package com.atlassian.plugin.manager;
   
   import com.atlassian.plugin.ModuleDescriptor;
   import com.atlassian.plugin.PluginController;
   import com.google.common.base.Function;
   import com.google.common.base.Predicates;
   import org.slf4j.Logger;
   import org.slf4j.LoggerFactory;
   
  import javax.annotation.Nullable;
  
  import static com.google.common.collect.Iterables.filter;
  import static com.google.common.collect.Iterables.transform;
  
  /**
   * Safely extracts the module instance from module descriptors,
   * handling exceptions and disabling broken plugins as appropriate.
   *
   * @since 4.0
   */
  public class SafeModuleExtractor {
      private static final Logger log = LoggerFactory.getLogger(SafeModuleExtractor.class);
  
      private final PluginController pluginController;
  
      public SafeModuleExtractor(PluginController pluginController) {
          this.pluginController = pluginController;
      }
  
      /**
       * Safely extracts the module instance from the given module descriptors. This method will disable any plugin it
       * can't successfully extract the module instance from.
       */
      public <M> Iterable<M> getModules(final Iterable<? extends ModuleDescriptor<M>> moduleDescriptors) {
          return filter(
                  transform(
                          moduleDescriptors,
                          new Function<ModuleDescriptor<M>, M>() {
                              @Override
                              public M apply(@Nullable ModuleDescriptor<M> descriptor) {
                                  if (descriptor == null || descriptor.isBroken()) {
                                      return null;
                                  }
  
                                  try {
                                      return descriptor.getModule();
                                  } catch (final RuntimeException ex) {
                                      final String pluginKey = descriptor.getPlugin().getKey();
  
                                      log.error("Exception when retrieving plugin module {}, disabling plugin {}",
                                              descriptor.getCompleteKey(), pluginKey, ex);
  
                                      descriptor.setBroken();
                                      // Don't persist: don't want to create a snowflake config in Cloud instance,
                                      // and the module might work following restart if something has changed.
                                      pluginController.disablePluginWithoutPersisting(pluginKey);
                                      return null;
                                  }
                              }
                          }),
                  Predicates.notNull());
      }
  }