jDepend in Action（学院派作品）

    JDepend traverses Java class file directories and generates design quality metrics for each Java package. JDepend allows you to automatically measure the quality of a design in terms of its extensibility, reusability, and maintainability to manage package dependencies effectively.

    it includes some terminology , may be you could see at the JDepend plugin for Eclipse,so I will introduce them before we go on study,that is sweep some obstacle for our undergoing continuous refactoring.

    Number of Classes and Interfaces:

    The number of concrete and abstract classes (and interfaces) in the package is an indicator of the extensibility of the package.

    Afferent Couplings (Ca)

    The number of other packages that depend upon classes within the package is an indicator of the package's responsibility.

    Efferent Couplings (Ce)

    The number of other packages that the classes in the package depend upon is an indicator of the package's independence.

    Abstractness (A)

    The ratio of the number of abstract classes (and interfaces) in the analyzed package to the total number of classes in the analyzed package.The range for this metric is 0 to 1, with A=0 indicating a completely concrete package and A=1 indicating a completely abstract package.

    Instability (I)

    The ratio of efferent coupling (Ce) to total coupling (Ce + Ca) such that I = Ce / (Ce + Ca). This metric is an indicator of the package's resilience to change.The range for this metric is 0 to 1, with I=0 indicating a completely stable package and I=1 indicating a completely instable package.

    Distance from the Main Sequence (D)

    The perpendicular distance of a package from the idealized line A + I = 1. This metric is an indicator of the package's balance between abstractness and stability.

    A package squarely on the main sequence is optimally balanced with respect to its abstractness and stability. Ideal packages are either completely abstract and stable (x=0, y=1) or completely concrete and instable (x=1, y=0).

    The range for this metric is 0 to 1, with D=0 indicating a package that is coincident with the main sequence and D=1 indicating a package that is as far from the main sequence as possible.

    Package Dependency Cycles

    Package dependency cycles are reported along with the hierarchical paths of packages participating in package dependency cycles.

    when you use JDepend4Eclipsen(JDepend plugin for Eclipse),you will see some abbreviation ,so I will exhibit them:
   
    1.CC - Concrete Class Count
    2.AC - Abstract Class (and Interface) Count
    3.Ca - Afferent Couplings (Ca)    
    4.Ce - Efferent Couplings (Ce)
     5.A - Abstractness (0-1)
     6.I - Instability (0-1)
     7.D - Distance from the Main Sequence (0-1)
     8.V - Volatility (0-1)
     9.Cyclic - If the package contains a dependency cycle