dictionary of multimedia and internet applications: a guide for developers and users. francis botto

Print ISBN 0-471-98624-0 Online ISBN 0-470-84178-8

Object An entity within an OO program or system which has methods (or internal code) that determines its behaviour in response to stimuli such as events and messages. Objects are the currency of OO systems.

(See C++, Java and OOP.)

Object-based (See C++, Java* and OOP.)

Object factory A term sometimes used to describe software publishers,

who offer objects such as ActiveX controls, Java applets, JavaBeans, Plug-ins or OLE objects.

(See ActiveX*, Java*, Plug-in and OLE.)

Object implementation A coded solution which dictates an object’s be-

haviour and response to events. The code represents the object’s methods.

(See OOP.)

Object interface An object’s outer conceptual layer, which intercepts

messages and directs them appropriately. The layer is sometimes referred to as a shell. It is the first entity which an inbound message meets. The message may then be processed internally by the object’s methods.

(See Object* and OO*.)

Object-oriented (See C++, Java* and OOP.)

Object-Oriented Database Management System (See OODBC.)

Object-oriented language (See C++, Java* and OOP.)

Object-oriented programming (See C++, Java* and OOP.)

Object-oriented programming language (See C++, Java* and OOP.)

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Object-oriented UI

Object-oriented UI (See OO user interface.)

Object schema A structure that defines the interactions and relationship of objects in an OO system.

(See OO*.)

Object scraping A method of mapping data from a server to objects. The

objects are used to perform transactions or other types of processing. It may be applied in an application renovation solution.

(See Application renovation and Screen scraping.)

Occam 1. A programming language intended for developing software targeted at parallel systems such as supercomputers. It is closely aligned with the Transputer model for parallel processing. Named after William of Occam (circa 1300 to circa 1349), Occam is based on Co-operating Sequential Processes (CSP), which were originated by Tony Hoare. CSP puts forward the monitor concept, which coordinates tasks. Put simply, executing tasks are placed in monitors which are then locked, thus preventing other tasks from entering them. When the task is complete the monitor is unlocked, and may be entered by other tasks. Java is the first mainstream programming language to feature such concurrent program-ming features. Java objects have monitors, whose state is determined by the keyword synchronised. This is one of Java’s key attributes, but is rarely publicised. When synchronised, other threads cannot execute Java object methods that have begun executing as the result of a thread. In order to run such methods, threads must be able to obtain the object’s monitor lock. (See Java and MPP.) 2. An ancient philosophical principle that states we should not presume more to exist than is absolutely necessary. In the guise of Occam’s razor it loosely translates to: if you have two or more possible paths, then select the easiest. However, the convenient route in the short term often proves the most difficult later on.

OCR (Optical Character Recognition) A process that converts scanned images of text into text files.

Octet A term used to describe eight consecutive bits.

OCX A control or object which was a forerunner to ActiveX. OCX con-trols can be integrated into compatible applications, yielding functionality gains that may take the form of complete applications such as grammar checkers. OCX controls can be written using Visual C++.

(See ActiveX*, C++ and Visual Basic.)

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OLE1 and OLE2

ODBC (Open Database Connectivity) An internationally agreed standard,

covering database connectivity. Most modern databases offer ODBC compliance.

(See DBMS.)

ODBC 3.0 SDK A set of tools, libraries and headers which can be used to integrate ODBC 3.0 connectivity access in Web sites.

(See Data warehouse and ODBC.)

OLAP (On-Line Analytical Processing) A data analysis technique used

predominantly in the client/server computing environment. It is a decision-making support technique, which may be applied to interrogate data from disparate sources. The resulting data may also be analysed. OLAP imple-mentations can be assumed to embody multidimensional data analysis techniques, and to integrate:

● an OLAP GUI for user communication ● OLAP analytical processing logic ● OLAP data processing logic.

OLAP empowers users to generate query data in order to answer complex questions based on what-if scanarios or on current and historical data. It is an advancement of the primitive querying techniques harnessed in RDBMS designs. These include Borland (now Inprise) QBE and even query lan-guages such as the industry standard SQL.

(See Data warehouse, MOLAP and ROLAP.)

OLE1 and OLE2 (Object Linking and Embedding) An object archi-tecture. It is a method by which one application may be linked with or embedded into another. An OLE server application is the underlying source of an OLE client application. Objects may be video, wave audio, speech synthesis, MIDI files, graphics or text. The objects may be shown in the client OLE document or application as an icon, and can be launched by double clicking that icon. OLE can be used to embed Windows Media Player into client applications to add voice or video annotations to docu-ments. Using OLE1-compliant applications the process of embedding an object is more intensive than that associated with OLE2 applications. Object embedding is made easier using OLE2-compliant applications, be-cause objects can simply be dragged from one application to another. An increasing number of Window applications are OLE2-compliant.

(See ActiveX*.)

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OLE client

OLE client (Object Linking and Embedding client) An application which

has an embedded object or application from an OLE server application.

(See Object* and Visual Basic.)

OLE DB SDK A Microsoft database access specification which bases itself on OLE and COM object architectures. It complies with SQL and non-SQL databases.

(See Database, ODBC and ODBC 3.0 SDK.)

OLE server (Object Linking and Embedding server) An application which provides an object for an OLE client application, providing a means of running that object from within the client application.

(See Object* and Visual Basic.)

Online state A state in which a computer or peripheral can perform its

intended purpose. For example, a printer may print when it is online, and it is possible to communicate with a remote computer when it is online.

OO (Object-Orientated) A prefix used in object-oriented systems, software and development tools.

(See ActiveX*, C++, Java, JavaBeans, Object and OOP.)

OODBMS (Object-Oriented Database Management System.) A data-base used to store and to retrieve complete objects, including their code and their data. Stored objects may be categorised and stored in compound structures or objects. OODBMSes are characterised by their ability to:

● store complex objects

● be renovated or updated without radical renovation of data table struc-

tures associated with RDBMS implementations

● be extensible, providing a means of defining new data types ● support OO methodologies and concepts, including encapsulation, where

objects’ inner workings are hidden, and inheritance, where objects may be granted the methods and data of other objects. Multiple inheritance may also be supported where subclasses inherit methods and data from more than one superclass.

(See Data warehouse, DBMS, OO and OOP.)

OODL (Object-Orientated Dynamic Language) A programming lan-guage that is both object-orientated and dynamic, of which Dylan is a commercial example.

(See Dylan, Dynamic and OOP.)

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