make batch gets return null as well on 404

Author: aozarov

src/main/java/com/google/gcloud/storage/BatchResponse.java

@@ -36,10 +36,12 @@ public class BatchResponse implements Serializable {
   public static class Result<T extends Serializable> implements Serializable {
 
     private static final long serialVersionUID = -1946539570170529094L;
+    private static final Result EMPTY = new BatchResponse.Result(null);
 
     private final T value;
     private final StorageServiceException exception;
 
+
     Result(T value) {
       this.value = value;
       this.exception = null;
@@ -50,13 +52,15 @@ public static class Result<T extends Serializable> implements Serializable {
       this.value = null;
     }
 
-
     /**
      * Returns the result.
      *
      * @throws StorageServiceException if failed
      */
     public T result() throws StorageServiceException {
+      if (failed()) {
+        throw failure();
+      }
       return value;
     }
 
@@ -76,7 +80,15 @@ public boolean failed() {
 
     @Override
     public String toString() {
-      return MoreObjects.firstNonNull(value, exception).toString();
+      return MoreObjects.toStringHelper(this)
+          .add("value", value)
+          .add("exception", exception)
+          .toString();
+    }
+
+    @SuppressWarnings("unchecked")
+    static <T extends Serializable> Result<T> empty() {
+      return EMPTY;
     }
   }
 

src/main/java/com/google/gcloud/storage/StorageServiceImpl.java

@@ -37,6 +37,8 @@
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+import com.google.common.primitives.Ints;
 import com.google.gcloud.BaseService;
 import com.google.gcloud.ExceptionHandler;
 import com.google.gcloud.ExceptionHandler.Interceptor;
@@ -52,6 +54,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.Callable;
 
 final class StorageServiceImpl extends BaseService<StorageServiceOptions> implements StorageService {
@@ -325,20 +328,28 @@ public BatchResponse apply(BatchRequest batchRequest) {
     List<BatchResponse.Result<Blob>> updates = transformBatchResult(
         toUpdate, response.updates, Blob.FROM_PB_FUNCTION);
     List<BatchResponse.Result<Blob>> gets = transformBatchResult(
-        toGet, response.gets, Blob.FROM_PB_FUNCTION);
+        toGet, response.gets, Blob.FROM_PB_FUNCTION, 404);
     return new BatchResponse(deletes, updates, gets);
   }
 
   private <I, O extends Serializable> List<BatchResponse.Result<O>> transformBatchResult(
       Iterable<Tuple<StorageObject, Map<StorageRpc.Option, ?>>> request,
-      Map<StorageObject, Tuple<I, StorageServiceException>> results, Function<I, O> transform) {
+      Map<StorageObject, Tuple<I, StorageServiceException>> results, Function<I, O> transform,
+      int... nullOnErrorCodes) {
+    Set nullOnErrorCodesSet = Sets.newHashSet(Ints.asList(nullOnErrorCodes));
     List<BatchResponse.Result<O>> response = Lists.newArrayListWithCapacity(results.size());
     for (Tuple<StorageObject, ?> tuple : request) {
       Tuple<I, StorageServiceException> result = results.get(tuple.x());
       if (result.x() != null) {
         response.add(new BatchResponse.Result<>(transform.apply(result.x())));
       } else {
-        response.add(new BatchResponse.Result<O>(result.y()));
+        StorageServiceException exception = result.y();
+        if (nullOnErrorCodesSet.contains(exception.code())) {
+          //noinspection unchecked
+          response.add(BatchResponse.Result.<O>empty());
+        } else {
+          response.add(new BatchResponse.Result<O>(result.y()));
+        }
       }
     }
     return response;