Object Oriented Methodologies - Sushant's Technical Articles
Object Oriented MethodologiesChapter 4Sahaj Computer SolutionsObject Oriented Systems Development1
Chapter Objectives Object Oriented Methodologies The Rumbaugh et al. OMT The Booch Methodology Jacobson’s MethodologiesPatterns Frameworks Unified Approach Sahaj Computer SolutionsObject Oriented Systems Development2
Introduction In the 1980s , many methodologies weredeveloped. 1986. Booch developed the object orienteddesign concept, the Booch Method. 1987. Sally Shlaer and Steve Mellor createdthe concept of the recursive design. 1989. Beck and Cunningham produced classresponsibility- collaboration cards. 1990. Wrifts-Brock, Wilkerson, and Wienercame up with responsibility driven design.Sahaj Computer SolutionsObject Oriented Systems Development3
Introduction 1991. Jim Rumbaugh led a team at theresearch labs of General Electric to developthe object modeling technique(OMT). 1991. Peter Coad and Ed Yourdon developedCoad lightweight and prototype-orientedapproach to methods. 1994. Ivar Jacobson introduced the concept ofthe use case and object oriented softwareengineering(OOSE)Sahaj Computer SolutionsObject Oriented Systems Development4
Rumbaugh et al.’s Object ModelingTechniqueThe object modeling technique(OMT)presented by Jim Rumbaugh and his coworkers describes a method for analysis,design, and implementation of a systemusing an object –oriented technique. OMT is a fast and intuitive approach foridentifying and modeling all the objectsmaking up a system. Sahaj Computer SolutionsObject Oriented Systems Development5
Rumbaugh et al.’s Object ModelingTechniqueDetails such as class, attributes, method,inheritance, and association also can beexpressed easily. The dynamic behavior of objects within asystem can be described using OMTdynamic model. Finally a process description , a producerconsumer relationships can be expressedusing OMT’s functional model. Sahaj Computer SolutionsObject Oriented Systems Development6
Rumbaugh et al.’s Object ModelingTechnique OMT consists of four phases, which can beperformed iteratively: Analysis: The results are objects and dynamic andfunctional models. System design: The results are a structure of thebasic architecture of the system along with high–level strategy decisions. Object Design: This phase produces a designdocument, consisting of detailed object static,dynamic and functional models. Implementation: This activity produces reusable,extendible and robust codeSahaj Computer SolutionsObject Oriented Systems Development7
Rumbaugh et al.’s Object ModelingTechnique OMT separates modeling into threedifferent parts: An object model, presented by object modeland the data dictionary. A dynamic model, presented by state diagramand event flow diagrams. A functional model, presented by data flowand constraints.Sahaj Computer SolutionsObject Oriented Systems Development8
The Object ModelThe object model describes the structureof objects in a system: their identity,relationships to other objects, attributesand operations. The object diagram contains classesinterconnected by association lines. Each class represents a set of individualobjects. The association lines establishrelationships among the classes. Sahaj Computer SolutionsObject Oriented Systems Development9
The OMT Dynamic Model OMT provides a detailed and comprehensivedynamic model, in addition to letting youdepict states, transitions, events, and actions.The state transition diagram is a network ofstates and events.Each state receives one or more events, atwhich time it makes the transition to thenext state.The next state depends on the current stateas well as the events.Sahaj Computer SolutionsObject Oriented Systems Development10
The OMT Functional ModelThe OMT data flow diagram(DFD) shows theflow of data between different processes in abusiness. An OMT DFD provides a simple and intuitivemethod for describing business processes withoutfocusing on the details of computer systems Data flow diagram use four primary symbols: The process is any function being performed The data flow shows the direction of the dataelement movement. The data store is a location where data are stored. An external entity is a source or destination of a dataelement.Sahaj Computer SolutionsObject Oriented Systems Development11
The Booch methodology The booch methodology is a widely usedobject-oriented method that helps youdesign your system using the objectparadigm.It covers analysis and design phases of anobject-oriented system.You start with class and object diagram inthe analysis and refine these diagrams invarious steps.Only when you are ready to generate codethe Booch method shines and you candocument your object oriented code.Sahaj Computer SolutionsObject Oriented Systems Development12
