Package org.springframework.data.gemfire.repository.query.support

Class PagingUtils

java.lang.Object

org.springframework.data.gemfire.repository.query.support.PagingUtils

public abstract class PagingUtils
extends Object

Utility class used to work with Collection, Page and Pageable objects.

Since:

2.4.0

Author:

John Blum

See Also:

• Collection
• Page
• Pageable
• QueryMethod

Field Summary

Fields

Modifier and Type	Field	Description
protected static final Function<QueryMethod,Boolean>	DEFAULT_IS_PAGE_QUERY_FUNCTION
static final String	INVALID_PAGE_NUMBER_MESSAGE
static final String	INVALID_PAGE_SIZE_MESSAGE
static final String	NON_NULL_PAGEABLE_MESSAGE

Constructor Summary

Constructors

Constructor	Description
PagingUtils()

Method Summary

Modifier and Type	Method	Description
static void	assertPageable(Pageable pageable)	Asserts that the Pageable object is valid.
static <T> List<T>	getPagedList(List<T> list, Pageable pageable)	Gets a page from the given List.
static Pageable	getPageRequest(QueryMethod queryMethod, Object... arguments)	Finds the page request argument from an array of arguments passed to the given QueryMethod.
static int	getQueryResultSetEndIndexForPage(Pageable pageable)	Null-safe method used to determine the end index in the query result set for populating the content of the Page.
static int	getQueryResultSetLimitForPage(Pageable pageable)	Null-safe method used to determine the maximum results that would be returned by a query given the Pageable object specifying the requested Page.
static int	getQueryResultSetStartIndexForPage(Pageable pageable)	Null-safe method used to determine the starting index in the query result set for populating the content of the Page.
static boolean	isPageOne(Pageable pageable)	Null-safe method to determine whether the given page request is for page one.
static boolean	isPagingPresent(QueryMethod queryMethod)	Null-safe method used to determine whether the given QueryMethod represents (models) a paged query.
protected static int	normalize(int pageNumber)	Normalizes 0 index based page numbers (i.e. 0, 1, 2, ...) to natural page numbers (i.e. 1, 2, 3, ...).
static int	normalizePageNumber(Page<?> page)	Null-safe method used to normalize 0 index based page numbers (i.e. 0, 1, 2, ...) to natural page numbers (i.e. 1, 2, 3, ...) using the given Page.
static int	normalizePageNumber(Pageable pageable)	Null-safe method used to normalize 0 index based page numbers (i.e. 0, 1, 2, ...) to natural page numbers (i.e. 1, 2, 3, ...) using the given Pageable.
protected static long	nullSafeSize(Iterable<?> iterable)	Null-safe method to determine the size (number of elements) of the Iterable.
static <T> Page<T>	toPage(List<T> list, Pageable pageable)	Gets a Page view from the given List based on the Pageable object (page request).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

INVALID_PAGE_NUMBER_MESSAGE

public static final String INVALID_PAGE_NUMBER_MESSAGE

See Also:

• Constant Field Values

INVALID_PAGE_SIZE_MESSAGE

public static final String INVALID_PAGE_SIZE_MESSAGE

See Also:

• Constant Field Values

NON_NULL_PAGEABLE_MESSAGE

public static final String NON_NULL_PAGEABLE_MESSAGE

See Also:

• Constant Field Values

DEFAULT_IS_PAGE_QUERY_FUNCTION

protected static final Function<QueryMethod,Boolean> DEFAULT_IS_PAGE_QUERY_FUNCTION

Constructor Details

PagingUtils

public PagingUtils()

Method Details

assertPageable

public static void assertPageable(@NonNull
 Pageable pageable)

Asserts that the Pageable object is valid.

Parameters:

pageable - Pageable object to evaluate.

Throws:

IllegalArgumentException - if Pageable is null or page number is less than 0 or the page size is less than 1.

See Also:

• Pageable

isPageOne

public static boolean isPageOne(@NonNull
 Pageable pageable)

Null-safe method to determine whether the given page request is for page one.

Parameters:

pageable - page request to evaluate.

Returns:

a boolean value indicating whether the given page request is for page one.

See Also:

• Pageable

isPagingPresent

public static boolean isPagingPresent(@Nullable
 QueryMethod queryMethod)

Null-safe method used to determine whether the given QueryMethod represents (models) a paged query.

Parameters:

queryMethod - QueryMethod to evaluate for paging.

Returns:

a boolean value indicating whether the given QueryMethod represents (models) a paged query.

See Also:

• QueryMethod

getPagedList

@NonNull
public static <T> List<T> getPagedList(@NonNull
 List<T> list,
 @NonNull
 Pageable pageable)

Gets a page from the given List. This method is null-safe, and guards against a null List and Pageable.

