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  • Andreas Höhmann 13:41 am Monday, 24. August 2009 Permalink |
    Tags: code template, , extension point, Java, m2eclipse, , , , pom, version   

    Use Maven Artifact Version in Eclipse Code Templates 

    Based on waffel’s blog i wrote a eclipse plugin which provides the current artifact-version of a maven-project to the eclipse editor-templates. Waffel want to add the current plugin id/version to the @since field for class comments, i want to add the current version of my maven-eclipse-project. Let me explain my solution.

    It’s easy to add a new template-variable to eclipse, you can read this. Based on  org.eclipse.jface.text.templates.TemplateVariableResolver we can write a MavenVersionResolver:

     * Resolver to resolve variable <code>pomVersion</code>.
     * @author hoehmann
     * @since 1.0.0
    public class MavenVersionResolver extends TemplateVariableResolver {
      public MavenVersionResolver() {
      private String getMavenVersion(final IProject project) {
        if (project == null) {
          throw new IllegalArgumentException("Missing project"); //$NON-NLS-1$
        String result = ""; //$NON-NLS-1$
        try {
          if (project.hasNature(IMavenConstants.NATURE_ID)) {
            final MavenProjectManager projectManager = MavenPlugin.getDefault()
            final IMavenProjectFacade projectFacade = projectManager.create(
                project, new NullProgressMonitor());
            if (projectFacade != null) {
              final ArtifactKey mavenProject = projectFacade.getArtifactKey();
              if (mavenProject != null) {
                result = mavenProject.getVersion();
                // remove snapshot-indicator
                final int index = result.lastIndexOf("-SNAPSHOT"); //$NON-NLS-1$
                if (index != -1) {
                  result = result.substring(0, index);
        } catch (final CoreException ex) {
        return result;
       * {@inheritDoc}
      protected String resolve(final TemplateContext context) {
        // TODO better way to get the project?!
        return getMavenVersion(((CodeTemplateContext) context).getJavaProject()

    With the MavenProjectManager from m2eclipse we can create a IMavenProjectFacade, this facade returns the ArtifactKey and this key have the version. If the version is a snapshot-version we can cut this trailing string off and the result is the (next) version for our maven-project (for me it doesn’t make sense to add the snapshot-version into a @since comment because the release-version should be documented in the sourcecode).

    Maybe the check for the „m2eclipse“-nature is not necessary:

    if (project.hasNature(IMavenConstants.NATURE_ID)) {....}

    I tried without the nature-check and it works. The project must contain a „pom.xml“ to get a IMavenProjectFacade.

    This was the first part of the solution. The placeholder „pom_version“ will be available for all editor-templates in the „java-context“:


    Waffel described already a solution (a workaround) to use a editor-template-resolver in the code-templates. He registered a IStartup class which copies his own BundleIdResolver/BundleVersionResolver into the (internal) code-template-context-registry of the Eclipse-Java-Plugin. For waffel this was fine because he doesn’t register his resolvers as editor-template-resolvers. I want use my MavenVersionResolver in all java-templates and in the code-templates.

    And i don’t want create a new instance of the resolver, i want reuse the extension-point-configured resolver. So i have only one place to define my resolver (type = ‚pom_version‘, localized name, localized description, class etc.).

    I found a other way to register the resolver

    1. i search my MavenVersionResolver in the registered editor-templates (java-context)
    2. if i found one, i add this reference to the (internal) code-template-registry