The Booch methodology The booch method consists of the followingdiagrams: Class DiagramObject DiagramState transition DiagramModule DiagramsProcess DiagramsInteraction DiagramsThe booch method prescribes a macrodevelopment and a micro developmentprocess.Sahaj Computer SolutionsObject Oriented Systems Development13
The Macro Development ProcessThe macro process serves as a controllingframework for the micro process and cantake weeks or even months. The primary concern of macro process istechnical management of the system. In macro process the traditional phases ofanalysis and design to a large extent arepreserved. The macro development consists of thefollowing steps: Sahaj Computer SolutionsObject Oriented Systems Development14
The Macro Development Process Conceptualization: During Conceptualization , you establish the corerequirements of the system. Establish a set of goals and develop a prototype toprove the concept Analysis and Development of the model: In this step, you use the class diagram to describethe roles and responsibilities objects carry out inperforming the desired behavior of the system. Then, you use the object diagram to describe thedesired behavior of the system in terms ofscenarios, or alternatively use interaction diagrams.Sahaj Computer SolutionsObject Oriented Systems Development15
The Macro Development Process Design or create the system architecture: In the design phase, you use the class diagram todecide what classes exists & how they relate toeach other. Next you use the object diagram to decide whatmechanism are used to regulate how objectcollaborate. Then, you use the module diagram to map outwhere each class and object should be declared. Finally, you use the process diagram to determineto which processor to allocate a process.Sahaj Computer SolutionsObject Oriented Systems Development16
The Macro Development Process Evolution or Implementation Successively refine the system through manyiterations. Produce a stream of software implementations(orexecutable releases), each of which is a refinementof the prior one. Maintenance: Make localized changes to the system to add newrequirements and eliminate bugs.Sahaj Computer SolutionsObject Oriented Systems Development17
The Micro Development process Each macro development process has itsown micro development processes.It is a description of the day to dayactivities by a single or small group ofsoftware developers.The micro development process consists ofthe following steps: Identify classes and objectsIdentify class and object semanticsIdentify class and object relationships.Identify class and object interfaces andimplementation.Sahaj Computer SolutionsObject Oriented Systems Development18
JACOBSON ET AL.METHODOLOGIESThe Jacobson et al. methodologies (e.g., objectoriented Business Engineering (OOBE), objectoriented Software Engineering (OOSE), andObjectory) cover the entire life cycle and stresstraceability between the different phases, bothforward and backward. This traceability enables reuse of analysis anddesign work, possibly much bigger factors in thereduction of development time than reuse ofcode. At the heart of their methodologies is the usecase concept, which evolved with Objectory(Object Factory for Software Development). Sahaj Computer SolutionsObject Oriented Systems Development19
THE JACOBSON ET AL.METHODOLOGIES Use cases Use cases are scenarios for understanding systemrequirements. A use case is an interactionbetween users and a system. The use-case modelcaptures the goal of user and the responsibility ofthe system to its users FIGURE 4-6: Some uses of a library. As you can see, these areexternal views of the library system from anactor such as a member. The simpler the use case,the more effective it will be. It is unwise tocapture all of the details right at the start; you cando that later.Sahaj Computer SolutionsObject Oriented Systems Development20
THE JACOBSON ET AL.METHODOLOGIESSahaj Computer SolutionsObject Oriented Systems Development21
THE JACOBSON ET AL.METHODOLOGIES In the requirements analysis, the useeases, are described as one of thefollowing : Nonformal text with no clear flow of events. Text, easy to read but with a clear flow ofevents to follow (this is a recommendedstyle). Formal style using pseudo code.Sahaj Computer SolutionsObject Oriented Systems Development22
