private Service getService(File base) throws Exception {
    File dataFile = new File(base, "data");
    if (!dataFile.isFile()) return null;

    ServiceData data = getData(ServiceData.class, dataFile);
    return new Service(this, data);
  }
  public ArtifactData get(byte[] sha) throws Exception {
    String name = Hex.toHexString(sha);
    File data = IO.getFile(repoDir, name + ".json");
    reporter.trace("artifact data file %s", data);
    if (data.isFile()) { // Bin + metadata
      ArtifactData artifact = codec.dec().from(data).get(ArtifactData.class);
      artifact.file = IO.getFile(repoDir, name).getAbsolutePath();
      return artifact;
    }
    File bin = IO.getFile(repoDir, name);
    if (bin.exists()) { // Only bin
      ArtifactData artifact = new ArtifactData();
      artifact.file = bin.getAbsolutePath();
      artifact.sha = sha;
      return artifact;
    }

    return null;
  }
  /**
   * Constructor
   *
   * @throws IOException
   */
  public JustAnotherPackageManager(Reporter reporter, Platform platform, File homeDir, File binDir)
      throws IOException {
    this.platform = platform;
    this.reporter = reporter;
    this.homeDir = homeDir;
    if (!homeDir.exists() && !homeDir.mkdirs())
      throw new IllegalArgumentException("Could not create directory " + homeDir);

    repoDir = IO.getFile(homeDir, "repo");
    if (!repoDir.exists() && !repoDir.mkdirs())
      throw new IllegalArgumentException("Could not create directory " + repoDir);

    commandDir = new File(homeDir, COMMANDS);
    serviceDir = new File(homeDir, SERVICE);
    commandDir.mkdir();
    serviceDir.mkdir();
    service = new File(repoDir, SERVICE_JAR_FILE);
    if (!service.isFile()) init();

    this.binDir = binDir;
    if (!binDir.exists() && !binDir.mkdirs())
      throw new IllegalArgumentException("Could not create bin directory " + binDir);
  }
  public CommandData getCommand(String name) throws Exception {
    File f = new File(commandDir, name);
    if (!f.isFile()) return null;

    return getData(CommandData.class, f);
  }
  public CommandData parseCommandData(ArtifactData artifact) throws Exception {
    File source = new File(artifact.file);
    if (!source.isFile()) throw new FileNotFoundException();

    CommandData data = new CommandData();
    data.sha = artifact.sha;
    data.jpmRepoDir = repoDir.getCanonicalPath();
    JarFile jar = new JarFile(source);
    try {
      reporter.trace("Parsing %s", source);
      Manifest m = jar.getManifest();
      Attributes main = m.getMainAttributes();
      data.name = data.bsn = main.getValue("Bundle-SymbolicName");
      String version = main.getValue("Bundle-Version");
      if (version == null) data.version = Version.LOWEST;
      else data.version = new Version(version);

      data.main = main.getValue("Main-Class");
      data.description = main.getValue("Bundle-Description");
      data.title = main.getValue("JPM-Name");

      reporter.trace("name " + data.name + " " + data.main + " " + data.title);
      DependencyCollector path = new DependencyCollector(this);
      path.add(artifact);
      DependencyCollector bundles = new DependencyCollector(this);
      if (main.getValue("JPM-Classpath") != null) {
        Parameters requires = OSGiHeader.parseHeader(main.getValue("JPM-Classpath"));

        for (Map.Entry<String, Attrs> e : requires.entrySet()) {
          path.add(e.getKey(), e.getValue().get("name")); // coordinate
        }
      } else if (!artifact.local) { // No JPM-Classpath, falling back to
        // server's revision
        // Iterable<RevisionRef> closure =
        // library.getClosure(artifact.sha,
        // false);
        // System.out.println("getting closure " + artifact.url + " " +
        // Strings.join("\n",closure));

        // if (closure != null) {
        // for (RevisionRef ref : closure) {
        // path.add(Hex.toHexString(ref.revision));
        // }
        // }
      }

      if (main.getValue("JPM-Runbundles") != null) {
        Parameters jpmrunbundles = OSGiHeader.parseHeader(main.getValue("JPM-Runbundles"));

        for (Map.Entry<String, Attrs> e : jpmrunbundles.entrySet()) {
          bundles.add(e.getKey(), e.getValue().get("name"));
        }
      }

      reporter.trace("collect digests runpath");
      data.dependencies.addAll(path.getDigests());
      reporter.trace("collect digests bundles");
      data.runbundles.addAll(bundles.getDigests());

      Parameters command = OSGiHeader.parseHeader(main.getValue("JPM-Command"));
      if (command.size() > 1) reporter.error("Only one command can be specified");

      for (Map.Entry<String, Attrs> e : command.entrySet()) {
        data.name = e.getKey();

        Attrs attrs = e.getValue();

        if (attrs.containsKey("jvmargs")) data.jvmArgs = attrs.get("jvmargs");

        if (attrs.containsKey("title")) data.title = attrs.get("title");

        if (data.title != null) data.title = data.name;
      }
      return data;
    } finally {
      jar.close();
    }
  }