refactor: promote not found to an inner class alongside Found

Changes `Success` to `Found` and promotes the "item not found" case to
an inner class alongside `Found`. This way, `Found::value` is no
longer an Optional. This removes part a layer of the decision tree
when unpacking a found item.

momento-sdk/src/intTest/java/momento/sdk/storage/DataTests.java

@@ -48,8 +48,8 @@ void getReturnsValueAsStringAfterPut() {
 
     // Successful Get
     final GetResponse getResponse = client.get(storeName, key).join();
-    assertThat(getResponse).isInstanceOf(GetResponse.Success.class);
-    assertThat(getResponse.success().get().value().get().getString().get()).isEqualTo(value);
+    assertThat(getResponse).isInstanceOf(GetResponse.Found.class);
+    assertThat(getResponse.found().get().value().getString().get()).isEqualTo(value);
   }
 
   @Test
@@ -63,9 +63,8 @@ void getReturnsValueAsByteArrayAfterPut() {
 
     // Successful Get
     final GetResponse getResponse = client.get(storeName, key).join();
-    assertThat(getResponse).isInstanceOf(GetResponse.Success.class);
-    assertThat(getResponse.success().get().value().get().getByteArray().get())
-        .isEqualTo(value.getBytes());
+    assertThat(getResponse).isInstanceOf(GetResponse.Found.class);
+    assertThat(getResponse.found().get().value().getByteArray().get()).isEqualTo(value.getBytes());
   }
 
   @Test
@@ -79,8 +78,8 @@ void getReturnsValueAsLongAfterPut() {
 
     // Successful Get
     final GetResponse getResponse = client.get(storeName, key).join();
-    assertThat(getResponse).isInstanceOf(GetResponse.Success.class);
-    assertThat(getResponse.success().get().value().get().getLong().get()).isEqualTo(value);
+    assertThat(getResponse).isInstanceOf(GetResponse.Found.class);
+    assertThat(getResponse.found().get().value().getLong().get()).isEqualTo(value);
   }
 
   @Test
@@ -94,16 +93,17 @@ void getReturnsValueAsDoubleAfterPut() {
 
     // Successful Get
     final GetResponse getResponse = client.get(storeName, key).join();
-    assertThat(getResponse).isInstanceOf(GetResponse.Success.class);
-    assertThat(getResponse.success().get().value().get().getDouble().get()).isEqualTo(value);
+    assertThat(getResponse).isInstanceOf(GetResponse.Found.class);
+    assertThat(getResponse.found().get().value().getDouble().get()).isEqualTo(value);
   }
 
   @Test
   void storeKeyNotFound() {
     // Get key that was not set
     final GetResponse response = client.get(storeName, randomString("key")).join();
-    assertThat(response).isInstanceOf(GetResponse.Success.class);
-    assert !response.success().get().value().isPresent();
+    assertThat(response).isInstanceOf(GetResponse.NotFound.class);
+    assert !response.found().isPresent();
+    assert response instanceof GetResponse.NotFound;
   }
 
   @Test
@@ -125,8 +125,8 @@ public void allowEmptyKeyValuesOnGet() throws Exception {
     final String emptyValue = "";
     client.put(storeName, emptyKey, emptyValue).get();
     final GetResponse response = client.get(storeName, emptyKey).get();
-    assertThat(response).isInstanceOf(GetResponse.Success.class);
-    assert response.success().get().value().get().getString().get().isEmpty();
+    assertThat(response).isInstanceOf(GetResponse.Found.class);
+    assert response.found().get().value().getString().get().isEmpty();
   }
 
   @Test
@@ -136,14 +136,15 @@ public void deleteHappyPath() throws Exception {
 
     client.put(storeName, key, value).get();
     final GetResponse getResponse = client.get(storeName, key).get();
-    assertThat(getResponse).isInstanceOf(GetResponse.Success.class);
-    assertThat(getResponse.success().get().value().get().getString().get()).isEqualTo(value);
+    assertThat(getResponse).isInstanceOf(GetResponse.Found.class);
+    assertThat(getResponse.found().get().value().getString().get()).isEqualTo(value);
 
     final DeleteResponse deleteResponse = client.delete(storeName, key).get();
     assertThat(deleteResponse).isInstanceOf(DeleteResponse.Success.class);
 
     final GetResponse getAfterDeleteResponse = client.get(storeName, key).get();
-    assert !getAfterDeleteResponse.success().get().value().isPresent();
+    assert !getAfterDeleteResponse.found().isPresent();
+    assert getAfterDeleteResponse instanceof GetResponse.NotFound;
   }
 