THE JACOBSON ET AL.METHODOLOGIES The use case description must contain: How and when the use case begins and ends. The interaction between the use case and itsactors, including when the interaction occursand what is exchanged. How and when the use case will need datastored in the system or will store data in thesystem. Exceptions to the flow of events. How and when concepts of the problemdomain are handled.Sahaj Computer SolutionsObject Oriented Systems Development23
THE JACOBSON ET AL.METHODOLOGIESUse cases could be viewed as concrete orabstract. An abstract use case is not completeand has no actors that initiate it but isused by another use case. This inheritance could be used in severallevels. Abstract use cases also are the ones thathave uses or extends relationships. Sahaj Computer SolutionsObject Oriented Systems Development24
Object-Oriented SoftwareObjectEngineering: ObjectoryObject-oriented software engineering(OOSE), also called Objectory, is a methodof object-oriented development with thespecific aim to fit the development oflarge, real-time systems. The development process, called use-casedriven development, stresses that use casesare involved in several phases of thedevelopment , including analysis, design,validation, and testing. Sahaj Computer SolutionsObject Oriented Systems Development25
Object-Oriented SoftwareObjectEngineering: Objectory The use-case scenario begins with a user ofthe system initiating a sequence ofinterrelated events.The system development method based onOOSE, Objectory, is a disciplined process forthe industrialized development of software,based on a use-case driven design.It is an approach to object-oriented analysisand design that centers on understandingthe ways in which a system actually is used.Sahaj Computer SolutionsObject Oriented Systems Development26
Object-Oriented SoftwareObjectEngineering: Objectory Objectory is built around several differentmodels: Use case-model. The use-case model defines theoutside (actors) and inside (use case) of the system'sbehavior. Domain object model. The objects of the "real" worldare mapped into the domain object model. Analysis object model. The analysis object modelpresents how the source code (implementation)should be carried out and written. Implementation model. The implementation modelrepresents the implementation of the system. Test model. The test model constitutes the test plans,specifications, and reports.Sahaj Computer SolutionsObject Oriented Systems Development27
Object-Oriented BusinessObjectEngineeringObject-oriented business engineering(OOBE) is object modeling at theenterprise level. Use cases again are the central vehicle formodeling, providing traceabilitythroughout the software engineeringprocesses. Sahaj Computer SolutionsObject Oriented Systems Development28
Object-Oriented BusinessObjectEngineering Analysis phase: The analysis phase defines the system to be built in termsof the problem-domain object model, the requirementsmodel, and the analysis model. The analysis process should not take into account theactual implementation environment. This reduces complexity and promotes maintainabilityover the life of the system, since the description of thesystem will be independent of hardware and softwarerequirements. The analysis process is iterative but the requirements andanalysis models should be stable before moving on tosubsequent models. Jacobson et al. suggest that prototyping with a tool mightbe useful during this phase to help specify user interfaces.Sahaj Computer SolutionsObject Oriented Systems Development29
Object-Oriented BusinessObjectEngineering Design and implementation phases. The implementation environment must beidentified for the design model. This includes factors such as DatabaseManagement System (DBMS), distribution ofprocess, constraints due to the programminglanguage, available component libraries, andincorporation of graphical user interface tools. It may be possible to identify the implementationenvironment concurrently with analysis. The analysis objects are translated into designobjects that fit the current implementationenvironment.Sahaj Computer SolutionsObject Oriented Systems Development30
Object-Oriented BusinessObjectEngineering Testing phase. Finally, Jacobson describes several testinglevels and techniques. The levels include unit testing, integrationtesting, and system testing.Sahaj Computer SolutionsObject Oriented Systems Development31
PatternsAn emerging idea in systems development is thatthe process can be improved significantly if asystem can be analyzed, designed, and built fromprefabricated and predefined system components. One of the first things that any science orengineering discipline must have is a vocabularyfor expressing its concepts and a language forrelating them to each other. Therefore, we need a body of literature to helpsoftwaredevelopersresolvecommonlyencountered, difficult problems and a vocabularyfor communicating insight and experience aboutthese problems and their solutions. Sahaj Computer SolutionsObject Oriented Systems Development32
