jQAssistant Java Metrics Plugin

Table of Contents

How It Works
- OOD-Metrics
- Visibility Metrics
Usage
Link
Feedback
Acknowledgements

NOTE: This project has been archived and is no longer actively developed. Please refer to the existing releases and documentation.

This project provides a jQAssistant plugin to measure some widely known metrics.

How It Works

OOD-Metrics

The OOD metrics were described first by Robert C. Martin. He described several metrics:

Normalized Distance - It’s very similar to distance, but in normalized range.
Distance - The distance from the "main sequence"
- Instability - Relative number describes the stability of a package.
  - Afferent Couplings - Absolute number of incoming dependencies.
  - Efferent Couplings - Absolute number of outgoing dependencies.
- Abstractness - Relative number describes the abstractness of a package.
  - Number Classes - Absolute number of classes in a package.
  - Number Abstracts - Absolute number of abstract classes in package.

Visibility Metrics

Relative Visibility - Relative number describes the outside visible elements.

Usage

Prerequisites

Java 8 or higher
Maven 3.2.5 or higher
jQAssistant 1.8.0 or higher (see below)

Setup

The plugin can be enabled in Maven based project by adding it as a dependency to the jQAssistant Maven plugin:

pom.xml

<build>
    <plugins>
        <plugin>
            <groupId>com.buschmais.jqassistant</groupId>
            <artifactId>jqassistant-maven-plugin</artifactId>
            <version>1.8.0</version>
            <executions>
                <execution>
                    <goals>
                        <goal>scan</goal>
                        <goal>analyze</goal>
                    </goals>
                    <configuration>
                        <concepts>
                            <concept>ood-metrics:NormalizedDistance</concept>               <!--(1)-->
                            <concept>visiblity-metrics:RelativeVisibility</concept>
                        </concepts>
                    </configuration>
                </execution>
            </executions>
            <dependencies>
                <dependency>                                                                <!--(2)-->
                    <groupId>org.jqassistant.contrib.plugin</groupId>
                    <artifactId>jqassistant-java-metrics-plugin</artifactId>
                    <version>1.8.0</version>
                </dependency>
            </dependencies>
        </plugin>
    </plugins>
</build>

Configure wanted the concepts of the plugin.
Declares the plugin as dependency of jQAssistant

Application of the results

Manually query the results

Query some OOD-Metrics of package a.b.c

MATCH
  (p:Java:Package {fqn:"a.b.c"})
RETURN
  p.normalizedDistance, p.abstractness, p.instability

Usually you won’t query the results manually. Instead you’ll implement your own rule to check if packages meet your requirements.

Rule

jqassistant/my-rules.xml

<jqa:jqassistant-rules xmlns:jqa="http://www.buschmais.com/jqassistant/core/rule/schema/v1.3">
    <constraint id="my-rule:NormalizedDistance">
        <requiresConcept refId="ood-metrics:NormalizedDistance"/>
        <description>The Normalized Distance of package a.b.c must be lower or equals than 0.2.</description>
        <cypher><![CDATA[
            MATCH (p:Package {fqn:"a.b.c"})
            WHERE p.normalizedDistance > 0.2
            RETURN p
        ]]></cypher>
    </concept>
</jqa:jqassistant-rules>

This constraint will return the package a.b.c if its Normalized Distance is greater than 0.2. By using the default settings this will break your build.

Reference

All properties are created at a Node with Label :Java:Package.

Table 1. All properties created by this plugin

Property	Description	Created by
ca	Afferent couplings	ood-metrics:AfferentCouplings ood-metrics:Instability ood-metrics:Distance ood-metrics:NormalizedDistance
ce	Efferent couplings	ood-metrics:EfferentCouplings ood-metrics:Instability ood-metrics:Distance ood-metrics:NormalizedDistance
instability	Instability	ood-metrics:Instability ood-metrics:Distance ood-metrics:NormalizedDistance
nc	Number Classes	ood-metrics:NumberClasses ood-metrics:Abstractness ood-metrics:Distance ood-metrics:NormalizedDistance
na	Number Abstracts	ood-metrics:NumberAbstracts ood-metrics:Abstractness ood-metrics:Distance ood-metrics:NormalizedDistance
abstractness	Abstractness	ood-metrics:Abstractness ood-metrics:Distance ood-metrics:NormalizedDistance
distance	Distance	ood-metrics:Distance
normalizeDistance	Normalized Distance	ood-metrics:NormalizedDistance
relativeVisibility	Relative Visibility	visibility-metrics:RelativeVisibility

Link

Calculate metrics

https://101.jqassistant.org/calculate-metrics/index.html

Feedback

Please report any issues.

Acknowledgements

This plugin could not provide its functionality without the support of the following open source projects:

jqassistant-archive / jqassistant-java-metrics-plugin Goto Github PK