DATACMNS-867 - Removed handling of null Pageables.

Pageable now exposes a dedicated null-object representing the absence of pagination so that all places that previously handled null values can now rather be more relaxed and assume that a non-null value is given.

src/main/java/org/springframework/data/domain/Pageable.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2013 the original author or authors.
+ * Copyright 2008-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,8 @@
  */
 package org.springframework.data.domain;
 
+import java.util.Optional;
+
 import org.springframework.util.Assert;
 
 /**
@@ -120,4 +122,13 @@ public interface Pageable {
 	 * @return
 	 */
 	boolean hasPrevious();
+
+	/**
+	 * Returns an {@link Optional} so that it can easily be mapped on.
+	 * 
+	 * @return
+	 */
+	default Optional<Pageable> toOptional() {
+		return isUnpaged() ? Optional.empty() : Optional.of(this);
+	}
 }

src/main/java/org/springframework/data/querydsl/QuerydslPredicateExecutor.java

@@ -83,7 +83,7 @@ public interface QuerydslPredicateExecutor<T> {
 	 * {@link Page} is returned.
 	 * 
 	 * @param predicate can be {@literal null}.
-	 * @param pageable can be {@literal null}.
+	 * @param pageable must not be {@literal null}.
 	 * @return a {@link Page} of entities matching the given {@link Predicate}.
 	 */
 	Page<T> findAll(Predicate predicate, Pageable pageable);

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

@@ -54,7 +54,7 @@ public class PageableHandlerMethodArgumentResolver implements PageableArgumentRe
 	private static final int DEFAULT_MAX_PAGE_SIZE = 2000;
 	static final Pageable DEFAULT_PAGE_REQUEST = PageRequest.of(0, 20);
 
-	private Optional<Pageable> fallbackPageable = Optional.of(DEFAULT_PAGE_REQUEST);
+	private Pageable fallbackPageable = DEFAULT_PAGE_REQUEST;
 	private SortArgumentResolver sortResolver;
 	private String pageParameterName = DEFAULT_PAGE_PARAMETER;
 	private String sizeParameterName = DEFAULT_SIZE_PARAMETER;
@@ -101,7 +101,7 @@ public class PageableHandlerMethodArgumentResolver implements PageableArgumentRe
 	 * 
 	 * @param fallbackPageable the {@link Pageable} to be used as general fallback.
 	 */
-	public void setFallbackPageable(Optional<Pageable> fallbackPageable) {
+	public void setFallbackPageable(Pageable fallbackPageable) {
 
 		Assert.notNull(fallbackPageable, "Fallback Pageable must not be null!");
 
@@ -240,7 +240,7 @@ public class PageableHandlerMethodArgumentResolver implements PageableArgumentRe
 
 		assertPageableUniqueness(methodParameter);
 
-		Optional<Pageable> defaultOrFallback = getDefaultFromAnnotationOrFallback(methodParameter);
+		Optional<Pageable> defaultOrFallback = getDefaultFromAnnotationOrFallback(methodParameter).toOptional();
 
 		String pageString = webRequest.getParameter(getParameterNameToUse(pageParameterName, methodParameter));
 		String pageSizeString = webRequest.getParameter(getParameterNameToUse(sizeParameterName, methodParameter));
@@ -252,8 +252,8 @@ public class PageableHandlerMethodArgumentResolver implements PageableArgumentRe
 			return null;
 		}
 
-		int p = page.orElseGet(
-				() -> defaultOrFallback.map(Pageable::getPageNumber).orElseThrow(IllegalStateException::new));
+		int p = page
+				.orElseGet(() -> defaultOrFallback.map(Pageable::getPageNumber).orElseThrow(IllegalStateException::new));
 		int ps = pageSize
 				.orElseGet(() -> defaultOrFallback.map(Pageable::getPageSize).orElseThrow(IllegalStateException::new));
 
@@ -288,10 +288,10 @@ public class PageableHandlerMethodArgumentResolver implements PageableArgumentRe
 		return builder.append(source).toString();
 	}
 
-	private Optional<Pageable> getDefaultFromAnnotationOrFallback(MethodParameter methodParameter) {
+	private Pageable getDefaultFromAnnotationOrFallback(MethodParameter methodParameter) {
 
 		if (methodParameter.hasParameterAnnotation(PageableDefault.class)) {
-			return Optional.of(getDefaultPageRequestFrom(methodParameter));
+			return getDefaultPageRequestFrom(methodParameter);
 		}
 
 		return fallbackPageable;