PatternsThe use of design patterns originates in the workdone by a building architect named ChristopherAlexander during the late 1970s. A Timeless Way of Building ,that, in addition to givingexamples, described his rationale for documentingpatterns. The main idea behind using patterns is to providedocumentation to help categorize andcommunicate about solutions to recurringproblems. The pattern has a name to facilitate discussionand the information it represents. Sahaj Computer SolutionsObject Oriented Systems Development33
Pattern A pattern is [an] instructive informationthat captures the essential structure andinsight of a successful family of provensolutions to a recurring problem that ariseswithin a certain context and system offorces.A pattern involves a general description of asolution to a recurring problem bundle withvarious goals and constraints.But a pattern does more than just identify asolution, it also explains why the solution isneeded.Sahaj Computer SolutionsObject Oriented Systems Development34
Pattern The documentation of a pattern, in essence,provides the contexts under which it issuitable and the constraints and forces thatmay affect a solution or its consequences.Communication about patterns is enabled bya vocabulary that describes the pattern andits related components such as name,context, motivation, and solution.By classifying these components and theirnature (such as the structural or behavioralnature of the solution), we can categorizepatterns.Sahaj Computer SolutionsObject Oriented Systems Development35
Pattern A good pattern will do the following: It solves a problem. Patterns capture solutions,not just abstract principles or strategies. It is a proven concept. Patterns capturesolutions with a track record, not theories orspeculation. The solution is not obvious. The best patternsgenerate a solution to a problem indirectly—anecessary approach for the most difficultproblems of design.Sahaj Computer SolutionsObject Oriented Systems Development36
Pattern It describes a relationship. Patterns do not justdescribe modules, but describe deeper systemstructures and mechanisms. The pattern has a significant human component.All software serves human comfort orquality-of life; the best patterns explicitlyappeal to aesthetics and utility.Sahaj Computer SolutionsObject Oriented Systems Development37
Generative and NongenerativePatternsGenerative patterns are patterns that notonly describe a recurring problem, theycan tell us how to generate somethingand can be observed in the resultingsystem architectures they helped shape. Nongenerative patterns are static andpassive: They describe recurringphenomena without necessarily sayinghow to reproduce them. Sahaj Computer SolutionsObject Oriented Systems Development38
Patterns Template Currently, several different pattern templateshave been defined that eventually willrepresent a pattern.Despite this, it is generally agreed that apattern should contain certain essentialcomponents. Name. A meaningful name. Problem. A statement of the problem thatdescribes its intent Context. The preconditions under which theproblem and its solution seem to re-cur and forwhich the solution is desirable.Sahaj Computer SolutionsObject Oriented Systems Development39
Patterns Template Forces. A description of the relevant forces andconstraints and how they interact or conflict withone another and with the goals we wish toachieve (perhaps with some indication of theirpriorities). Solution. Static relationships and dynamic rulesdescribing how to realize the desired outcome. Examples. One or more sample applications ofthe pattern that illustrate a specific initial context;how the pattern is applied to and transforms thatcontext; and the resulting context left in its wake.Sahaj Computer SolutionsObject Oriented Systems Development40
Patterns Template Resulting context. The state or configuration ofthe system after the pattern has been applied,including the consequences (both good and bad)of applying the pattern, and other problems andpatterns that may arise from the new context. Itdescribes the postconditions and side effects of thepattern. Rationale. A justifying explanation of steps or rulesin the pattern and also of the pattern as a wholein terms of how and why it resolves its forces in aparticular way to be in alignment with desiredgoals, principles, and philosophies.Sahaj Computer SolutionsObject Oriented Systems Development41
