anchor.diff:  
   To author your Maven-generated site in AsciiDoc, you must first add a dependency on the Asciidoctor plugin to your maven-site-plugin config:
   
  -[source,xml]
  +[source,xml,subs=attributes+]
   .Maven site integration
   -----
   <build>
  
positive.code: .Plugin configuration options
  ----
  <plugin>
    ...
      </executions>
      <configuration>
        <sourceDirectory>src/main/doc</sourceDirectory>
        <outputDirectory>target/docs</outputDirectory>
        <backend>html</backend>
        <doctype>book</doctype>
        <attributes>
          <stylesheet>my-theme.css</stylesheet>
        </attributes>
      </configuration>
      ...
  </plugin>
  ...
  ----
  
  ==== Passing POM properties
  
  It is possible to pass properties defined in the POM to the Asciidoctor processor. This is handy for example to include in the generated document the POM artifact version number.
  
  This is done by creating a custom Asciidoc property in the `attributes` section of the `configuration`. The Asciidoc property value is defined in the usual Maven way: `${myMavenProperty}`.
  
  [source,xml]
  ----
  <attributes>
      <docVersion>${project.version}</docVersion>
  </attributes>
  ----
  
  The custom Asciidoc property can then be used in the document like this `Version: {docVersion}`.
  
  [NOTE]
  ====
  If you want to have the project version as the revision number of the document, use this construct:
  
   :revnumber: {docVersion}
  
  This will make the version number appear in the header and footer of the output.
  ====
  
  ==== Setting boolean values
  
  Boolean attributes in asciidoctor, such as `numbered`, `toc`, `copycss` or `linkcss!` can be set with a value of `true` or unset (in the case of `linkcss` vs `linkcss!`) with a value of false.
  
  ==== Examples
  
  In the `attributes` part of the Asciidoctor Maven Plugin configuration: 
  
  <numbered>true</numbered>
  
  You can find more information and many examples ready to copy-paste in the {asciidoctor-maven-examples}[asciidoctor-maven-examples] project.
  
  === Multiple outputs for the same file
  
  Maven has the ability to execute a Mojo multiple times. Instead of reinventing the wheel inside the Mojo, we'll push this off to Maven to handle the multiple executions.
  An example of this setup is below:
  
  [source,xml]
  .Multiple configuration extract
  ----
  <plugin>
      <groupId>org.asciidoctor</groupId>
      <artifactId>asciidoctor-maven-plugin</artifactId>
      <version>${asciidoctor.version}</version>
      <executions>
          <execution>
              <id>output-html</id>
  
negative.code:     <configuration>
          <sourceDirectory>src/main/asciidoc</sourceDirectory>
          <headerFooter>true</headerFooter>
          <imagesDir>../resources/images</imagesDir> <!--1-->
      </configuration>
  </plugin>
  ----
  <1> `imagesDir` should be relative to the source directory. It defaults to `images` but in this example the images used in the docs are also used elsewhere in the project.
  
  Any configuration specified outside the executions section is inherited by each execution.
  