Software Construction SWEBOK Chapter 4 Software Construction

Fundamentals Minimizing Complexity Anticipating Change Construction for Verification Standards in Construction

Minimizing Complexity One of the strongest drivers in software construction Required due to human limitations of memory

Minimizing Complexity How is complexity minimized during software construction? Use of standards Coding practices Construction-oriented quality techniques Creation of code that is simple and readable rather than clever

Anticipate Change Software will change Coding techniques can be used to make change easier (designing for change is also critical) Give potential causes for change

Construction for Verification Built is such a way to allow easy identification of defects By developers during construction By testers Identification by developers and individual testing

Construction for Verification Techniques Following coding standards Unit testing Organizing code to support automated testing Restricted use of complex/hard-to-understand language structures

Standards in Construction Communication methods Programming languages Platforms Tools External standards Internal standards Communication methods: document formats CSV or XML, SOAP web services or HTTP POST Tools: UML modeling External standards: hardware and software interface specifications from the OMG or IEEE Internal standards: organizational

Managing Construction Construction Models Construction Planning Construction Measurement

Construction Models Linear construction view Interative Construction only after significant pre-requisite work is complete Coding is main focus of construction Interative Construction occurs at the same time as other development activities Combination of activities all considered construction

Construction Planning How are we going to build it? Affects prerequisite activities Extent to which they are performed Order in which they are performed Degree to which they are expected to be complete before construction begins Affects project’s ability to minimize complexity, anticipate change, and construct for verification Defines the order in which components are created and integrated, QA management process, allocation of task assignments, etc.

Construction Measurement What aspects are being measured? Code developed (LOC) Code reused Code modified Code complexity Code inspection statistics Defects found Defects fixed Effort Scheduling Story points (velocity) Why do we need to measure construction?

Practical Considerations Construction Design Construction Languages Coding Construction Testing Reuse Construction Quality Integration

Construction Design Design done before construction will be incomplete Detailed design same as overall design but at a smaller scale Haven’t we already talked about design?

Construction Languages Anyway that a human can specify execution instructions to a computer Configuration Languages Toolkit Languages Programming Languages Configuration Languages are languages in which software engineers choose from a limited set of predefined options to create new or custom software installations. The text-based configuration files used in both the Windows and Unix operating systems are examples of this, and the menu style selection lists of some program generators constitute another. Toolkit languages are used to build applications out of toolkits (integrated sets of application-specific reusable parts), and are more complex than configuration languages. Toolkit languages may be explicitly defined as application programming languages (for example, scripts), or may simply be implied by the set of interfaces of a toolkit. Programming languages are the most flexible type of construction languages. They also contain the least amount of information about specific application areas and development processes, and so require the most training and skill to use effectively.

Coding Understandable source code Use of classes, enumerated types, variables, named constants, etc Control structures Error handling Prevention of code-level security breaches Resource usage Source code organization Code documentation Code tuning

Construction Testing Goal: to reduce the time between defect creation and default detection Subset of overall testing types performed by the engineer who wrote the code Unit testing Integration testing

Reuse Reuse processes and activities must be formalized into the software life cycle Selection of what to reuse Evaluation of code or test reusability Reporting of reuse information on new code

Construction Quality Common Techniques Unit and integration testing Test-first development Code stepping Use of assertions Debugging Technical reviews Static analysis Focus on code and not overall project

Integration Plan the sequence in which components will be integrated Creation of scaffolding and stubs to support interim versions Determining the degree of testing done on components before they are integrated Determine when interim versions of the software are tested