code: private String getPluginSetting(MavenProject project, String pluginId, String optionName, String defaultValue) {
      Xpp3Dom dom = getPluginConfigurationDom(project, pluginId);
      if (dom != null && dom.getChild(optionName) != null) {
        return getValue(project, dom.getChild(optionName));
      }
      return defaultValue;
    }
docs: Search for a configuration setting of an other plugin.
  
  @param project      the current maven project to get the configuration from.
  @param pluginId     the group id and artifact id of the plugin to search for
  @param optionName   the option to get from the configuration
  @param defaultValue the default value if the configuration was not found
  @return the value of the option configured in the plugin configuration