It is possible to define an external clover report descriptor file, the same way one can define a site.xml descriptor file. The descriptor file is basically a stripped down Ant file which will be run to produce the reports. All options available in clover-report can be specified. The default report descriptor used by the clover-maven-plugin is:

<project name="Clover Report" default="current">

    <clover-format id="clover.format" type="${type}" orderBy="${orderBy}" filter="${filter}"/>
    <clover-setup initString="${cloverdb}"/>

    <clover-columns id="clover.columns">
        <totalChildren/>
        <avgMethodComplexity/>
        <uncoveredElements format="raw"/>
        <totalPercentageCovered format="longbar"/>
    </clover-columns>


    <target name="historical">
        <clover-report>
            <current outfile="${output}"  summary="${summary}">
                <format refid="clover.format"/>
                <testsources dir="${tests}"/>
                <columns refid="clover.columns"/>
            </current>
            <historical outfile="${historyout}" historydir="${history}">
                <format refid="clover.format"/>
                <columns refid="clover.columns"/>
            </historical>
        </clover-report>
    </target>

    <target name="current">
        <clover-report>
            <current outfile="${output}" title="${title}" summary="${summary}">
                <format refid="clover.format"/>
                <testsources dir="${tests}"/>
                <columns refid="clover.columns"/>
            </current>
        </clover-report>
    </target>

</project>

This is a very simple Ant file, which defines two known targets: "historical" and "current" .
If there are no history points saved (via: clover:save-history) then only the "current" target will be called. Otherwise, the "historical" target gets called which generates both a historical and current report which are linked together.

To change Clover's default reporting behavior, it is easiest to copy this file and add the changes you require. For a full list of clover-report elements and attributes, please consult the clover-report documentation.

This file can be stored either on your local file system, or in your maven repository as a classified artifact.

If stored on the file system, set this system property:

-Dmaven.clover.reportDescriptor=/path/to/clover-report.xml

or specify this element:

<reportDescriptor>/path/to/clover-report.xml</reportDescriptor>

in the <configuration> element for the clover-maven-plugin in your pom.xml.

If you wish to keep this descriptor in your maven repository you must specify this system property:

-Dmaven.clover.resolveReportDescriptor=true

or set this element:

<resolveReportDescriptor>true</resolveReportDescriptor>

in the <configuration> element for the clover-maven-plugin in your pom.xml.
The descriptor should be deployed using the "clover-report" classifier. For example:

mvn deploy:deploy-file -DgroupId=my.group.id -DartifactId=my-artifact-id -Dversion=X.X -Dclassifier=clover-report \
 -Dpackaging=xml -Dfile=/path/to/file -Durl=[url] -DrepositoryId=[id]

Properties for Custom Reports

Standard Maven properties

A custom clover report descriptor can access the standard Maven 2 and 3 properties. The following properties are available:

• project.url
• project.version
• project.name
• project.description
• project.id
• project.groupId
• project.inceptionYear

In addition to these properties, any additional properties defined in pom.xml will also be available.

Clover configuration properties

Configuration options defined for clover:clover MOJO are available in report descriptor under following names:

• ${cloverdb} = full path to Clover database, depending on settings:
  
  • default database location (<build directory>/clover/clover.db) or
  • maven.clover.cloverDatabase or 
  • maven.clover.cloverMergeDatabase
• ${output} = full path to report directory or file:
  
  • absolute path of maven.clover.outputDirectory (HTML/JSON reports) or
  • maven.clover.outputDirectory + "/clover.pdf" (PDF report) or
  • maven.clover.outputDirectory + "/clover.xml" (XML report)
• ${history} = maven.clover.historyDir
• ${title} = report title, one of:
  
  • maven.clover.title or 
  • project's artifactId + version
  • in case when maven.clover.cloverMergeDatabase is set then the "(Aggregated)" word is appended
• ${titleAnchor} = maven.clover.titleAnchor
• ${projectDir} = project base dir
• ${testPattern} = "**/src/test/**"
• ${filter} = maven.clover.contextFilters
• ${orderBy} = maven.clover.orderBy
• ${charset} = maven.clover.charset
• ${type} = html / pdf / xml / json 
  
  • depends on maven.clover.generateHtml / maven.clover.generatePdf / maven.clover.generateXml / maven.clover.generateJson
  • custom report will be run for each of types enabled
• ${reportStyle} = style of the report ("adg" / "classic") - since Clover 4.0
• ${span} = maven.clover.span
• ${alwaysReport} = maven.clover.alwaysReport
• ${summary} = whether to generate a summary, true for PDF report
• ${historyout} = location of history report
  
  • ${output} for HTML
  • ${output}/historical.pdf for PDF