Patterns Template Related patterns. The static and dynamicrelationships between this pattern and otherswithin the same pattern language or system. Known uses. The known occurrences of thepattern and its application within existingsystems.Sahaj Computer SolutionsObject Oriented Systems Development42
AntipatternsA pattern represents a "best practice,"whereas an antipattern represents "worstpractice" or a "lesson learned." Antipatterns come in two varieties: Those describing a bad solution to a problemthat resulted in a bad situation. Those describing how to get out of a badsituation and how to proceed from there to agood solution.Sahaj Computer SolutionsObject Oriented Systems Development43
Antipatterns Antipatterns are valuable because often itis just as important to see and understandbad solutions as to see and understandgood ones.Sahaj Computer SolutionsObject Oriented Systems Development44
Capturing Patterns Writing good patterns is very difficult,explains Appleton.Patterns should provide not only facts (like areference manual or users' guide) but alsotell a story that captures the experiencethey are trying to convey.A pattern should help its users comprehendexisting systems, customize systems to fituser needs, and construct new systems.The process of looking for patterns todocument is called pattern mining (orsometimes reverse architecting).Sahaj Computer SolutionsObject Oriented Systems Development45
Capturing Patterns Guidelines are summarized from Buschmann et al.Focus on practicability. Patterns should describe proven solutions to recurringproblems rather than the latest scientific results. Aggressive disregard of originality. Pattern writers do not need to be the original inventor ordiscoverer of the solutions that they document. Nonanonymous review. Pattern submissions are shepherded rather than reviewed.The shepherd contacts the pattern author(s) and discusseswith him or her how the patterns might be clarified orimproved on.Sahaj Computer SolutionsObject Oriented Systems Development46
Capturing Patterns Writer’s workshops instead of presentations. Rather than being presented by the individualauthors, the patterns are discussed in writers'workshops, open forums where all attending seekto improve the patterns presented by discussingwhat they like about them and the areas in whichthey are lacking. Careful editing. The pattern authors should have the opportunityto incorporate all the comments and insightsduring the shepherding and writers' workshopsbefore presenting the patterns in their finishedform.Sahaj Computer SolutionsObject Oriented Systems Development47
FrameworksA framework is a way of presenting a genericsolution to a problem that can be applied to alllevels in a development .However, design andsoftware frameworks are the most popular. Adefinition of an object-oriented softwareframework is given by Gamma et al: A framework is a set of cooperating classes thatmake up a reusable design for a specific class ofsoftware. A framework provides architectural guidance bypartitioning the design into abstract classes anddefining their responsibilities and collaborations. Sahaj Computer SolutionsObject Oriented Systems Development48
Frameworks A developer customizes a framework to aparticular application by subclassing andcomposing instances of framework classes.The framework captures the designdecisions that are common to its applicationdomain. Frameworks thus emphasize designreuse over code reuse, though a frameworkwill usually include concrete subclasses youcan put to work immediately.Sahaj Computer SolutionsObject Oriented Systems Development49
Frameworks Gamma et al. describe the major differencesbetween design patterns and frameworks asfollows:Design patterns are more abstract thanframeworks. Frameworks can be embodied in code, but onlyexamples of patterns can be embodied in code. A strength of frameworks is that they can bewritten down in programming languages and notonly studied but executed and reused directly.Sahaj Computer SolutionsObject Oriented Systems Development50
Frameworks Design patterns are smaller architecturalelements than frameworks. A typical framework contains several designpatterns but the reverse is never true. Design patterns are less specialized thanframeworks. Frameworks always have a particular applicationdomain. In contrast, design patterns can be usedin nearly any kind of application. While more specialized design patterns arecertainly possible, even these would not dictatean application architecture.Sahaj Computer SolutionsObject Oriented Systems Development51