   @Test

momento-sdk/src/main/java/momento/sdk/StorageDataClient.java

@@ -136,16 +136,16 @@ public void onSuccess(_StoreGetResponse rsp) {
             _StoreValue value = rsp.getValue();
             switch (value.getValueCase()) {
               case BYTES_VALUE:
-                returnFuture.complete(GetResponse.Success.of(value.getBytesValue().toByteArray()));
+                returnFuture.complete(GetResponse.Found.of(value.getBytesValue().toByteArray()));
                 break;
               case STRING_VALUE:
-                returnFuture.complete(GetResponse.Success.of(value.getStringValue()));
+                returnFuture.complete(GetResponse.Found.of(value.getStringValue()));
                 break;
               case INTEGER_VALUE:
-                returnFuture.complete(GetResponse.Success.of(value.getIntegerValue()));
+                returnFuture.complete(GetResponse.Found.of(value.getIntegerValue()));
                 break;
               case DOUBLE_VALUE:
-                returnFuture.complete(GetResponse.Success.of(value.getDoubleValue()));
+                returnFuture.complete(GetResponse.Found.of(value.getDoubleValue()));
                 break;
               case VALUE_NOT_SET:
                 returnFuture.complete(
@@ -159,7 +159,7 @@ public void onSuccess(_StoreGetResponse rsp) {
           public void onFailure(@Nonnull Throwable e) {
             final SdkException sdkException = CacheServiceExceptionMapper.convert(e, metadata);
             if (sdkException instanceof momento.sdk.exceptions.StoreItemNotFoundException) {
-              returnFuture.complete(GetResponse.Success.of());
+              returnFuture.complete(new GetResponse.NotFound());
             } else {
               returnFuture.complete(new GetResponse.Error(CacheServiceExceptionMapper.convert(e)));
             }

momento-sdk/src/main/java/momento/sdk/responses/storage/GetResponse.java

@@ -2,21 +2,21 @@
 
 import java.util.Optional;
 import momento.sdk.exceptions.SdkException;
+import momento.sdk.internal.StringHelpers;
 
 /**
  * Response for a get operation.
  *
- * <p>The response can be either a {@link Success} or an {@link Error}.
+ * <p>The response can be either a {@link Found}, {@link NotFound}, or an {@link Error}.
  *
- * <p>To shortcut access to the success response, use {@link #success()}. If the operation was
- * successful, the response will be an optional of {@link Success}, otherwise it will be an empty
- * optional.
+ * <p>To shortcut access to found response, use {@link #found()}. If the operation was successful
+ * but the key was not found, the response will be an empty optional. If the operation failed, the
+ * response will be an empty optional.
  *
  * <p>To handle the response otherwise, use pattern matching or an instanceof to check if the
- * response is a {@link Success} or an {@link Error}.
+ * response is a {@link Found}, {@link NotFound}, or an {@link Error}.
  *
- * <p>Upon a success, the value can be retrieved with {@link Success#value()}. If the value was
- * found in the store, it will be present, otherwise it will be empty.
+ * <p>Upon a found response, the value can be retrieved with {@link Found#value()}.
  */
 public interface GetResponse {
   /**
@@ -27,7 +27,7 @@ public interface GetResponse {
    *
    * @return The success response, or an empty optional if the operation failed.
    */
-  Optional<Success> success();
+  Optional<Found> found();
 
   /**
    * A successful get operation.
@@ -38,50 +38,60 @@ public interface GetResponse {
    * <p>Use the appropriate type-based accessor on the value to retrieve the value in its
    * corresponding type.
    */
-  class Success implements GetResponse {
-    private final Optional<StorageValue> value;
+  class Found implements GetResponse {
+    private final StorageValue value;
 
-    private Success(Optional<StorageValue> value) {
+    private Found(StorageValue value) {
       this.value = value;
     }
 
-    public static Success of() {
-      return new Success(Optional.empty());
+    public static Found of(byte[] value) {
+      return new Found(StorageValue.of(value));
     }
 
-    public static Success of(byte[] value) {
-      return new Success(Optional.of(StorageValue.of(value)));
+    public static Found of(String value) {
+      return new Found(StorageValue.of(value));
     }
 
-    public static Success of(String value) {
-      return new Success(Optional.of(StorageValue.of(value)));
+    public static Found of(long value) {
+      return new Found(StorageValue.of(value));
     }
 
-    public static Success of(long value) {
-      return new Success(Optional.of(StorageValue.of(value)));
-    }
-
-    public static Success of(double value) {
-      return new Success(Optional.of(StorageValue.of(value)));
+    public static Found of(double value) {
+      return new Found(StorageValue.of(value));
     }
 
     /**
      * Returns the value if it exists, or an empty optional if the value does not exist.
      *
      * @return The value, or an empty optional if the value does not exist.
      */
-    public Optional<StorageValue> value() {
+    public StorageValue value() {
       return value;
     }
 
     @Override
-    public Optional<Success> success() {
+    public Optional<Found> found() {
       return Optional.of(this);
     }
 
