DATACMNS-286 - Extended Page/Pageable APIs.

Pageable and Page interfaces now expose API to easily access Pageables pointing to the previous and next Page instance if available.

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

@@ -90,6 +90,24 @@ public interface Page<T> extends Iterable<T> {
 	 */
 	boolean isLastPage();
 
+	/**
+	 * Returns the {@link Pageable} to request the next {@link Page}. Can be {@literal null} in case the current
+	 * {@link Page} is already the last one. Clients should check {@link #hasNextPage()} before calling this method to
+	 * make sure they receive a non-{@literal null} value.
+	 * 
+	 * @return
+	 */
+	Pageable nextPageable();
+
+	/**
+	 * Returns the {@link Pageable} to request the previous page. Can be {@literal null} in case the current {@link Page}
+	 * is already the first one. Clients should check {@link #hasPreviousPage()} before calling this method make sure
+	 * receive a non-{@literal null} value.
+	 * 
+	 * @return
+	 */
+	Pageable previousPageable();
+
 	/*
 	 * (non-Javadoc)
 	 * @see java.lang.Iterable#iterator()

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

@@ -135,6 +135,27 @@ public class PageImpl<T> implements Page<T>, Serializable {
 		return !hasNextPage();
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.domain.Page#nextPageable()
+	 */
+	public Pageable nextPageable() {
+		return hasNextPage() ? pageable.next() : null;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.domain.Page#previousOrFirstPageable()
+	 */
+	public Pageable previousPageable() {
+
+		if (hasPreviousPage()) {
+			return pageable.previousOrFirst();
+		}
+
+		return null;
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.domain.Page#iterator()

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2012 the original author or authors.
+ * Copyright 2008-2013 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.
@@ -40,7 +40,6 @@ public class PageRequest implements Pageable, Serializable {
 	 * @param page
 	 */
 	public PageRequest(int page, int size) {
-
 		this(page, size, null);
 	}
 
@@ -53,7 +52,6 @@ public class PageRequest implements Pageable, Serializable {
 	 * @param properties
 	 */
 	public PageRequest(int page, int size, Direction direction, String... properties) {
-
 		this(page, size, new Sort(direction, properties));
 	}
 
@@ -62,16 +60,16 @@ public class PageRequest implements Pageable, Serializable {
 	 * 
 	 * @param page
 	 * @param size
-	 * @param sort
+	 * @param sort can be {@literal null}.
 	 */
 	public PageRequest(int page, int size, Sort sort) {
 
-		if (0 > page) {
+		if (page < 0) {
 			throw new IllegalArgumentException("Page index must not be less than zero!");
 		}
 
-		if (0 >= size) {
-			throw new IllegalArgumentException("Page size must not be less than or equal to zero!");
+		if (size < 0) {
+			throw new IllegalArgumentException("Page size must not be less than zero!");
 		}
 
 		this.page = page;
@@ -80,50 +78,74 @@ public class PageRequest implements Pageable, Serializable {
 	}
 
 	/*
-			 * (non-Javadoc)
-			 *
-			 * @see org.springframework.data.domain.Pageable#getPageSize()
-			 */
+	 * (non-Javadoc)
+	 * @see org.springframework.data.domain.Pageable#getPageSize()
+	 */
 	public int getPageSize() {
 
 		return size;
 	}
 
 	/*
-			 * (non-Javadoc)
-			 *
-			 * @see org.springframework.data.domain.Pageable#getPageNumber()
-			 */
+	 * (non-Javadoc)
+	 * @see org.springframework.data.domain.Pageable#getPageNumber()
+	 */
 	public int getPageNumber() {
-
 		return page;
 	}
 
 	/*
-			 * (non-Javadoc)
-			 *
-			 * @see org.springframework.data.domain.Pageable#getFirstItem()
-			 */
+	 * (non-Javadoc)
+	 * @see org.springframework.data.domain.Pageable#getOffset()
+	 */
 	public int getOffset() {
-
 		return page * size;
 	}
 