The Unified ApproachThe unified approach (UA) establishes a unifyingand unitary framework around their works byutilizing the unified modeling language (UML) todescribe, model, and document the softwaredevelopment process. The idea behind the UA is not to introduce yetanother methodology. The main motivation here is to combine the bestpractices, processes, methodologies, andguidelines along with UML notations and diagramsfor better understanding object-orientedconcepts and system development. Sahaj Computer SolutionsObject Oriented Systems Development52
The Unified Approach The unified approach to softwaredevelopment revolves around (but is notlimited to) the following processes andconcepts :The processes are: Use-case driven developmentObject-oriented analysisObject-oriented designIncremental development and prototypingContinuous testingSahaj Computer SolutionsObject Oriented Systems Development53
The Unified Approach The methods and technology employedinclude Unified modeling language used for modeling. Layered approach. Repository for object-oriented systemdevelopment patterns and frameworks. Component-based development (Although,UA promote component-based development,the treatment of the subject is beyond thescope of the book.)Sahaj Computer SolutionsObject Oriented Systems Development54
The Unified ApproachThe UA allows iterative development byallowing you to go back and forthbetween the design and the modeling oranalysis phases. It makes backtracking very easy anddeparts from the linear waterfall process,which allows no form of backtracking. Sahaj Computer SolutionsObject Oriented Systems Development55
Object--Oriented AnalysisObjectAnalysis is the process of extracting theneeds of a system and what the systemmust do to satisfy the users'requirements. The goal of object-oriented analysis is tofirst understand the domain of theproblem and the system's responsibilitiesby understanding how the users use orwill use the system. Sahaj Computer SolutionsObject Oriented Systems Development56
Object--Oriented AnalysisObjectOOA Process consists of the followingSteps:1. Identify the Actors.2. Develop a simple business processmodel using UML Activity diagram.3. Develop the Use Case.4. Develop interaction diagrams.5. Identify classes. Sahaj Computer SolutionsObject Oriented Systems Development57
Object--Oriented DesignObjectBooch provides the most comprehensive objectoriented design method. Ironically, since it is so comprehensive, themethod can be somewhat imposing to learn andespecially tricky to figure out where to start. Rumbaugh et al.'s and Jacobson et al.'s high-levelmodels provide good avenues for getting started. UA combines these by utilizing Jacobson et al.'sanalysis and interaction diagrams, Booch's objectdiagrams, and Rumbaugh et al.'s domain models. Sahaj Computer SolutionsObject Oriented Systems Development58
Object--Oriented DesignObject OOD Process consists of: Designing classes, their attributes, methods,associations, structures and protocols, applydesign axioms Design the Access Layer Design and prototype User interface User Satisfaction and Usability Tests based onthe Usage/Use Cases Iterate and refine the designSahaj Computer SolutionsObject Oriented Systems Development59
Iterative Development andContinuous TestingYou must iterate and reiterate until, eventually,you are satisfied with the system. Since testing often uncovers design weaknessesor at least provides additional information youwill want to use, repeat the entire process, takingwhat you have learned and reworking your designor moving on to reprototyping and retesting. Continue this refining cycle through thedevelopment process until you are satisfied withthe results. During this iterative process, your prototypes willbe incrementally transformed into the actualapplication. Sahaj Computer SolutionsObject Oriented Systems Development60
Modeling Based on the UnifiedModeling Language The unified modeling language wasdeveloped by the joint efforts of the leadingobject technologists Grady Booch, IvarJacobson, and James Rumbaugh withcontributions from many others.The UML merges the best of the notationsused by the three most popular analysis anddesign methodologies: Booch's methodology,Jacobson et al.'s use case, and Rumbaugh etal.'s object modeling technique.Sahaj Computer SolutionsObject Oriented Systems Development61
Modeling Based on the UnifiedModeling Language The UML is becoming the universallanguage for modeling systems; it isintended to be used to express models ofmany different kinds and purposes, just asa programming language or a naturallanguage can be used in many differentways.Sahaj Computer SolutionsObject Oriented Systems Development62
