ThoughtWorksThoughtWorks

NEAL FORD software architect / meme wrangler

ThoughtWorks

nford@thoughtworks.com 3003 Summit Boulevard, Atlanta, GA 30319

www.nealford.com

www.thoughtworks.com

blog: memeagora.blogspot.com

twitter: neal4d

visualizations for code metrics

housekeepingask questions anytime

download slides from nealford.com

download samples from github.com/nealford

point it to a subversion repository

code_swarm

http://code.google.com/p/codeswarm/

useful? cool!

visualization of check-ins over time

what was that?

http://www.wired.com/wired/issue/16-07

wtf’s/min

external perspective

is the software valuable to its users?

how easy is it to understand & extend?

how appropriate is the design?

how amenable is emergent design?

is it salvageable?

how maintainable is it?

internal perspective

30,000 feet ground level

http://opensimulator.org/wiki/Grid_Architecture_Diagram

where are the defects?

which way do the messages flow?

systems evolve locally, often uncontrolled

models created up front convey a vision but usually don’t reflect reality

generating a complete model for large systems is nearly impossible

need tools to create ad-hoc models more easily

the best picture very much depends on the question you are trying to answer

where do the pictures come from?

a class is a box with name, methods, fields,...

a model that describes a model

example: meta-model for a class diagram

rules: no circles in inheritance, etc.

available connectors: association, inheritance, aggregation…

1. select a meta-model

common meta-models

Clas

s

M1 M2 M3

Foo 3.4 3.8 6.5

Bar 5.0 0.0 10.0

… … … …

M1

M2

Foo

Bar

xyz

M1

Metrics (Quantitative) Directed Graph

Tree Process Model (e.g. Petri Net)

byte code

static analysis

source code

profiling, listen to messages, log files, network sniffer, etc.

dynamic analysis

2. inspection / instrumentation

3. mapping to the model

Mapper

Comp. Channel

A X

B Y

Comp. Channel

C X

C Y

Senders Receivers

Nodes: A, B, CEdges: X(A!C) Y(B!C)

Graph Model

example: messaging system

capture send/receive actions

map onto directed graph

4. visualization &...

Graphviz

enforce rules or best practices

don’t simply observe

verify & alert

islands on a dependency graph

detect cycles

...validation

the hawthorne effect

measure and let it be known that you are measuring

the hawthorne effect

metrics

cyclomatic complexitymeasures complexity of a function

V(G)= e - n + 2V(G) = cyclomatic complexity of Ge= # edgesn= # of nodes

start

if (c1)

f1() f2()

if (c2)

f3() f4()

end

start

if (c1)

f1() f2()

if (c2)

f3() f4()

end

7

65

4

32

1

8

7

65

4

3

2

1

nodes

edges

chidamber & kemererobject-oriented metrics

shyam r chidamberchris f kemerer

easy but not terribly useful very useful

easy (but trivial)

dit depth of inheritance tree # levels of inheritance

noc number of children # immediate descendants

npm number of public methods

# public methods in class

very usefulwmc weighted methods/

class ∑ of cyclomatic complexity

rfc response for class # of methods executed due to method call

lcom lack of cohesion ∑ of sets of methods not shared via sharing fields

cbo/ce

efferent couplings ∑ of other classes this class uses (outgoing calls)

ca afferent couplings ∑ of how many other classes use this class (incoming calls)

visualizations

lines, statements, % branches, calls, % comments, classes, methods/class, avg stmts/method, max complexity, max depth, average depth, average complexity

freeware tool for gathering metrics

metrics:

graphical user interface, windows only!

source monitor

source monitor:kiviat graphs

source monitor:class summary

source monitor w/ c#

classes that violate several kiviat graph ranges

really odd shapes

looking for...

“A project dedicated to making code metrics so widely understood, valuable, and simple that their use becomes ubiquitous, thus raising the quality of software across

the industry.”

jdepend

code coverage with emma1-line change to switch to cobertura

checkstyle1-line switch for custom rule sets

volatility

javancss

panopticode parts

code duplication using simian

aggregator & reports

treemaps

complexity treemap

code coverage

20,000 foot view along a single dimension

simple view of one dimension

information radiators

looking for...

allows comparison to “industry standards”

developed at Universities of Berne and Lugano

shows key metrics and their relationships

created by iPlasma tool from source code

size & complexity pyramid

pyramid5.75 NOP 224

6.13 NOC 12895.69 NOM 7905 7905 NOM 2.79

0.26 LOC 44988 22039 CALLS 0.40CYCLO 11602 8798 FANOUT

iPlasma + Struts

vuze

low cyclomatic complexity / line

adherence to industry standards

low number of lines / method (see composed method pattern)

looking for...

GraphViz

e v e n t l i s t

d o t

f i l e

output

generating dot files

untangling jars

Kirk Knoernschildwww.kirkk.com

jar analyzer

xml output

t r a n s f o r m e d

graphical

struts 1.0

no “rats’ nests”

not that!

small number of one-way dependencies

no cycles

looking for...

