseCart con lt gt browseCatalog Deleteltem DeliveryOrder gt InsertItem 4 lt gt PlaceOrder EN ECS Use Case Diagram 002 Software Architecture CDs 7 Relations O BrowseCart O BrowseCatalog CreateNewOrder PlaceOrder CustomerProcess CartServer Hi Insertttem J CustomerProcess S SME z 1 Insertitem er lt lt PAclosedLoad gt gt lt lt PAhost gt gt a CartServer 1 message 2 UpdateStatus_1 PAextDelay assm PApopulation 200 4 ean 20 ms g 3 Every Call Message must have the property operation initialized with the name of the operation to invoke in the receiving component Next picture show this setting for the CallMessage that invokes the InsertItem operation 5 Documentation Hyperlinks 3 Arguments 5 Conveyed Information 5 Inner Elements Relations dj Tags dj Constraints lt gt 4 Call Message InsertItem 001 Use Cases and Scenarios UCDs and SD E s sori E Message Operation Signature Owner Applied Stereotype Message Type Send Event Receive Event Message Sort To Do O Insertltem 002 E InsertItem 001 Use C lt PAclosedLoad Action Mess Call Message synchCall Properties Standard v g tware
34. ou see in the graphics is what MOSQUITO will process PlaceOrder i I ECS Use Case Diagram BH 002 Software Architecture CDs i Relations CreateNewOrder Deleteltem O UpdateStatus2 O Updatestatus_1 4 4 CartServer lt lt PAhost gt gt 1 8 CatalogServer lt lt PAhost gt gt CustomerProcess CustomerServer lt lt PAhost gt gt 4 DeliveryOrderProcess lt lt PAhost gt gt 4 5 OrderServer lt lt PAhost gt gt a CatalogServer a Customer Interface a Customer Process Skeleton a CustomerProcess Stub a CustomerServer EA DeliveryOrderProcess Deployable Artifacts ykgCOMponent Diagram 6 3 2 Prima UML annotations No Prima UML annotations are required on the Component Diagram 6 4 Sequence Diagram Interaction diagrams are a common mechanism for describing systems at varying levels of detail in a way comprehensible by both software designers and potential end users and stakeholders of the system Typically the interaction diagrams do not describe the whole system behavior but selected execution traces There are normally other legal and possible interactions that are not contained within the drawn diagrams Originally interaction diagrams represent system objects and how they interact In the new conception UML 2 0 such diagrams describe the system by means of participants that can be system modules at a different level of abstracti
35. ponent is not extended then it corresponds to a delay resource without queue and with an infinite number of lt lt PAhost gt gt On the uml Component PAschdPolicy type instances lt lt PAstep gt gt On the component The execution time to satisfy PAdemand uml Operation implementing each services request assm mean value unit time the homonymous provided PAdemand must to be used for uml Interface active components whereas XOR PAdelay must be used for passive ones PAdemand and PAdelay PAdelay tags are mutually assm mean value unit time exclusive because a component can t be active and passive at the same time Table 2 Sap One Stereotypes used on CD Each software component is annotated with the lt lt PAhost gt gt stereotype and the methodology works under the hypothesis that every component is allocated on a different active resource The tag value PAschdPolicy denotes the scheduling policy of the component queue The PAstep stereotype is associated to the component operation implementing the homonymous interface both tag values PAdemand for active components and PAdelay for passive components model the component execution time to satisfy a request exposed by the interface In particular the syntax to use within the CD is summarized in Table 2 6 3 1 1 Assumptions Likewise to the previous versions of MOSQUITO the input model for building a QN plat