The UA Proposed Repository In modern businesses, best practice sharingis a way to ensure that solutions to processand organization problems in one part of thebusiness are communicated to other partswhere similar problems occur.The idea promoted here is to create arepository that allows the maximum reuseof previous experience and previouslydefined objects, patterns, frameworks, anduser interfaces in an easily accessible mannerwith a completely available and easily utilizedformat.Sahaj Computer SolutionsObject Oriented Systems Development63
The UA Proposed Repository Everything from the original user request tomaintenance of the project as it goes toproduction should be kept in the repository.The advantage of repositories is that, if yourorganization has done projects in the past,objects in the repositories from thoseprojects might be useful.You can select any piece from a repositoryfrom the definition of one data element, to adiagram, all its symbols, and all theirdependent definitions, to entries—for reuse.Sahaj Computer SolutionsObject Oriented Systems Development64
The UA Proposed RepositoryThe same arguments can be made about patternsand frameworks. Specifications of the software components,describing the behavior of the component andhow it should be used, are registered in therepository for future reuse by teams ofdevelopers. The repository should be accessible to manypeople. Furthermore, it should be relatively easy tosearch the repository for classes based on theirattributes, methods, or other characteristics. Sahaj Computer SolutionsObject Oriented Systems Development6
object-oriented system. You start with class and object diagram in the analysis and refine these diagrams in various steps. Only when you are ready to generate code the Booch method shines and you can document your object oriented code. Sahaj Computer Solutions Object Oriented Systems Development 12
Object Class: Independent Protection Layer Object: Safety Instrumented Function SIF-101 Compressor S/D Object: SIF-129 Tower feed S/D Event Data Diagnostics Bypasses Failures Incidences Activations Object Oriented - Functional Safety Object: PSV-134 Tower Object: LT-101 Object Class: Device Object: XS-145 Object: XV-137 Object: PSV-134 Object .
method dispatch in different object-oriented programming languages. We also include an appendix on object-oriented programming languages, in which we consider the distinction between object-based and object-oriented programming languages and the evolution and notation and process of object-oriented analysis and design, start with Chapters 5 and 6;
object-oriented programming language is based on a kind of old object-oriented programming language. For example, though C language is an object-oriented programming language, it still retains the pointer which is complex but has strong function. But C# improved this problem. C# is a kind of pure object-oriented language.
Reusability, CK Metric, Object - Oriented. 1. INTRODUCTION Object oriented systems continue to share a major portion of software development and customer base for these systems is on the rise. This is because there are many advantages in taking the object oriented concept. The weakness though is that most object oriented systems tend to be .
Object built-in type, 9 Object constructor, 32 Object.create() method, 70 Object.defineProperties() method, 43–44 Object.defineProperty() method, 39–41, 52 Object.freeze() method, 47, 61 Object.getOwnPropertyDescriptor() method, 44 Object.getPrototypeOf() method, 55 Object.isExtensible() method, 45, 46 Object.isFrozen() method, 47 Object.isSealed() method, 46
2 Database System Concepts 8.3 Silberschatz, Korth and Sudarshan Object-Oriented Data Model! Loosely speaking, an object corresponds to an entity in the E- R model.! The object-oriented paradigm is based on encapsulating code and data related to an object into single unit.! The object-oriented data model is a logical data model (like
as object–oriented design. Object–oriented development approaches are best suited to projects that will imply systems using emerging object technologies to construct, manage, and assemble those objects into useful computer applications. Object oriented design is the continuation of object-oriented analysis,
Alfredo López Austin viene del Norte, de Chihuahua, de Ciudad Juárez, para mayor precisión. Nació en aquellas regiones de desiertos y climas extremos que fraguan de manera tan peculiar el espíritu de quienes ven el mundo por primera vez en esas latitudes. La primera parte de la vida de mi maestro fue muy rica, envidiablemente rica en experiencias. Cuando recuerdo alguno de los pasajes de .