     * Currently it's not possible to provide more variables for
     * <tt>java-code-templates</tt>, we can only add more <tt>editor-templates</tt>
     * via extension-point.
     * <p>
     * This {@link IStartup} is a workaround to register our
     * {@link MavenVersionResolver} for <tt>java-code-templates</tt> too.
     * </p>
     * @author hoehmann
     * @since 1.0.0
    public class RegisterResolvers implements IStartup {
      private static final String JAVA_PLUGIN_ID = "org.eclipse.jdt.ui"; //$NON-NLS-1$
       * Add our resolver to each registered code-template-context.
       * @param javaPlugin
       *          must not be <code>null</code>
       * @param mavenVersionResolver
       *          must not be <code>null</code>
      private void addMavenVersionResolver(final JavaPlugin javaPlugin,
          final MavenVersionResolver mavenVersionResolver) {
        final ContextTypeRegistry codeTemplateContextRegistry = javaPlugin
        final Iterator ctIter = codeTemplateContextRegistry.contextTypes();
        while (ctIter.hasNext()) {
          final TemplateContextType contextType = (TemplateContextType) ctIter
       * {@inheritDoc}
      public void earlyStartup() {
        // check if plug-in org.eclipse.jdt.ui is final already active
        final Bundle bundle = Platform.getBundle(JAVA_PLUGIN_ID);
        if (bundle != null && bundle.getState() == Bundle.ACTIVE) {
        } else {
          // register listener to final get informed, when plug-in final becomes
          // active
          final BundleContext bundleContext = Activator.getDefault().getBundle()
          bundleContext.addBundleListener(new BundleListener() {
            public void bundleChanged(final BundleEvent pEvent) {
              final Bundle eventBundle = pEvent.getBundle();
              if (!eventBundle.getSymbolicName().equals(JAVA_PLUGIN_ID)) {
                // ignore other plugins
              if (eventBundle.getState() == Bundle.ACTIVE) {
       * Try to find our {@link MavenVersionResolver} in the java-plugin
       * template-context-registry.
       * @param javaPlugin
       *          must not be <code>null</code>
       * @return
      private MavenVersionResolver getMavenVersionResolver(
          final JavaPlugin javaPlugin) {
        final ContextTypeRegistry contextRegistry = javaPlugin
        final TemplateContextType javaContextType = contextRegistry
        final Iterator<TemplateVariableResolver> resolvers = javaContextType
        MavenVersionResolver mavenVersionResolver = null;
        while (resolvers.hasNext()) {
          final TemplateVariableResolver resolver =;
          if (resolver instanceof MavenVersionResolver) {
            mavenVersionResolver = (MavenVersionResolver) resolver;
        return mavenVersionResolver;
       * First find the maven-version-resolver from the registered resolvers.
      private void registerResolvers() {
        final JavaPlugin javaPlugin = JavaPlugin.getDefault();
        if (javaPlugin == null) {
          throw new IllegalStateException(String.format(
              "Expected plugin '%s' is not available", JAVA_PLUGIN_ID));
        final MavenVersionResolver mavenVersionResolver = getMavenVersionResolver(javaPlugin);
        if (mavenVersionResolver != null) {
          addMavenVersionResolver(javaPlugin, mavenVersionResolver);

    Now its possible to use „pom_version“ in code-templates too:


    Now the final test  …  create a „normal“ java-project, create a new class. The javadoc will not contain a version (the project doesn’t have a maven-nature):


    If the project is a „real“ maven project the version will be available:


    If anyone need the plugin … leave a comment.

  • Andreas Höhmann 14:11 am Tuesday, 26. August 2008 Permalink |
    Tags: decompile, jad, jadalign, jar, Java   

    Howto decompile a complete jar-file 

    Download JAD and jadAlign. Unpack the zips and copy the two executables in a path-directory. Put this little shell-script in your path.

    mkdir src 2>/dev/null
    cp $1 src/$
    cd src/
    unzip $
    rm -f $
    find . -name "*.class" -exec jad -r -s "jad" -lnc {} \;
    find . -name "*.class" -exec rm -f {} \;
    find . -name "*.jad"   -exec jadAlign {} `basename {} .jad`.java \;
    find . -name "*.jad"   -exec rm -f {} \;
    cd $OLD_PWD

    Open a shell (under windows you can use cygwin), change to the directory where the jar-file can be found and call jar2decompile.jar

    At the end you should have a new directory src with the decompiled and re-aligned java-sources.

    Try it 🙂

    • thomaswabner 10:39 am Mittwoch, 27. August 2008 Permalink | Zum Antworten anmelden

      Very nice and interesting! Thanks.

      Some hints and questions about the shell script.

      Why you need the „OLD_PWD“ stuff? You can simple

      mkdir src
      cd src
      .. do anything
      cd ..

      The find command should also called with
      find -type f

      to aviod executing jad and the other tools to run on a directory.

      The mkdir can be used better with
      mkdir src > /dev/null 2>&1
      to also grab the stdout

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