1. Static Software Metrics Tool
For Java
Course Project
CS 6367 Fall 2016
Aaron Leonard

2. Why software metrics?
Relation between software quality, measurements, and metrics
Static Java software metrics tool
Supported metrics
Unsupported metrics
Final plan
Questions

3. What/Why software metrics?
Software quality, measurements, and metrics
Metrics are how to measure quality
Can be applied to project management

4. Software quality, measurements, and metrics
How good or how bad is my software
Many conflicting definitions
We can define attributes of quality and try to measure them
Complexity
Maintainability
Presence of errors

5. Software quality, measurements, and metrics
Quantitative indication of some attribute we’re trying to measure
Complexity
How long to understand this code?
Relative to another? Scale of 1 to 10? Number of hours?
Maintainability
How hard is it to add some feature / fix some bug?
Presence of errors
Number of bugs

6. Software quality, measurements, and metrics
Quantitative value of some measurement
Where measurement indicates some attribute we're really interested in
Give a concrete value that really is observed
Some metrics may apply to more than one measurement
Some experts may disagree on the usefulness of a given metric

7. Java software metrics tool
Static software metrics
Just need to analyse the program source code off-line
Using ASM framework
As opposed to metrics derived from runtime behavior
Time executing, memory, CPU load, exceptions thrown, etc…
Test suite quality (you have to actually run it)
Code coverage (studied much in the class)

8. Supported metrics

9. Lines of code Baseline for many attributes Complexity Maintainability
Number of errors
Analogous to statement coverage in test suite metrics

10. Comments
Presence of/lines of comment
Related to maintainability

11. McCabe cyclomatic complexity
Number of paths in the control flow graph
Analogous to branch coverage in test suite metrics
Higher value is “more complex”

12. Halstead metrics Based on number of operations and operands Measures
Complexity
Maintenance
Number of bugs

13. Halstead volume Length = |operators| + |operands|
Vocabulary = |distinct(operators)|
+ |distinct(operands)|
Volume = Length * log(vocabulary)
Amount of code written
Larger for same lines of code implies more complex code

14. Halstead Effort, Time, Bugs
Difficulty =
distinct(operators)| / 2 * |operands| / |distinct(operands)|
How hard the code is to understand
Effort = Difficulty * Volume
How hard is it to write the same code from scratch
Time = Effort / 18
Value in seconds
Bugs = Volume / 3000

15. Maintainability index
Show maintainability on scale of 1 to 100
Composition of other metrics
( ln(Halstead volume)
* Cyclomatic complexity
* ln(Lines of code)) * 100 / 171
Derivation
Expert engineers rate software maintainability on scale of 1 to 100
Statistical analysis to combine the existing metrics to fit the expert opinion

16. Not supported Other complexity metrics Data flow
Comment quality metrics
Is the comment useful? Or noise
Object Oriented design metrics
Design reusability
Coupling
Cohesion

17. Final implementation plan
Given a java .class directory, create an HTML report of the supported metrics
Report would show break down by each package, class, and method
All supported metrics are implemented
But the report generation is not finished
Finish final report write up

18. Questions / comments