Type Parameters:

T - type of the List elements; must not be null.

Parameters:

list - List from which to extract a page of elements; must not be null.

pageable - Pageable object encapsulating the details for the page requested.

Returns:

a sub-List containing the contents for the requested page.

See Also:

• getQueryResultSetStartIndexForPage(Pageable)
• getQueryResultSetEndIndexForPage(Pageable)
• Pageable
• List

getPageRequest

@NonNull
public static Pageable getPageRequest(@NonNull
 QueryMethod queryMethod,
 @NonNull
 Object... arguments)

Finds the page request argument from an array of arguments passed to the given QueryMethod.

Parameters:

queryMethod - invoked QueryMethod; must not be null.

arguments - array of arguments passed to the QueryMethod; must not be null.

Returns:

the page request argument in the array of arguments passed to the QueryMethod.

Throws:

IllegalArgumentException - if QueryMethod is null, or the QueryMethod parameter count is not equal to the argument count, or the indexed QueryMethod argument is not an instance of Pageable.

IllegalStateException - if the QueryMethod does not have a Pageable parameter.

See Also:

• QueryMethod
• Pageable

getQueryResultSetStartIndexForPage

public static int getQueryResultSetStartIndexForPage(@Nullable
 Pageable pageable)

Null-safe method used to determine the starting index in the query result set for populating the content of the Page.

Parameters:

pageable - Pageable object encapsulating the details of the requested Page.

Returns:

the start index in the query result set to populate the content of the Page.

See Also:

• Pageable
• getQueryResultSetEndIndexForPage(Pageable)

getQueryResultSetEndIndexForPage

public static int getQueryResultSetEndIndexForPage(@Nullable
 Pageable pageable)

Null-safe method used to determine the end index in the query result set for populating the content of the Page.

Parameters:

pageable - Pageable object encapsulating the details of the requested Page.

Returns:

the end index in the query result set to populate the content of the Page.

See Also:

• Pageable
• getQueryResultSetStartIndexForPage(Pageable)

getQueryResultSetLimitForPage

public static int getQueryResultSetLimitForPage(@Nullable
 Pageable pageable)

Null-safe method used to determine the maximum results that would be returned by a query given the Pageable object specifying the requested Page.

Parameters:

pageable - Pageable object encapsulating the details of the requested Page.

Returns:

the maximum results that would be returned by a query given the Pageable object specifying the requested Page.

See Also:

• Pageable
• normalizePageNumber(Pageable)

normalizePageNumber

public static int normalizePageNumber(@Nullable
 Page<?> page)

Null-safe method used to normalize 0 index based page numbers (i.e. 0, 1, 2, ...) to natural page numbers (i.e. 1, 2, 3, ...) using the given Page.

Parameters:

page - Page used to determine the page number to normalize.

Returns:

the normalized page number from the 0 index based page number.

See Also:

• Page
• normalize(int)

normalizePageNumber

public static int normalizePageNumber(@Nullable
 Pageable pageable)

Null-safe method used to normalize 0 index based page numbers (i.e. 0, 1, 2, ...) to natural page numbers (i.e. 1, 2, 3, ...) using the given Pageable.

Parameters:

pageable - Pageable used to determine the page number to normalize.

Returns:

the normalized page number from the 0 index based page number.

See Also:

• Pageable
• normalize(int)

normalize

protected static int normalize(int pageNumber)

Normalizes 0 index based page numbers (i.e. 0, 1, 2, ...) to natural page numbers (i.e. 1, 2, 3, ...).

Parameters:

pageNumber - The page number to normalize.

Returns:

the normalized page number from the 0 index based page number.

nullSafeSize

protected static long nullSafeSize(@Nullable
 Iterable<?> iterable)

Null-safe method to determine the size (number of elements) of the Iterable. The Iterable object may be an array, a Collection or simply a stream backing, pure Iterable object.

Parameters:

iterable - Iterable object to evaluate.

Returns:

the size (number of elements) contained by the Iterable object. If the Iterable object is null, then this method will return 0.

See Also:

• Iterable

toPage

@NonNull
public static <T> Page<T> toPage(@NonNull
 List<T> list,
 @NonNull
 Pageable pageable)

Gets a Page view from the given List based on the Pageable object (page request).

Type Parameters:

T - type of the List elements.

Parameters:

list - List of content from which to extract a Page; must not be null.

pageable - Pageable object encapsulating the details of the Page requested; must not be null.

Returns:

a non-null Page view from the given List based on the Pageable object (page request).

See Also:

• Pageable
• Page
• getPagedList(List, Pageable)
• List