Creating an Information List Provider

To demonstrate Information List Providers, follow the instructions below to implement an InfoListProvider for the most viewed asset entries. In this case the list shows a list of AssetEntry instances. Since they already have their own renderer, they can appear in the Asset Publisher with no additional changes. If you create a provider for a custom class, you must also render it.

1. Create a module named asset-entry-info-list-provider.

2. Create a package inside the module named com.liferay.docs.info.provider.

3. Inside the package, create a class named AssetEntryInfoListProvider that implements InfoListProvider and registers it as a component:

   @Component(service = InfoListProvider.class)
     public class AssetEntryInfoListProvider implements InfoListProvider<AssetEntry> {
   
   }
   

4. Next, add the necessary @Reference that you need for the logic of retrieving assets to the bottom of the class.

   @Reference
   AssetEntryLocalService _assetEntryLocalService;
   

5. Then implement getInfoList which returns just the list.

   @Override
   public List<AssetEntry> getInfoList(
    InfoListProviderContext infoListProviderContext) {
   
    return _assetEntryLocalService.getTopViewedEntries(
       new String[0], false, 0, 20);
   }
   

   Descending order and a maximum of 20 items to return is hardcoded.

6. Now implement the second method, which provides greater control over how items are returned to the provider.

   @Override
   public List<AssetEntry> getInfoList(
     InfoListProviderContext infoListProviderContext, Pagination pagination,
     Sort sort) {
   
     return _assetEntryLocalService.getTopViewedEntries(
        new String[0], !sort.isReverse(), pagination.getStart(),
        pagination.getEnd());
   }
   

7. Provide a method to get a full count of info list items.

   @Override
   public int getInfoListCount(
   InfoListProviderContext infoListProviderContext) {
   
       Company company = infoListProviderContext.getCompany();
   
       return _assetEntryLocalService.getCompanyEntriesCount(
       company.getCompanyId());
   }
   

8. Finally, add a method that provides a display label for the list.

   @Override
   public String getLabel(Locale locale) {
    return "Most Viewed Content";
    }
   

The completed class should look like this:

@Component(service = InfoListProvider.class)
  public class AssetEntryInfoListProvider implements InfoListProvider<AssetEntry> {

           @Override
           public List<AssetEntry> getInfoList(
             InfoListProviderContext infoListProviderContext) {

             return _assetEntryLocalService.getTopViewedEntries(
                new String[0], false, 0, 20);
           }

         @Override
         public List<AssetEntry> getInfoList(
           InfoListProviderContext infoListProviderContext, Pagination pagination,
           Sort sort) {

           return _assetEntryLocalService.getTopViewedEntries(
              new String[0], !sort.isReverse(), pagination.getStart(),
              pagination.getEnd());
         }

         @Override
         public int getInfoListCount(
         InfoListProviderContext infoListProviderContext) {

             Company company = infoListProviderContext.getCompany();

             return _assetEntryLocalService.getCompanyEntriesCount(
             company.getCompanyId());
         }

           @Override
           public String getLabel(Locale locale) {
             return "Most Viewed Content";
             }

@Reference
AssetEntryLocalService _assetEntryLocalService;
}

This class is now ready to go! If you deploy it, it shows the “Most Viewed Content” in any Asset Publisher.

Next steps

This example is pretty simplistic and probably not useful in real world cases. To begin with, you may want to scope the search to the current site. You can also add more advanced filter criteria or provide a configuration for the provider using Liferay’s configuration framework.

As mentioned, it is also possible to implement providers for custom types. The following code shows a partial example of a provider for a custom MyOrder class:

@Component(service = InfoListProvider.class)
public class MyOrderProvider implements InfoListProvider<MyOrder> {

    @Override
    public List<MyOrder> getInfoList(
        InfoListProviderContext infoListProviderContext, Pagination pagination,
        Sort sort) {

        return _myOrderLocalService.getOrders(
            [...], !sort.isReverse(), pagination.getStart(),
            pagination.getEnd());
        }

    [..]

    @Reference
    MyOrderLocalService _myOrderLocalService;