com.vaadin.flow.data.provider

Class Query<T,F>

java.lang.Object

com.vaadin.flow.data.provider.Query<T,F>

Type Parameters:

T - bean type

F - filter type

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

HierarchicalQuery

public class Query<T,F>
extends Object
implements Serializable

Immutable query object used to request data from a backend. Contains index limits, sorting and filtering information.

Since:

1.0

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
Query() Constructs a Query for all rows from 0 to Integer.MAX_VALUE without sorting and filtering.
Query(F filter) Constructs a Query for all rows from 0 to Integer.MAX_VALUE with filtering.
Query(int offset, int limit, List<QuerySortOrder> sortOrders, Comparator<T> inMemorySorting, F filter) Constructs a new Query object with given offset, limit, sorting and filtering.

Method Summary

Modifier and Type	Method and Description
Optional<F>	getFilter() Gets the filter for items to fetch.
Comparator<T>	getInMemorySorting() Gets the comparator for sorting in-memory data.
int	getLimit() Gets the number of items to fetch.
int	getOffset() Gets the first index of items to fetch.
int	getPage() Returns a zero-based page index to be retrieved.
int	getPageSize() Returns the page size that should be returned.
int	getRequestedRangeEnd() Gets the requested range end.
Optional<Comparator<T>>	getSortingComparator() Gets the optional comparator for sorting data.
List<QuerySortOrder>	getSortOrders() Gets the sorting for items to fetch.

Methods inherited from class java.lang.Object

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

Constructor Detail

Query

public Query()

Constructs a Query for all rows from 0 to Integer.MAX_VALUE without sorting and filtering.

Query

public Query(F filter)

Constructs a Query for all rows from 0 to Integer.MAX_VALUE with filtering.

Parameters:

filter - back end filter of a suitable type for the data provider; can be null

Query

public Query(int offset,
             int limit,
             List<QuerySortOrder> sortOrders,
             Comparator<T> inMemorySorting,
             F filter)

Constructs a new Query object with given offset, limit, sorting and filtering.

Parameters:

offset - first index to fetch

limit - fetched item count

sortOrders - sorting order for fetching; used for sorting backends

inMemorySorting - comparator for sorting in-memory data

filter - filtering for fetching; can be null

Method Detail

getOffset

public int getOffset()

Gets the first index of items to fetch. The offset is only used when fetching items, but not when counting the number of available items.

Returns:

offset for data request

getLimit

public int getLimit()

Gets the number of items to fetch. The limit is only used when fetching items, but not when counting the number of available items.

Note: It is possible that offset + limit > item count

Returns:

number of items to fetch

getPage

public int getPage()

Returns a zero-based page index to be retrieved.

Vaadin asks data from the backend in paged manner. This shorthand calculates the page index for backends using paged data access, such as Spring Data repositories.

Returns:

the zero-based page index

getPageSize

public int getPageSize()

Returns the page size that should be returned. The amount of items can be smaller if there is no more items available in the backend.

Vaadin asks data from the backend in paged manner.

This is an alias for getLimit() if the page offset can be evenly divided by the limit. Else the page size will be increased to evenly divide offset so the items skip for page will go to the correct item.

Returns:

the page size used for data access

getSortOrders

public List<QuerySortOrder> getSortOrders()

Gets the sorting for items to fetch. This list of sort orders is used for sorting backends. The sort orders are only used when fetching items, but not when counting the number of available items.

Note: Sort orders and in-memory sorting are mutually exclusive. If the DataProvider handles one, it should ignore the other.

Returns:

list of sort orders

getFilter

public Optional<F> getFilter()

Gets the filter for items to fetch.

Returns:

optional filter

getInMemorySorting

public Comparator<T> getInMemorySorting()

Gets the comparator for sorting in-memory data. The comparator is only used when fetching items, but not when counting the number of available items.

Note: Sort orders and in-memory sorting are mutually exclusive. If the DataProvider handles one, it should ignore the other.

Returns:

sorting comparator

getSortingComparator

public Optional<Comparator<T>> getSortingComparator()

Gets the optional comparator for sorting data. The comparator is only used when fetching items, but not when counting the number of available items.

Note: Sort orders and comparator sorting are mutually exclusive. If the DataProvider handles one, it should ignore the other.

Returns:

optional sorting comparator

getRequestedRangeEnd

public int getRequestedRangeEnd()

Gets the requested range end. This is a shorthand for getOffset() + getLimit() where the end is exclusive.

Returns:

the requested range end