 	/*
-			 * (non-Javadoc)
-			 *
-			 * @see org.springframework.data.domain.Pageable#getSort()
-			 */
+	 * (non-Javadoc)
+	 * @see org.springframework.data.domain.Pageable#getSort()
+	 */
 	public Sort getSort() {
-
 		return sort;
 	}
 
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.domain.Pageable#hasPrevious()
+	 */
+	public boolean hasPrevious() {
+		return page > 0;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.domain.Pageable#next()
+	 */
+	public Pageable next() {
+		return new PageRequest(page + 1, size, sort);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.domain.Pageable#previousOrFirst()
+	 */
+	public Pageable previousOrFirst() {
+		return hasPrevious() ? new PageRequest(page - 1, size, sort) : this;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.data.domain.Pageable#first()
+	 */
+	public Pageable first() {
+		return new PageRequest(0, size, sort);
+	}
+
 	/*
-			 * (non-Javadoc)
-			 *
-			 * @see java.lang.Object#equals(java.lang.Object)
-			 */
+	 * (non-Javadoc)
+	 * @see java.lang.Object#equals(java.lang.Object)
+	 */
 	@Override
 	public boolean equals(final Object obj) {
 
@@ -146,10 +168,9 @@ public class PageRequest implements Pageable, Serializable {
 	}
 
 	/*
-			 * (non-Javadoc)
-			 *
-			 * @see java.lang.Object#hashCode()
-			 */
+	 * (non-Javadoc)
+	 * @see java.lang.Object#hashCode()
+	 */
 	@Override
 	public int hashCode() {
 
@@ -161,4 +182,14 @@ public class PageRequest implements Pageable, Serializable {
 
 		return result;
 	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Object#toString()
+	 */
+	@Override
+	public String toString() {
+		return String.format("Page request [number: %d, size %d, sort: %s]", page, size,
+				sort == null ? null : sort.toString());
+	}
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2010 the original author or authors.
+ * Copyright 2008-2013 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.
@@ -49,4 +49,33 @@ public interface Pageable {
 	 * @return
 	 */
 	Sort getSort();
+
+	/**
+	 * Returns the {@link Pageable} requesting the next {@link Page}.
+	 * 
+	 * @return
+	 */
+	Pageable next();
+
+	/**
+	 * Returns the previous {@link Pageable} or the first {@link Pageable} if the current one already is the first one.
+	 * 
+	 * @return
+	 */
+	Pageable previousOrFirst();
+
+	/**
+	 * Returns the {@link Pageable} requesting the first page.
+	 * 
+	 * @return
+	 */
+	Pageable first();
+
+	/**
+	 * Returns whether there's a previous {@link Pageable} we can access from the current one. Will return
+	 * {@literal false} in case the current {@link Pageable} already refers to the first page.
+	 * 
+	 * @return
+	 */
+	boolean hasPrevious();
 }

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

@@ -199,6 +199,7 @@ public class Sort implements Iterable<org.springframework.data.domain.Sort.Order
 		 * Returns the {@link Direction} enum for the given {@link String} value.
 		 * 
 		 * @param value
+		 * @throws IllegalArgumentException in case the given value cannot be parsed into an enum value.
 		 * @return
 		 */
 		public static Direction fromString(String value) {
@@ -210,6 +211,22 @@ public class Sort implements Iterable<org.springframework.data.domain.Sort.Order
 						"Invalid value '%s' for orders given! Has to be either 'desc' or 'asc' (case insensitive).", value), e);
 			}
 		}
+
+		/**
+		 * Returns the {@link Direction} enum for the given {@link String} or null if it cannot be parsed into an enum
+		 * value.
+		 * 
+		 * @param value
+		 * @return
+		 */
+		public static Direction fromStringOrNull(String value) {
+
+			try {
+				return fromString(value);
+			} catch (IllegalArgumentException e) {
+				return null;
+			}
+		}
 	}
 
 	/**