We use cookies to serve our customers and website visitors in the best possible way. Cookies are used for the proper functioning of the website and for improving the user experience, monitoring visitor traffic and marketing purposes. By continuing to browse the site, you agree to our use of cookies. You can read more about cookies here.
com.vaadin.flow.data.provider.
Class CallbackDataProvider<T,F>
- java.lang.Object
-
- com.vaadin.flow.data.provider.AbstractDataProvider<T,F>
-
- com.vaadin.flow.data.provider.AbstractBackEndDataProvider<T,F>
-
- com.vaadin.flow.data.provider.CallbackDataProvider<T,F>
-
Type Parameters:
T- data provider data typeF- data provider filter typeAll Implemented Interfaces:
BackEndDataProvider<T,F>,DataProvider<T,F>,Serializablepublic class CallbackDataProvider<T,F> extends AbstractBackEndDataProvider<T,F>Data provider that uses one callback for fetching items from a back end and another callback for counting the number of available items.
Since:
1.0
Author:
Vaadin Ltd
See Also:
-
-
Nested Class Summary
Nested Classes Modifier and Type Class Description static interfaceCallbackDataProvider.CountCallback<T,F>Callback interface for counting the number of items in a backend based on a query.
static interfaceCallbackDataProvider.FetchCallback<T,F>Callback interface for fetching a stream of items from a backend based on a query.
-
Constructor Summary
Constructors Constructor Description CallbackDataProvider(CallbackDataProvider.FetchCallback<T,F> fetchCallback, CallbackDataProvider.CountCallback<T,F> countCallback)Constructs a new DataProvider to request data using callbacks for fetching and counting items in the back end.
CallbackDataProvider(CallbackDataProvider.FetchCallback<T,F> fetchCallBack, CallbackDataProvider.CountCallback<T,F> countCallback, ValueProvider<T,Object> identifierGetter)Constructs a new DataProvider to request data using callbacks for fetching and counting items in the back end.
-
Method Summary
All Methods Modifier and Type Method Description Stream<T>fetchFromBackEnd(Query<T,F> query)Fetches data from the back end using the given query.
ObjectgetId(T item)Gets an identifier for the given item.
protected intsizeInBackEnd(Query<T,F> query)Counts the number of items available in the back end.
-
Methods inherited from class com.vaadin.flow.data.provider.AbstractBackEndDataProvider
fetch, setSortOrders, size
-
Methods inherited from class com.vaadin.flow.data.provider.AbstractDataProvider
addDataProviderListener, addListener, fireEvent, refreshAll, refreshItem, refreshItem
-
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
-
Methods inherited from interface com.vaadin.flow.data.provider.BackEndDataProvider
isInMemory, setSortOrder, setSortOrders
-
Methods inherited from interface com.vaadin.flow.data.provider.DataProvider
addDataProviderListener, refreshAll, refreshItem, refreshItem, withConfigurableFilter, withConfigurableFilter, withConvertedFilter
-
-
-
-
Constructor Detail
-
CallbackDataProvider
public CallbackDataProvider(CallbackDataProvider.FetchCallback<T,F> fetchCallback, CallbackDataProvider.CountCallback<T,F> countCallback)Constructs a new DataProvider to request data using callbacks for fetching and counting items in the back end.
Parameters:
fetchCallback- function that returns a stream of items from the back end for a querycountCallback- function that return the number of items in the back end for a querySee Also:
CallbackDataProvider(FetchCallback, CountCallback, ValueProvider)
-
CallbackDataProvider
public CallbackDataProvider(CallbackDataProvider.FetchCallback<T,F> fetchCallBack, CallbackDataProvider.CountCallback<T,F> countCallback, ValueProvider<T,Object> identifierGetter)Constructs a new DataProvider to request data using callbacks for fetching and counting items in the back end.
Parameters:
fetchCallBack- function that requests data from back end based on querycountCallback- function that returns the amount of data in back end for queryidentifierGetter- function that returns the identifier for a given item
-
-
Method Detail
-
fetchFromBackEnd
public Stream<T> fetchFromBackEnd(Query<T,F> query)Description copied from class:
AbstractBackEndDataProviderFetches data from the back end using the given query.
Specified by:
fetchFromBackEndin classAbstractBackEndDataProvider<T,F>Parameters:
query- the query that defines sorting, filtering and paging for fetching the dataReturns:
a stream of items matching the query
-
sizeInBackEnd
protected int sizeInBackEnd(Query<T,F> query)Description copied from class:
AbstractBackEndDataProviderCounts the number of items available in the back end.
Specified by:
sizeInBackEndin classAbstractBackEndDataProvider<T,F>Parameters:
query- the query that defines filtering to be used for counting the number of itemsReturns:
the number of available items
-
getId
public Object getId(T item)Description copied from interface:
DataProviderGets an identifier for the given item. This identifier is used by the framework to determine equality between two items.
Default is to use item itself as its own identifier. If the item has
Object.equals(Object)andObject.hashCode()implemented in a way that it can be compared to other items, no changes are required.Note: This method will be called often by the Framework. It should not do any expensive operations.
Parameters:
item- the item to get identifier for; notnullReturns:
the identifier for given item; not
null
-
-