Oberwald Rally

Ich habe heute ein kleines privates Projekt öffentlich zugänglich gemacht.

Das Projekt entstand im Rahmen unseres jährlichen Männertagstreffens (wir Leipziger HTWK Mappen feiern nicht nur einen Tag sondern gleich vier). Dieses Mal waren wir halt im schönen Oberwald. Der Tag war noch jung, ein paar Bier waren auch schon geleert … also was tun. Na dann einfach Mal etwas programmieren 😀 Ziel: „Rasende Roboter“ programmieren, am besten gleich einen Algorithmus schreiben, der das Problem automatisch löst. Das Projekt beschäftigt sich also mit dem Thema „Ricochet Robots“ (im dt. Rasende Roboter). Wie ich hier bereits schon schrieb, ist es eines meiner Lieblingsspiele 🙂

Das ganze Ding ist mittlerweile zu einem Eclipse PDE Projekt gereift … hier ein paar Screenshots …

Random Calculator View

Der RandomCalculator schiebt die 4 Roboter nach dem Zufallsprinzip über das Brett. Dabei kommt es ab und zu auch dazu, dass die Aufgabe (Roboter vom grünen Feld auf das rote Feld) gelöst wird 🙂

Graph Calculator View

Der GraphCalculator ist schon etwas „schlauer“, allerdings kann er nur den kürzesten Weg für einen Roboter berechnen.

Den Code gibts unter https://github.com/ahoehma/oberwaldrally.

Feedback erwünscht!

Viel Spass beim Bot schreiben!

😀

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() {
    super();
  }

  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()
            .getMavenProjectManager();
        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) {
      MavenLogger.log(ex);
    }
    return result;
  }

  /**
   * {@inheritDoc}
   */
  @Override
  protected String resolve(final TemplateContext context) {
    // TODO better way to get the project?!
    return getMavenVersion(((CodeTemplateContext) context).getJavaProject()
        .getProject());
  }
}

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) {
    Assert.isNotNull(javaPlugin);
    final ContextTypeRegistry codeTemplateContextRegistry = javaPlugin
        .getCodeTemplateContextRegistry();
    Assert.isNotNull(codeTemplateContextRegistry);
    final Iterator ctIter = codeTemplateContextRegistry.contextTypes();
    while (ctIter.hasNext()) {
      final TemplateContextType contextType = (TemplateContextType) ctIter
          .next();
      contextType.addResolver(mavenVersionResolver);
    }
  }

  /**
   * {@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) {
      registerResolvers();
    } else {
      // register listener to final get informed, when plug-in final becomes
      // active
      final BundleContext bundleContext = Activator.getDefault().getBundle()
          .getBundleContext();
      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
            return;
          }
          if (eventBundle.getState() == Bundle.ACTIVE) {
            registerResolvers();
            bundleContext.removeBundleListener(this);
          }
        }
      });
    }
  }

  /**
   * 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) {
    Assert.isNotNull(javaPlugin);
    final ContextTypeRegistry contextRegistry = javaPlugin
        .getTemplateContextRegistry();
    Assert.isNotNull(contextRegistry);
    final TemplateContextType javaContextType = contextRegistry
        .getContextType(JavaContextType.ID_ALL);
    Assert.isNotNull(javaContextType);
    final Iterator<TemplateVariableResolver> resolvers = javaContextType
        .resolvers();
    MavenVersionResolver mavenVersionResolver = null;
    while (resolvers.hasNext()) {
      final TemplateVariableResolver resolver = resolvers.next();
      if (resolver instanceof MavenVersionResolver) {
        mavenVersionResolver = (MavenVersionResolver) resolver;
        break;
      }
    }
    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.