public List<PluginPackage> getPluginPackages(String groupId, String artifactId) {

    List<PluginPackage> pluginPackages = new ArrayList<PluginPackage>();

    for (PluginPackage pluginPackage : _pluginPackages.values()) {
      if (pluginPackage.getGroupId().equals(groupId)
          && pluginPackage.getArtifactId().equals(artifactId)) {

        pluginPackages.add(pluginPackage);
      }
    }

    return pluginPackages;
  }
  public PluginPackage getLatestPluginPackage(String groupId, String artifactId) {

    PluginPackage latestPluginPackage = null;

    for (PluginPackage pluginPackage : _pluginPackages.values()) {
      if (pluginPackage.getGroupId().equals(groupId)
          && pluginPackage.getArtifactId().equals(artifactId)
          && ((latestPluginPackage == null)
              || pluginPackage.isLaterVersionThan(latestPluginPackage))) {

        latestPluginPackage = pluginPackage;
      }
    }

    return latestPluginPackage;
  }