     @Override
     public String toString() {
-      return "GetResponse.Success{value=" + value + "}";
+      return "GetResponse.Found{value=" + value + "}";
+    }
+  }
+
+  class NotFound implements GetResponse {
+    public NotFound() {}
+
+    @Override
+    public Optional<Found> found() {
+      return Optional.empty();
+    }
+
+    @Override
+    public String toString() {
+      return StringHelpers.emptyToString("GetResponse.NotFound");
     }
   }
 
@@ -102,7 +112,7 @@ public Error(SdkException cause) {
     }
 
     @Override
-    public Optional<Success> success() {
+    public Optional<Found> found() {
       return Optional.empty();
     }
 

momento-sdk/src/test/java/momento/sdk/responses/storage/GetResponseTest.java

@@ -8,57 +8,56 @@
 
 public class GetResponseTest {
   @Test
-  public void testGetResponseSuccessWorksOnTheRightType() {
-    GetResponse.Success response = GetResponse.Success.of(new byte[] {0, 1, 2, 3});
-    assert response.value().get().getByteArray().get().length == 4;
-    assert !response.value().get().getString().isPresent();
-    assert !response.value().get().getLong().isPresent();
-    assert !response.value().get().getDouble().isPresent();
-
-    response = GetResponse.Success.of("string");
-    assert !response.value().get().getByteArray().isPresent();
-    assert response.value().get().getString().get().equals("string");
-    assert !response.value().get().getLong().isPresent();
-    assert !response.value().get().getDouble().isPresent();
-
-    response = GetResponse.Success.of(42L);
-    assert !response.value().get().getByteArray().isPresent();
-    assert !response.value().get().getString().isPresent();
-    assert response.value().get().getLong().get() == 42L;
-    assert !response.value().get().getDouble().isPresent();
-
-    response = GetResponse.Success.of(3.14);
-    assert !response.value().get().getByteArray().isPresent();
-    assert !response.value().get().getString().isPresent();
-    assert !response.value().get().getLong().isPresent();
-    assert response.value().get().getDouble().get() == 3.14;
+  public void testGetResponseFoundWorksOnTheRightType() {
+    GetResponse.Found response = GetResponse.Found.of(new byte[] {0, 1, 2, 3});
+    assert response.value().getByteArray().get().length == 4;
+    assert !response.value().getString().isPresent();
+    assert !response.value().getLong().isPresent();
+    assert !response.value().getDouble().isPresent();
+
+    response = GetResponse.Found.of("string");
+    assert !response.value().getByteArray().isPresent();
+    assert response.value().getString().get().equals("string");
+    assert !response.value().getLong().isPresent();
+    assert !response.value().getDouble().isPresent();
+
+    response = GetResponse.Found.of(42L);
+    assert !response.value().getByteArray().isPresent();
+    assert !response.value().getString().isPresent();
+    assert response.value().getLong().get() == 42L;
+    assert !response.value().getDouble().isPresent();
+
+    response = GetResponse.Found.of(3.14);
+    assert !response.value().getByteArray().isPresent();
+    assert !response.value().getString().isPresent();
+    assert !response.value().getLong().isPresent();
+    assert response.value().getDouble().get() == 3.14;
   }
 
   @Test
   public void testConvenienceMethodsOnGetResponse() {
-    GetResponse.Success response = GetResponse.Success.of(new byte[] {0, 1, 2, 3});
-    assert response.success().isPresent();
-    assert response.success().get().value().get().getByteArray().get().length == 4;
+    GetResponse.Found response = GetResponse.Found.of(new byte[] {0, 1, 2, 3});
+    assert response.found().isPresent();
+    assert response.found().get().value().getByteArray().get().length == 4;
 
-    response = GetResponse.Success.of("string");
-    assert response.success().isPresent();
-    assert response.success().get().value().get().getString().get() == "string";
+    response = GetResponse.Found.of("string");
+    assert response.found().isPresent();
+    assert response.found().get().value().getString().get() == "string";
 
-    response = GetResponse.Success.of(42L);
-    assert response.success().isPresent();
-    assert response.success().get().value().get().getLong().get() == 42L;
+    response = GetResponse.Found.of(42L);
+    assert response.found().isPresent();
+    assert response.found().get().value().getLong().get() == 42L;
 
-    response = GetResponse.Success.of(3.14);
-    assert response.success().isPresent();
-    assert response.success().get().value().get().getDouble().get() == 3.14;
+    response = GetResponse.Found.of(3.14);
+    assert response.found().isPresent();
+    assert response.found().get().value().getDouble().get() == 3.14;
 
-    // TODO distinguish store not found from key not found
     GetResponse.Error error =
         new GetResponse.Error(
             new StoreNotFoundException(
                 new Exception(),
                 new MomentoTransportErrorDetails(
                     new MomentoGrpcErrorDetails(Status.Code.NOT_FOUND, "not found"))));
-    assert !error.success().isPresent();
+    assert !error.found().isPresent();
   }
 }