Polishing.

Reformat code, add contract annotation.

See #3452
Original pull request: #3454

Author: mp911de

src/main/java/org/springframework/data/web/SlicedResourcesAssembler.java

@@ -39,6 +39,7 @@
 import org.springframework.hateoas.server.RepresentationModelAssembler;
 import org.springframework.hateoas.server.core.EmbeddedWrapper;
 import org.springframework.hateoas.server.core.EmbeddedWrappers;
+import org.springframework.lang.CheckReturnValue;
 import org.springframework.util.Assert;
 import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
 import org.springframework.web.util.UriComponents;
@@ -100,6 +101,7 @@ public void setForceFirstRel(boolean forceFirstRel) {
 	 * @return will never be {@literal null}.
 	 * @since 3.1
 	 */
+	@CheckReturnValue
 	public SlicedResourcesAssembler<T> withParameter(@Nullable MethodParameter parameter) {
 		return new SlicedResourcesAssembler<>(pageableResolver, baseUri, parameter);
 	}
@@ -116,7 +118,7 @@ public SlicedModel<EntityModel<T>> toModel(Slice<T> entity) {
 	 *
 	 * @param slice must not be {@literal null}.
 	 * @param selfLink must not be {@literal null}.
-	 * @return
+	 * @return a {@link SlicedModel}.
 	 */
 	public SlicedModel<EntityModel<T>> toModel(Slice<T> slice, Link selfLink) {
 		return toModel(slice, EntityModel::of, selfLink);
@@ -128,7 +130,7 @@ public SlicedModel<EntityModel<T>> toModel(Slice<T> slice, Link selfLink) {
 	 *
 	 * @param slice must not be {@literal null}.
 	 * @param assembler must not be {@literal null}.
-	 * @return
+	 * @return a {@link SlicedModel}.
 	 */
 	public <R extends RepresentationModel<?>> SlicedModel<R> toModel(Slice<T> slice,
 			RepresentationModelAssembler<T, R> assembler) {
@@ -143,11 +145,13 @@ public <R extends RepresentationModel<?>> SlicedModel<R> toModel(Slice<T> slice,
 	 * @param slice must not be {@literal null}.
 	 * @param assembler must not be {@literal null}.
 	 * @param link must not be {@literal null}.
-	 * @return a {@link SlicedModel} must not be {@literal null}.
+	 * @return a {@link SlicedModel}.
 	 */
 	public <R extends RepresentationModel<?>> SlicedModel<R> toModel(Slice<T> slice,
 			RepresentationModelAssembler<T, R> assembler, Link link) {
+
 		Assert.notNull(link, "Link must not be null");
+
 		return createModel(slice, assembler, link);
 	}
 
@@ -156,7 +160,7 @@ public <R extends RepresentationModel<?>> SlicedModel<R> toModel(Slice<T> slice,
 	 *
 	 * @param slice must not be {@literal null}, content must be empty.
 	 * @param type must not be {@literal null}.
-	 * @return
+	 * @return an empty {@link SlicedModel}.
 	 */
 	public SlicedModel<?> toEmptyModel(Slice<?> slice, Class<?> type) {
 		return toEmptyModel(slice, type, (Link) null);
@@ -168,7 +172,7 @@ public SlicedModel<?> toEmptyModel(Slice<?> slice, Class<?> type) {
 	 * @param slice must not be {@literal null}, content must be empty.
 	 * @param type must not be {@literal null}.
 	 * @param link can be {@literal null}.
-	 * @return a {@link SlicedModel} must not be {@literal null}.
+	 * @return an empty {@link SlicedModel}.
 	 */
 	public SlicedModel<?> toEmptyModel(Slice<?> slice, Class<?> type, @Nullable Link link) {
 
@@ -187,7 +191,6 @@ public SlicedModel<?> toEmptyModel(Slice<?> slice, Class<?> type, @Nullable Link
 
 	@Deprecated
 	public SlicedModel<?> toEmptyModel(Slice<?> slice, Class<?> type, Optional<Link> link) {
-		Assert.notNull(link, "Link must not be null");
 		return toEmptyModel(slice, type, link.orElse(null));
 	}
 
@@ -201,6 +204,7 @@ public SlicedModel<?> toEmptyModel(Slice<?> slice, Class<?> type, Optional<Link>
 	 */
 	protected <R extends RepresentationModel<?>, S> SlicedModel<R> createSlicedModel(List<R> resources,
 			SliceMetadata metadata, Slice<S> slice) {
+
 		Assert.notNull(resources, "Content resources must not be null");
 		Assert.notNull(metadata, "SliceMetadata must not be null");
 		Assert.notNull(slice, "Slice must not be null");
@@ -210,6 +214,7 @@ protected <R extends RepresentationModel<?>, S> SlicedModel<R> createSlicedModel
 
 	private <S, R extends RepresentationModel<?>> SlicedModel<R> createModel(Slice<S> slice,
 			RepresentationModelAssembler<S, R> assembler, @Nullable Link link) {
+
 		Assert.notNull(slice, "Slice must not be null");
 		Assert.notNull(assembler, "ResourceAssembler must not be null");
 
@@ -227,7 +232,6 @@ private <S, R extends RepresentationModel<?>> SlicedModel<R> createModel(Slice<S
 	private <R> SlicedModel<R> addPaginationLinks(SlicedModel<R> resources, Slice<?> slice, @Nullable Link link) {
 
 		UriTemplate base = getUriTemplate(link);
-
 		boolean isNavigable = slice.hasPrevious() || slice.hasNext();
 
 		if (isNavigable || forceFirstRel) {

src/test/java/org/springframework/data/web/SlicedResourcesAssemblerUnitTest.java

@@ -22,10 +22,11 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
-
 import java.util.Optional;
+
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+
 import org.springframework.data.domain.AbstractPageRequest;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
@@ -46,7 +47,6 @@
  *
  * @author Michael Schout
  * @author Oliver Drotbohm
- * @since 3.1
  */
 class SlicedResourcesAssemblerUnitTest {