Home > Articles > Programming > General Programming/Other Languages

  • Print
  • + Share This
This chapter is from the book

1.4 What Is a Software Object?

In 1976, Niklaus Wirth published his book Algorithms + Data Structures = Programs. This heightened our awareness of the major parts of a program. In 1986, J. Craig Cleaveland published his book Data Types. In 1979, Bjarne Stroustrup had started the work on C with classes. By 1985, the C++ Programming Language had evolved and in 1990 the book The Annotated C++ Reference Manual was published. I will talk primarily about COBOL and associated .NET Framework base classes and objects in this book, because this is the main focus of this book.

When Bjarne Stroustrup published his book on C++ or C with classes, we started associating the words class and object with the term "abstract data type." But what is the difference between data types and abstract data types? A data type is a set of values. Some algorithm then operates upon managing and changing the set of values. An abstract data type has not only a set of values, but also a set of operations that can be performed upon the set of values. The main idea behind the abstract data types is the separation of the use of the data type from its implementation. Figure 1–1 shows the four major parts of an abstract data type. Syntax and semantics define how an application program will use the abstract data type. Representation and algorithms show a possible implementation.

Figure 1-1Figure 1–1 Abstract Data Types

For an abstract data type, we have therefore defined a set of behaviors and a range of values that the abstract data type can assume. Using the data type does not involve knowing the implementation details. Representation is specified to define how values will be represented in memory. We call these representations class member variables in COBOL. The algorithm or programs specify how the operations are implemented. We call these programs member functions in COBOL. The semantics specify what results would be returned for any possible input value for each member function. The syntax specifies the COBOL operator symbols or function names, the number and types of all the operands, and the return values of the member functions. We are therefore creating our own data object (abstract data type) for the software to work with and use, as opposed to only using the data types predefined by the compiler, such as integer, character, and so on. These abstract data types or objects, as defined in Grady Booch's book Object-Oriented Analysis and Design, are as follows: "An object represents an individual, identifiable item, unit, or entity, either real or abstract, with a well-defined role in the problem domain."

We have slowly been coming to the realization of just what properties our program should have to make it work in solving complex real world problems. Having a new language paradigm like COBOL.NET and its associated capabilities to create classes and objects is not sufficient. We realized that just using the abstract data type or class was also not enough. So as part of this ongoing development, the methodology called object-oriented technology evolved what is called the object model. The software engineering foundation, whose elements are collectively called the object model, encompass the principles of abstraction, modularity, encapsulation, hierarchy, typing, concurrency, and persistence. The object model defines the use of these elements in such a way that they form a synergistic association.

As with any discipline, such as calculus in mathematics, we need a symbolism or notation in which to express the design of the objects. The creation of the COBOL.NET language, as an example, supplied one language notation needed to write our object-oriented programs. However, we still needed a notation for the design methodology to express our overall approach to the software development. In 1991 Grady Booch published his book, Object-Oriented Design with Applications, in which he defined a set of notations. These notations have become the defacto standard for object-oriented design. His second edition (1994) does an even better job of describing the overall object-oriented design notation and the object model. In this second edition he expresses all examples in terms of the C++ language, which has become a major language for object-oriented software development. We even have a Windows GUI tool based upon this notation to aid us in our thinking. This tool by Rational Corporation and Grady Booch was initially called ROSE. Quite a change from how calculus and its notation were initially used. We almost immediately have the same engine we wish to program on, aiding us in doing the programming. This tool has continued to evolve and is now called the Universal Modeling Language (UML).

An object (or component), then, is an entity based upon abstract data type theory, implemented as a class in a language such as COBOL.NET, and the class incorporates the attributes of the object model. What we have been describing, however, is just the tip of the iceberg relative to objects. The description so far has described the static definitions and has not talked about objects talking with one other. Let's look at one of the object model attributes, inheritance. Inheritance is our software equivalent of the integrated electronic circuit (IC) manufacturing technique of large-scale integration (LSI) that has allowed such tremendous advances in electronic system creations. Software using inheritance is certainly very small in scale at present, but the direction is set. Inheritance allows the creating of what I will call a small-scale integration (SSI) black box in software. This SSI creates what I will call an encapsulated software cluster of objects directed toward the solution of some function needed for the application. We have thus abstracted away a large amount of the complexity, and the programmer works only with the interfaces of the cluster. The programmer then sends messages between these clusters, just like the electronic logic design has wires between ICs, over which signals are sent.

While we allude to software components having an analogy to hardware chips, this is only true in a most general sense. Software components created with the rich vocabularies of the programming language, and based upon the constructs created by the programmer's mind, have a far greater range of flexibility and power for problem solving than hardware chips. Of course, therein lies a great deal of the complex nature of software programs. However, the software components ride on top of the hardware chips, adding another complete level of abstraction. I grant you that the deterministic logic involved in a complex LSI chip is very impressive. But the LSI chip is very limited in the possibility of forming any synergistic relationship with a human mental object. The more I dwell upon the direction of the .NET Framework base classes, in all its technologies, the more I feel we are externalizing the mind's use of mental object behavior mechanics. Certainly the object relationships formed with linking and embedding software objects, via interfaces, doesn't look much like the dendrite distribution of influences on clusters of neurons. But certainly now one software object is starting to effect one or more other software objects to accomplish its goal.

Let's look at a control object or collection of control objects from an everyday practical standpoint that we are using in other engineering fields. One of our early loves is the automobile. We can hardly wait to learn how to drive one. Notice we said drive one, any one. We have done such a great job on our encapsulation and interface exposure that we can learn to drive any kind and be able to drive any other kind. The automobile object we interact with has three primary interface controls: steering wheel, throttle, and brake. We realize that encapsulated within that automobile object is many internal functions. We can be assured that these control interfaces will not change from automobile object to automobile object. In other words, if we go from a General Motors car to a Ford car we can depend on the same functionality of these control interfaces.

Another characteristic of a software object is persistence. Persistence of an object is learned very early by a child. Eventually when we show a child a toy and then hide it behind our back, the child knows the toy still exists. The child has now conceptualized the toy object as part of his mental set of objects. As the programmer does a mental conceptualization of various software objects, this will lead to a high level of persistence of the objects in the programmer's mind. Since one of the main features of standard software objects is reusability, the efficiency of the programmer will continue to increase as the standard objects are conceptualized in the programmer's mental model.

Polymorphic behavior is another characteristic that can be implemented in a software object. Probably one of the earlier forms that a child realizes has different behavior, based upon form, is the chair object. The chair object is polymorphic in that its behavior depends on its form. We have rocking chairs, kitchen chairs, lounge chairs, and so on. This idea of form and related behavior has created a whole field of study called morphology. Certainly this is a key idea in how we relate cognitively to various objects. Not only does the clustering of our objects have form relationships, the internal constructs of the objects have a form relationship. There is a definite relationship between the logic flow of a program and the placement of the various meaningful chunks of a program. This is somewhat different than a pure polymorphic nature of a function, but does point out that we should be aware of the morphology of our objects and their parts.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020