Android/app/src/main/java/com/moiseum/wolnelektury/base/DataProvider.java

   1 package com.moiseum.wolnelektury.base;
   2
   3 import android.util.Log;
   4
   5 import com.moiseum.wolnelektury.connection.RestClientCallback;
   6
   7 import javax.annotation.Nullable;
   8
   9 import retrofit2.Call;
  10
  11 /**
  12  * @author golonkos.
  13  */
  14
  15 public abstract class DataProvider<T, S> extends RestClientCallback<T, S> {
  16
  17         private final static String TAG = DataProvider.class.getSimpleName();
  18
  19         protected DataObserver<T> dataObserver;
  20         protected String lastKeySlug = null;
  21         private Call<T> call;
  22
  23         public DataProvider() {
  24         }
  25
  26         public void setDataObserver(DataObserver<T> dataObserver) {
  27                 this.dataObserver = dataObserver;
  28         }
  29
  30         @Override
  31         public void onSuccess(T data) {
  32                 if (dataObserver != null) {
  33                         dataObserver.onLoadSuccess(data);
  34                 }
  35         }
  36
  37         @Override
  38         public void onFailure(Exception e) {
  39                 Log.e(TAG, "Failed to load data", e);
  40                 if (dataObserver != null) {
  41                         dataObserver.onLoadFailed(e);
  42                 }
  43         }
  44
  45         @Override
  46         public void onCancel() {
  47                 //nop
  48         }
  49
  50         /**
  51          * Invoked in order to load data.
  52          * @param lastKey Last book slug for pagination. Can be null if there is no pagination.
  53          */
  54         public void load(@Nullable String lastKey) {
  55                 cancel();
  56                 lastKeySlug = lastKey;
  57                 call = WLApplication.getInstance().getRestClient().call(this, getServiceClass());
  58                 if (dataObserver != null) {
  59                         dataObserver.onLoadStarted();
  60                 }
  61         }
  62
  63         public void cancel() {
  64                 if (call != null) {
  65                         call.cancel();
  66                         call = null;
  67                 }
  68         }
  69
  70         public void release() {
  71                 dataObserver = null;
  72         }
  73
  74         protected abstract Class<S> getServiceClass();
  75 }