Implement datastore Blob to byte[] conversion on read

spring-cloud-gcp-data-datastore/src/main/java/com/google/cloud/spring/data/datastore/core/convert/TwoStepsConversions.java

@@ -120,7 +120,7 @@ public <T> T convertOnRead(Object val, Class targetCollectionType, Class targetC
 	public <T> T convertOnRead(Object val, EmbeddedType embeddedType, TypeInformation targetTypeInformation) {
 		TypeInformation componentTypeInformation;
 		Class collectionType = null;
-		if (targetTypeInformation.isCollectionLike()) {
+		if (ValueUtil.isCollectionLike(targetTypeInformation.getType())) {
 			componentTypeInformation = targetTypeInformation.getComponentType();
 			collectionType = targetTypeInformation.getType();
 		}
@@ -155,6 +155,7 @@ private <T> T convertOnRead(Object val, EmbeddedType embeddedType,
 
 		if (ValueUtil.isCollectionLike(val.getClass())
 				&& targetCollectionType != null && targetComponentType != null) {
+			// Convert collection.
 			try {
 				List elements;
 				if (val.getClass().isArray()) {
@@ -175,6 +176,7 @@ private <T> T convertOnRead(Object val, EmbeddedType embeddedType,
 				throw new DatastoreDataException("Unable process elements of a collection", ex);
 			}
 		}
+		// Convert single value.
 		return (T) readConverter.apply(val, targetComponentType);
 	}
 

spring-cloud-gcp-data-datastore/src/test/java/com/google/cloud/spring/data/datastore/core/convert/DefaultDatastoreEntityConverterTests.java

@@ -103,7 +103,8 @@ public void setUp() {
 	public void readTest() {
 		byte[] bytes = { 1, 2, 3 };
 		Key otherKey = Key.newBuilder("testproject", "test_kind", "test_name").build();
-		Entity entity = getEntityBuilder()
+		// Datastore Entity from the backend / client library.
+		Entity datastoreEntity = getEntityBuilder()
 				.set("durationField", "PT24H")
 				.set("stringField", "string value")
 				.set("boolField", true)
@@ -116,21 +117,36 @@ public void readTest() {
 				.set("enumField", "WHITE")
 				.set("keyField", otherKey)
 				.build();
-		TestDatastoreItem item = ENTITY_CONVERTER.read(TestDatastoreItem.class, entity);
-
-		assertThat(item.getDurationField()).as("validate duration field").isEqualTo(Duration.ofDays(1));
-		assertThat(item.getStringField()).as("validate string field").isEqualTo("string value");
-		assertThat(item.getBoolField()).as("validate boolean field").isTrue();
-		assertThat(item.getDoubleField()).as("validate double field").isEqualTo(3.1415D);
-		assertThat(item.getLongField()).as("validate long field").isEqualTo(123L);
-		assertThat(item.getLatLngField()).as("validate latLng field")
+		// Plain Java Object that the user expects to operate on.
+		TestDatastoreItem userItem = ENTITY_CONVERTER.read(TestDatastoreItem.class, datastoreEntity);
+
+		assertThat(userItem.getDurationField()).as("validate duration field").isEqualTo(Duration.ofDays(1));
+		assertThat(userItem.getStringField()).as("validate string field").isEqualTo("string value");
+		assertThat(userItem.getBoolField()).as("validate boolean field").isTrue();
+		assertThat(userItem.getDoubleField()).as("validate double field").isEqualTo(3.1415D);
+		assertThat(userItem.getLongField()).as("validate long field").isEqualTo(123L);
+		assertThat(userItem.getLatLngField()).as("validate latLng field")
 				.isEqualTo(LatLng.of(10, 20));
-		assertThat(item.getTimestampField()).as("validate timestamp field")
+		assertThat(userItem.getTimestampField()).as("validate timestamp field")
 				.isEqualTo(Timestamp.ofTimeSecondsAndNanos(30, 40));
-		assertThat(item.getBlobField()).as("validate blob field").isEqualTo(Blob.copyFrom(bytes));
-		assertThat(item.getIntField()).as("validate int field").isEqualTo(99);
-		assertThat(item.getEnumField()).as("validate enum field").isEqualTo(TestDatastoreItem.Color.WHITE);
-		assertThat(item.getKeyField()).as("validate key field").isEqualTo(otherKey);
+		assertThat(userItem.getBlobField()).as("validate blob field").isEqualTo(Blob.copyFrom(bytes));
+		assertThat(userItem.getIntField()).as("validate int field").isEqualTo(99);
+		assertThat(userItem.getEnumField()).as("validate enum field").isEqualTo(TestDatastoreItem.Color.WHITE);
+		assertThat(userItem.getKeyField()).as("validate key field").isEqualTo(otherKey);
+	}
+
+	@Test
+	public void readTestByteArray() {
+		byte[] bytes = { 1, 2, 3 };
+
+		// Datastore Entity from the backend / client library.
+		Entity datastoreEntity = getEntityBuilder()
+				.set("byteArrayField", Blob.copyFrom(bytes))
+				.build();
+		// Plain Java Object that the user expects to operate on.
+		TestDatastoreItem userItem = ENTITY_CONVERTER.read(TestDatastoreItem.class, datastoreEntity);
+
+		assertThat(userItem.getByteArrayField()).as("validate byte array field").isEqualTo(bytes);
 	}
 
 	@Test

spring-cloud-gcp-samples/spring-cloud-gcp-data-datastore-sample/src/main/java/com/example/DatastoreRepositoryExample.java

@@ -16,6 +16,7 @@
 
 package com.example;
 
+import java.nio.charset.StandardCharsets;
 import java.time.LocalDate;
 import java.time.Month;
 import java.util.Arrays;
@@ -69,6 +70,7 @@ public CommandLineRunner commandLineRunner() {
 							new Album("b", LocalDate.of(2018, Month.FEBRUARY, 12)))));
 			Singer richardRoe = new Singer("singer3", "Richard", "Roe",
 					new HashSet<>(Arrays.asList(new Album("c", LocalDate.of(2000, Month.AUGUST, 31)))));
+			richardRoe.setMessage("Hello, dear fans!".getBytes(StandardCharsets.UTF_8));
 
 			this.singerRepository.saveAll(Arrays.asList(janeDoe, richardRoe));
 

spring-cloud-gcp-samples/spring-cloud-gcp-data-datastore-sample/src/main/java/com/example/Singer.java

@@ -64,6 +64,8 @@ public class Singer {
 
 	private Set<Album> albums;
 
+	private byte[] message;
+
 	public Singer() {
 	}
 
@@ -130,6 +132,14 @@ public void setAlbums(Set<Album> albums) {
 		this.albums = albums;
 	}
 
+	public byte[] getMessage() {
+		return message;
+	}
+
+	public void setMessage(byte[] message) {
+		this.message = message;
+	}
+
 	@Override
 	public boolean equals(Object o) {
 		if (this == o) {
@@ -162,6 +172,7 @@ public String toString() {
 				+ ((this.personalInstruments == null) ? ""
 						: Strings.join(this.personalInstruments.stream()
 								.map(x -> x.getType()).collect(Collectors.toList()), ','))
+				+ ((this.message == null) ? "" : ", Message: " + new String(message))
 				+ '}';
 	}