Vizantant task to create a GraphViz DOT file from an ant build file

http://vizant.sourceforge.net/

ant 1.5

log4j

tomcat 3.3.1

from=“dist”

to=“prepare”

networks around common dependent elements

hot spots

more even distribution

think about extracting via macrodef

look for...

SpringVizXSLT => DOT for spring

dependencies

http://www.samoht.com/wiki/wiki.pl?SpringViz

SpringViz

overloaded dependencies

regularity

symmetry

isolated pockets

look for...

toxicity chart

provides easy to compare overview of quality

created with checkstyle + excel

toxicity chart

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

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java

BooleanExpressionComplexity ClassDataAbstractionCoupling ClassFanOutComplexity CyclomaticComplexity FileLength MethodLength NestedIfDepth AnonInnerLength ParameterNumber MissingSwitchDefault TreeWalker

test to code ratioLines of unit test code per line of production code

1 2 3 3.053.1 4 5 6 7 8 9 10 11 12 13 14 15 16 17

0.80

1.00

1.20

1.40

1.60

1/4/06

15/4/06

29/4/06

13/5/06

27/5/06

10/6/06

24/6/06

8/7/06

22/7/06

5/8/06

19/8/06

2/9/06

16/9/06

30/9/06

14/10/06

28/10/06

11/11/06

25/11/06

9/12/06

23/12/06

6/1/07

20/1/07

3/2/07

17/2/07

3/3/07

17/3/07

31/3/07

14/4/07

28/4/07

12/5/07

26/5/07

9/6/07

23/6/07

7/7/07

21/7/07

4/8/07

18/8/07

Releases Unit test LOC/LOC

created using unix tools + excel

cc / loc / releases

test-to-code ratio: higher is better

notifications along your key dimension

toxicity: high-spikes

deltas more interesting than raw numbers

complexity / loc: trends

look for...

founded in Stockholm by Ola Rosling, Anna Rosling Rönnlund and Hans Rosling

“Unveiling the beauty of statistics for a fact based world view.”

time-based statistical view of chart data

now realized in the google spreadsheet motion gadget

the data

motion chart gadget

symmetry

time-based trends

odd outliers along dimensions

fluidity

look for...

CodeCrawlerwww.inf.unisi.ch/faculty/lanza/codecrawler.html

CodeCrawler

written in VisualAge Smalltalk

academic graphical metrics tool

language independent

quirky but powerful

based on the Moose platform

CodeCrawler

provides system complexity view, class & package dependency view

graduate student project written by Jacopo Malnati (http://atelier.inf.unisi.ch/~malnatij/xray.php)

open-source software visualization plug-in for eclipse

model of the underlying Java project can be triggered and used by other plug-ins

x-ray

x-ray visualizing itself through via system complexity view

x-ray creates textual information and actions

install the plug-in

choose the Analyze Current Project action from the package explorer

visualizations characterized by entities positioned according to layouts and criterions

using x-ray

actions

project name

# classes

# methods# packages

lines of code

show dependencies

color tag

show/hide nodes

show/hide package content

open selected classes

snapshot image

class dependency view

system complexity view

package dependency view

polymetric views

system complexity view

anomalies of shape (provided by the inheritance tree)

tries to illustrate disharmonies in the design and implementation of a system.

identify big nodes (compared to the others)

view provides several different dimensions of metrics

system complexity view

positional metrics

system complexity view

color metrics

system complexity view

Azureus 3.0 (more than

500,000 lines of code)

x-ray itself

dependencies

incoming

outgoing

class & package dependency views

class dependency view

package dependency

Azureus packages

filtering (< 30 weight)

proximity alert

exuberant responsibility

towers (=> lots of code, lots of methods)

tangled dependencies

balance

natural partitions

look for...

10,000 ft view (literally)

CodeCity by Richard Wettel

http://www.inf.unisi.ch/phd/wettel/codecity.html

written in VisualWorks Smalltalk, atop the Moose platform

integrated environment for software analysis

software systems are visualized as interactive, navigable 3D cities

packages => districts

classes => buildings

CodeCity

citylyzer

building height => number of methods

written atop x-ray

inspired by CodeCity

packages => districts

width/length => number of attributes

Citylyzer

overly crowded neighborhoods

“real” cityscape

buildings that wouldn’t exist in the real world

would you live there?

abandoned parts of town

look for...

discuss on iteration boundaries

wire metrics & analysis into continuous integration

manually check often

fail the build with: xpath expressions & plugins jdepend-like unit tests

metrics + agility

single dimensions

intermediate altitude

information radiators

cool!

compelling evidence

summary

ThoughtWorks

This work is licensed under the Creative Commons Attribution-Share Alike 3.0 License.

http://creativecommons.org/licenses/by-sa/3.0/us/

?’splease fill out the session evaluationssamples at github.com/nealford

NEAL FORD software architect / meme wrangler

ThoughtWorks

nford@thoughtworks.com 3003 Summit Boulevard, Atlanta, GA 30319

www.nealford.com

www.thoughtworks.com

blog: memeagora.blogspot.com

twitter: neal4d