Package com.oorian.data

Class CallbackDataProvider<T>

java.lang.Object

com.oorian.data.AbstractDataProvider<T>

com.oorian.data.CallbackDataProvider<T>

Type Parameters:

T - the data item type

All Implemented Interfaces:

DataProvider<T>

public class CallbackDataProvider<T>
extends AbstractDataProvider<T>

A data provider that delegates fetching and counting to user-provided callbacks.

Use this for database-backed lazy loading where the callbacks translate Query parameters into SQL queries, REST API calls, or other data access.

 DataProvider<User> provider = new CallbackDataProvider<>(
     query -> {
         List<User> users = userDao.findAll(
             query.getOffset(), query.getLimit(),
             query.getSorts(), query.getFilters());
         int total = userDao.count(query.getFilters());
         return DataResult.of(users, total);
     },
     query -> userDao.count(query.getFilters())
 );
 

Since:

2.1

Version:

1.0

Author:

Marvin P. Warble Jr.

See Also:

• DataProvider
• ListDataProvider

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	CallbackDataProvider.CountCallback	Callback for counting matching items.
static interface	CallbackDataProvider.FetchCallback<T>	Callback for fetching a page of data.

Constructor Summary

Constructors

Constructor	Description
CallbackDataProvider(CallbackDataProvider.FetchCallback<T> fetchCallback, CallbackDataProvider.CountCallback countCallback)	Creates a callback data provider.

Method Summary

Modifier and Type	Method	Description
DataResult<T>	fetch(Query query)	Fetches a page of data matching the query parameters.
int	size(Query query)	Returns the total number of items matching the query's filters.

Methods inherited from class com.oorian.data.AbstractDataProvider

addDataChangeListener, refresh, removeDataChangeListener

Methods inherited from class java.lang.Object

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

Constructor Details

CallbackDataProvider

public CallbackDataProvider(CallbackDataProvider.FetchCallback<T> fetchCallback,
 CallbackDataProvider.CountCallback countCallback)

Creates a callback data provider.

Parameters:

fetchCallback - the callback for fetching data pages

countCallback - the callback for counting matching items

Method Details

fetch

public DataResult<T> fetch(Query query)

Description copied from interface: DataProvider

Fetches a page of data matching the query parameters.

Parameters:

query - the query with offset, limit, sorts, and filters

Returns:

the result containing items and total count

size

public int size(Query query)

Description copied from interface: DataProvider

Returns the total number of items matching the query's filters.

Parameters:

query - the query (only filters are relevant; offset/limit are ignored)

Returns:

the total count of matching items