36. rch for New features to Install 2 3 Installing MOSQUITO You can download MOSQUITO client from the following web page http sealabTools di univag it SeaLab MosquitoDownload html MOSQUITO is a plugin of the Eclipse platform and its installation like every other Eclipse plugin is very simple It is sufficient to unzip the zip file di univaq MOSQUITO in the main folder of Eclipse e g c eclipse After this step verify if the plugin jar file appears in the plugin directory e g c eclipse plugins di univaq MOSQUITO_1 5 0 jar and you must be sure that previously installed MOSQUITO versions have been removed from the system Eclipse caches plug in information in a configuration directory For this reason the first launching of Eclipse with the installed MOSQUITO plugin must be performed using the clean command line option so that the cached plugin in information will be rebuilt To do this you must use the prompt to launch Eclipse If you are in the directory of Eclipse installation them you must type the Eclipse clean command as reported in picture here below e Prompt dei comandi BO Microsoft Windows amp P Versione 5 1 2600 CC Copyright 1985 2001 Microsoft Corp C Documents and Settings Fabio Calvarese gt cd ADocuments and Settings gt cd gt ed Programmi AProgrammi gt cd eclipse Programmiteclips gt eclipse clean_ Figure 2 Eclipse refresh procedure After started the Eclipse platfo
37. rm you can verify the correct MOSQUITO installation by inspecting the plug in details under Help gt About Eclipse SDK gt Plug in Detail The MOSQUITO plugin must appear in the list of the currently installed plugins 3 MOSQUITO at a glance MOSQUITO MOdel driven conStruction of QUeuIng neTwOrks is a tool that generates Queueing Network models from UML software models according to the SAP one 1 and the Prima UML 2 methodologies MOSQUITO allows to annotate UML software models with performance data and finally creates an XML representation of performance models MOSQUITO in its current release can create three different models that are 1 Queuing Networks based on the SAP one methodology 11 Execution Graphs based on the first part of the Prima UML methodology 111 Queueing Networks based on the Prima UML methodology MOSQUITO has a client server architecture The plugin di univaq MOSQUITO implements the client side that provides the functionality to invoke the web services placed at the University of L Aquila The system architecture is shown here below Result IT 5 Request of transformation Eclipse MOSQUITO plugin Server Odi univaq it on the client machine Figure 3 Mosquito client server architecture In particular MOSQUITO is exposed as a web service This will allow in next MOSQUITO releases any user to implement an alternative client using the preferr
38. rt Export API code and its textual description Eclipse UML uses the official OMG UML 2 1 Superstructure specification to define its own API 11 For the sake of presentation a simplified version of this system is considered The focus is on a subset of customer functionalities In particular only catalogue browsing cart browsing item insertion and deletion to from the cart order placement functionalities will be considered 6 2 Use Case Diagram Figure 9 shows the use case diagram UCD for the e commerce system Three actors are in the system Customer Supplier and Bank The e commerce customer can browse both the cart BrowseCart and the catalogue BrowseCatalog she he can insert and delete items to from the cart Insertltem and Deleteltem respectively She He can place an order and check its status PlaceOrder and BrowseOrderStatus and finally she he can confirm the delivery ConfirmDelivery of the items ordered The use case diagram also specifies that both Insertltem and Deleteltem functionalities use the BrowseCart in their execution lt lt extend gt ssextend gt gt _ 7 Pali i ages REservigeUsage gt gt sage gt lt lt REservice gt REserviceptob 0 1 REsemvicepfob 0 2 Delete Item from Catalogue REprob 0 05 lt lt REserviceUsage gt REserviceprob 0 3 lt lt REuser gt Customer REaccessprob 0 7 lt lt REserviceUsage gt gt
39. st gt gt a CustomerServer PAschdPolicy FIFO readinfo lt lt PAstep gt gt tupdateStatus PAdemand assm mean 0 3 s _ PAstep gt gt readinfo PAdemand assm mean 0 2 8 4 5 updateStatus lt lt component gt Customerinterface gt z P Astep gt browseCartReq PAdemand assm mean 0 889 placeOrderReq lt PAstep gt gt placeOrderReg PAdemand assm mean 0 8 8 lt lt PAstep gt insertitemReg PAdemand assm mean 0 8 s lt lt PAstep gt gt deletelttemReq PAdemand assm mean 0 8 s browseCartReq lt lt PAstep gt browseCatalogReq PAdemand assm mean 0 8 s i gt browseCatalogReq deleteltemReq InsertitemReq Figure 10 Component Diagram The considered sub system is composed by six components Four of them OrderServer CatalogServer CartServer CustomerServer interact with the corresponding databases by easying the insertion deletion reading and updating of data These components allow asynchronous communications hence all the interfaces they provide contain asynchronous operations The remaining three components namely Customerlnterface CustomerProcess and DeliveryOrderProcess provide the GUI to interact with the system the back end process that manages all her his request as made through the GUI and the business process
