#Maven - Shredzone

Fluido skin and Markdown syntax highlighting

doxia-module-markdown is a Maven plugin that enables Markdown in Maven documentations. In version 1.8, the developers have moved from Pegdown to Flexmark as Markdown parser. It's a good choice, as Flexmark is considerable faster and is still being maintained, while Pegdown officially reached its end of life in 2016.

However, with that switch, code blocks are not syntax highlighted any more. The reason is that the maven-fluido-skin uses code-prettify for syntax highlighting. It runs browser-side, highlighting all <pre> and <code> blocks selecting the prettyprint CSS class. This was true with Pegdown, but Flexmark selects a source class instead.

An obvious workaround is to use a small JavaScript snippet that adds a prettyprint class to all blocks selecting a source class, and then running prettyPrint() again. To do so, this block needs to be added to the <head> section of site.xml:

<head>
  <!-- Workaround for https://issues.apache.org/jira/browse/DOXIA-571 -->
  <![CDATA[<script type="text/javascript">
    $(document).ready(function () {
      $(".source").addClass("prettyprint");
      prettyPrint();
    });
  </script>]]>
</head>

It's hard to tell if this is a bug in doxia-module-markdown or in maven-fluido-skin. Also see my bug report at Apache's JIRA.

This was a Google Plus comment that I have now moved to my blog as Google Plus is going to be closed. Thanks to Clement Escoffier for the inspiration.

Hibernate 4 schema generation with Maven

While upgrading my blog software Cilla to Java 8 and Hibernate 4, I found out that the old hibernate3-maven-plugin refused to create schema.sql files. Well, it wasn't really surprising. The name of the plugin already implied that the plugin won't play with the next major release of Hibernate.

I could not spot an official update of the plugin. Instead, I found Kai Moritz new Hibernate 4 maven plugin, which turned out to be very useful.

One key feature is to set up and initialize a local database for unit testing. I don't need this feature for Cilla (yet 😉). All I need is a hbm2ddl style generation of a SQL schema file for setting up new instances of my blog software from scratch. It turned out that the plugin was easily configured that way, and so it got almost a drop-in replacement for the old plugin.

This is what the <plugins> section of the project's pom file looks like:

<plugin>
    <groupId>de.juplo</groupId>
    <artifactId>hibernate4-maven-plugin</artifactId>
    <version>1.0.4</version>
    <executions>
        <execution>
            <goals>
                <goal>export</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <hibernateDialect>org.hibernate.dialect.PostgreSQL82Dialect</hibernateDialect>
        <target>NONE</target>
        <type>CREATE</type>
    </configuration>
</plugin>

With the target set to NONE, the schema.sql file is quietly generated while building the project. If set to SCRIPT, a copy will be dumped to stdout.

A CREATE type only generates create statements of the database. The default is BOTH, which creates drop and create statements.

Since no actual database is created, there is no need to add user, password and url parameters.

A list of all configuration options can be found here. The plugin is available at Maven Central.

hibernate3-maven-plugin fails with Java 1.7

If you're using Maven's hibernate3-maven-plugin for creating a DDL file from your entities, you might encounter the following error when using Java 1.7:

Execution default of goal org.codehaus.mojo:hibernate3-maven-plugin:2.2:hbm2ddl failed:
An AnnotationConfiguration instance is required

The reason seems to be a broken JRE detection in the Mojo code, which mistakenly assumes that Java 1.7 does not support annotations. However, I haven't checked that in depth.

The fix is pretty easy. In the plugin configuration of the hibernate3-maven-plugin, add an implementation property to the componentProperties like this:

<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>hibernate3-maven-plugin</artifactId>
  <version>2.2</version>
  <configuration>
    <componentProperties>
      <implementation>annotationconfiguration</implementation>
    </componentProperties>
  </configuration>
</plugin>

This enforces the use of an AnnotationConfiguration instance.