Analysis and measurement of software flexibility based on flexible points

Software flexibility is one of the properties that indicate if the software is easy to change. Flexible software can easily adapt to user requirement and/or environment changes during the software development period or after the software is deployed. In this paper, we introduce two new concepts, flexible change and FleXible Point( FXP). Associated with the flexible point, a set of flexibility indexes, i.e. flexible degree, flexible force, flexible distance, flexible capacity and their calculation formulas are defined. We further present a schema that utilizes these new concepts and indexes to quantitatively measure software flexibility. The software flexibility related properties. They are software adaptability, brittleness, rigidity, elasticity and plasticity, are also discussed and analysed. The flexible points are categorized into five different types: potential FXP, available FXP, used FXP, current FXP, and required FXP, and four different levels: Self-Adaptive FXP, Low-level User FXP, High-level User FXP, and Developer-Level User FXP. The relations and differences between flexible points and their impact on the software development, maintenance and quality are discussed. Measuring process of software flexibility based on flexible point is represented. A simple case study is carried out to illustrate the analysis and measurement of software flexibility. The metric in the paper can be used to guide software developers to determine and improve the flexibility of their software applications and to compare their flexibilities among different software systems or different version.