DATAMONGO-1813 - Polishing.

Add since tag. Add non-null guard. Refactor conditional resource mapping to Optional. Apply code formatter.

Optimize array construction from List.

Original pull request: #543.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/GridFsOperations.java

@@ -160,8 +160,10 @@ public interface GridFsOperations extends ResourcePatternResolver {
 
 	/**
 	 * Returns the {@link GridFsResource} for a {@link com.mongodb.client.gridfs.model.GridFSFile}.
+	 *
 	 * @param file must not be {@literal null}.
 	 * @return the resource for the file.
+	 * @since 2.1
 	 */
 	GridFsResource getResource(com.mongodb.client.gridfs.model.GridFSFile file);
 

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/gridfs/GridFsTemplate.java

@@ -227,9 +227,7 @@ public class GridFsTemplate implements GridFsOperations, ResourcePatternResolver
 	 * @see org.springframework.core.io.ResourceLoader#getResource(java.lang.String)
 	 */
 	public GridFsResource getResource(String location) {
-
-		GridFSFile file = findOne(query(whereFilename().is(location)));
-		return file != null ? getResource(file) : null;
+		return Optional.ofNullable(findOne(query(whereFilename().is(location)))).map(this::getResource).orElse(null);
 	}
 
 	/*
@@ -238,6 +236,8 @@ public class GridFsTemplate implements GridFsOperations, ResourcePatternResolver
 	 */
 	public GridFsResource getResource(GridFSFile file) {
 
+		Assert.notNull(file, "GridFSFile must not be null!");
+
 		return new GridFsResource(file, getGridFs().openDownloadStream(file.getFilename()));
 	}
 
@@ -256,13 +256,13 @@ public class GridFsTemplate implements GridFsOperations, ResourcePatternResolver
 		if (path.isPattern()) {
 
 			GridFSFindIterable files = find(query(whereFilename().regex(path.toRegex())));
-			List<GridFsResource> resources = new ArrayList<GridFsResource>();
+			List<GridFsResource> resources = new ArrayList<>();
 
 			for (GridFSFile file : files) {
 				resources.add(new GridFsResource(file, getGridFs().openDownloadStream(file.getFilename())));
 			}
 
-			return resources.toArray(new GridFsResource[resources.size()]);
+			return resources.toArray(new GridFsResource[0]);
 		}
 
 		return new GridFsResource[] { getResource(locationPattern) };

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/gridfs/GridFsTemplateIntegrationTests.java

@@ -24,7 +24,6 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
-import org.assertj.core.api.Assertions;
 import org.bson.BsonObjectId;
 import org.bson.Document;
 import org.bson.types.ObjectId;
@@ -233,7 +232,6 @@ public class GridFsTemplateIntegrationTests {
 		Document metadata = new Document("key", "value");
 		ObjectId reference = operations.store(resource.getInputStream(), "foobar", metadata);
 
-		List<com.mongodb.client.gridfs.model.GridFSFile> files = new ArrayList<com.mongodb.client.gridfs.model.GridFSFile>();
 		GridFSFile file = operations.findOne(query(whereMetaData("key").is("value")));
 		GridFsResource result = operations.getResource(file);