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com.vaadin.data.provider.
Interface HierarchicalDataProvider<T,F>
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Type Parameters:
T- data typeF- filter typeAll Superinterfaces:
DataProvider<T,F>,SerializableAll Known Subinterfaces:
All Known Implementing Classes:
AbstractBackEndHierarchicalDataProvider,AbstractHierarchicalDataProvider,TreeDataProviderpublic interface HierarchicalDataProvider<T,F> extends DataProvider<T,F>A common interface for fetching hierarchical data from a data source, such as an in-memory collection or a backend database.
Since:
8.1
Author:
Vaadin Ltd
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Method Summary
All Methods Modifier and Type Method Description default Stream<T>fetch(Query<T,F> query)Fetches data from this HierarchicalDataProvider using given
query.Stream<T>fetchChildren(HierarchicalQuery<T,F> query)Fetches data from this HierarchicalDataProvider using given
query.intgetChildCount(HierarchicalQuery<T,F> query)Get the number of immediate child data items for the parent item returned by a given query.
booleanhasChildren(T item)Check whether a given item has any children associated with it.
default intsize(Query<T,F> query)Get the number of immediate child data items for the parent item returned by a given query.
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Methods inherited from interface com.vaadin.data.provider.DataProvider
addDataProviderListener, getId, isInMemory, refreshAll, refreshItem, withConfigurableFilter, withConfigurableFilter, withConvertedFilter
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Method Detail
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size
default int size(Query<T,F> query)Get the number of immediate child data items for the parent item returned by a given query.
Specified by:
sizein interfaceDataProvider<T,F>Parameters:
query- given query to request the count forReturns:
the count of child data items for the data item
HierarchicalQuery.getParent()Throws:
IllegalArgumentException- if the query is not of type HierarchicalQuery
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fetch
default Stream<T> fetch(Query<T,F> query)Fetches data from this HierarchicalDataProvider using given
query. Only the immediate children ofHierarchicalQuery.getParent()will be returned.NOTE: If your data request is likely to involve I/O channels, see
DataProvider.fetch(Query)for instructions on how to handle the stream without risking resource leaks.Specified by:
fetchin interfaceDataProvider<T,F>Parameters:
query- given query to request data withReturns:
a stream of data objects resulting from the query
Throws:
IllegalArgumentException- if the query is not of type HierarchicalQuery
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getChildCount
int getChildCount(HierarchicalQuery<T,F> query)Get the number of immediate child data items for the parent item returned by a given query.
Parameters:
query- given query to request the count forReturns:
the count of child data items for the data item
HierarchicalQuery.getParent()
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fetchChildren
Stream<T> fetchChildren(HierarchicalQuery<T,F> query)Fetches data from this HierarchicalDataProvider using given
query. Only the immediate children ofHierarchicalQuery.getParent()will be returned.NOTE: If your data request is likely to involve I/O channels, see
DataProvider.fetch(Query)for instructions on how to handle the stream without risking resource leaks.Parameters:
query- given query to request data withReturns:
a stream of data objects resulting from the query
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hasChildren
boolean hasChildren(T item)Check whether a given item has any children associated with it.
Parameters:
item- the item to check for childrenReturns:
whether the given item has children
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