40. t empties the customer cart In this scenario it is assumed that all the information the customer must provide to place an order is collected before and the PlaceOrder request corresponds to the final submission from the customer Moreover the payment procedure is encompassed in a different use case For example if the customer decided to pay by a credit card the Payment amp Invoice use case see Figure 9 will be in charge to manage the bank transfer 20 n 4 beoz q gt 8 6 0 uBaw wsse Aeja r a0 re dia ds yeBed ueo Mgdua 9L r eondu ST gt gua peo o ee jos e e See po e y e ES po 2 2 PS Ra ii Sul 18 A i gt Ns aBediapio L NON lic Ao i pasosu JB LUOISNO y AD 2 lt l Qsnyzeqgezepdn pp bad S OJULSPIO OL a s 70 u aw wsse puewapyd gt a i lt lt dalsyd gt gt OJULSPIO 6 pasau Japo uepsomeu 8 23 oju 615 9 T ae E lt 5 _ 0000 h lii i UP i E ae 1 N Oojuipees G i 80 a01dva y B pasosu gq Jawosno qa HA HED dwa you eo 1 b b 1 pa Le A J l snye3speal e y e 4epsgeoeld z ooz uoneindolly l st 00 ueaw wsse Aejeapaya j
41. to manage the order delivery respectively These components interact asynchronously with the DB servers and synchronously among them Thus the interfaces they provide respect such properties Finally since the component diagram in the figure only describes the portion of the e commerce system considered it does not contains the components and the interfaces that are not involved in the use cases considered For example the component that allows the Supplier to delete or insert an item in the catalogue is missing as well as the corresponding CatalogServer provided interfaces that manage such operations on the corresponding database 15 CustomerProcess and CustomerInterface are components running at the user side There are instances of them dedicated to each user logged in the system This design choice makes the CustomerProcess and CustomerInterface components unshared resources i e passive components and hence their execution times constitute delays 6 3 1 Sap One annotations The Component Diagram CD is annotated with parameters related to the components as each component is transformed into a Queueing Network server center Example paramters are the kind of center i e waiting or delay and the scheduling policy that it uses to extract requests from its queue e g FIFO IS etc Stereotype Syntax Apply Stereotype on Semantic UML metaclasses If a component is extended with this stereotype its queue has a type If a com
42. urce gt gt lt lt PAhost gt lt PAresource gt gt TERMINAL CPU DISK PAmultiplicity 100 PAmultiplicity 1 PAmultiplicity 1 PArate msr mean 30 sec Network lt PAresource gt gt DELAY PAaxTime msr mean 30 sec ssP amp Ahost gt CPU PAmultiplicity 2 PArate msr mean 30 sec PAschdPolicy FIFO lt PAresource gt gt DISK PAmultiplicity 4 Figure 14 Annotated Deployment Diagram for the Prima UML methodology Hardware resources are distinguished in active and passive ones by means the lt lt PAhost gt gt and lt lt PAresource gt gt stereotypes respectively 3 The Prima UML methodology makes use of three different kind of resources over a uml Node e CPU as the name itself suggests is a active lt lt PAhost gt gt resource representing CPUs e DISK that represents a storage passive lt lt PAresource gt gt resource e TERMINAL that represents users jobs that access the container node 4 A processing resource i e PAhost is a device which has processing steps allocated to it A passive resource i e PAresource represents a resource protected by an access mechanism e g a semaphore which is accessed during the execution of an operation gt CPU DISK and TERMINAL are reserved words 28 Table 5 specifies the additional information that has to be specified for such kind of resources Stereotype Syntax Apply Stereotype
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