 1. Introduction  2. Development Life-Cycle  3. Current Component Technologies  4. Component Quality Assurance  5. Advantages and Disadvantages

 What is component based software engineering (CBSE)? › Components › Component Model › Component Framework

 An abstract implementation of functionality that conforms to a component model.  Small systems for small pieces of functionality.  Designed by third party developers.

 Specify rules that must be obeyed by the components  Standardized Assumptions › Control Flow › Synchronization  Needed to remove sources of interface mismatches.

 Software services to support and enforce a component model.  Usually designed by the developer using the component model.  Can be viewed as a mini operating system

 1. Requirements Analysis  2. Software Architecture Selection  3. Component Identification and Customization  4. System Integration  5. System Testing  6. Software Maintenance

 Determine what functionality is required by client.  Look at requirements with possible components in mind.

 Choosing a component model to be used in your solution.  Determines what components will be available to you.  Different software architectures can be more appropriate than others based on the application.

 Most important phase of CBSE  Two main parts of this phase › 1. Evaluation of each component canidate › 2. Customization of the chosen components  Need to look at included functionality and customization options of each component.

 Bring all the chosen components together  Components are built on top of chosen architecture framework.  Other Tasks › Testing › Change and Reintegration

 Tests are needed for each individual component  Tests for the system framework  Testing of the components is limited  Less testing required for software components

 Correcting faults, improving system performance, and adapting the system.  Most controllable maintenance is done on the component architecture/framework  Maintenance of components handled primarily by developer of the component.

 Visual Basic Controls (VBX)  ActiveX controls  Class Libraries  JavaBeans  CORBA  COM

 Common object request broker architecture  Allows for communication between applications developed separately.  A server object call ORB controls things.  ORB locates the objects that clients call to use.

 Model consists of two parts › The clients side component development › Server side component development  Uses portable Java bytecodes and java applets trust security.  Offers a portable, secure, and reliable environment for developing robust components.

 Component object model  Defines how clients and components will interact  Provides a binary standard that components and clients must follow.  Extension of COM known as DCOM or distributed COM.

 Quality Characteristics of Components › Size › Complexity › Reuse Frequency › Reliability

 Components cannot be too large  Large components are costly and may not be cost effective until used multiple times.

 Makes the components difficult to use.  Overly simple components may not be beneficial for reuse.  Quality is more difficult to ensure with a complex system.

 The number of times that a component is used is a very valuable indicator of how useful a component is.  Offer financial saving, which can allow resources to be used elsewhere to improve quality.

 Probability of failure free operations.  Failing components can be easily replaced.

 How to certify quality of a component?  How to certify quality of software systems based on components?

 Independent extensions  Component Market  Component models lessen unanticipated interactions between components  Reduced time to market  Reduced Costs

 Time to develop software components takes a big effort.  Components can be pricey.  Requirements in component technologies lacking  Conflict between usability and reusability of components.  Maintenance cost for components increased.

 Component-Based Development  Components  Look at the quality of the components  Independent Extensions  Reduced Time-to-Market  Conflict between reusability and usability