com.vaadin.flow.data.provider.hierarchy.

java.lang.Object
- com.vaadin.flow.data.provider.hierarchy.HierarchyMapper<T,F>

Type Parameters:

T - the data type

F - the filter type

All Implemented Interfaces:

Serializable
```
public class HierarchyMapper<T,F>
extends Object
implements Serializable
```
Mapper for hierarchical data.
Keeps track of the expanded nodes, and size of of the subtrees for each expanded node.
This class is framework internal implementation details, and can be changed / moved at any point. This means that you should not directly use this for anything.

Since:

1.2

Author:

Vaadin Ltd

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor Description

HierarchyMapper(HierarchicalDataProvider<T,F> provider)
Constructs a new HierarchyMapper.

Method Summary

All Methods
Modifier and Type	Method	Description
`boolean`	`collapse(T item)`	Collapses the given item.
`Range`	`collapse(T item, Integer position)`	Collapses the given item.
`int`	`countChildItems(T parent)`
`void`	`destroyAllData()`
`boolean`	`expand(T item)`	Expands the given item.
`Range`	`expand(T item, Integer position)`	Expands the given item.
`Stream<T>`	`fetchChildItems(T parent, Range range)`
`Stream<T>`	`fetchHierarchyItems(Range range)`	Gets a stream of items in the form of a flattened hierarchy from the back-end and filter the wanted results from the list.
`Stream<T>`	`fetchHierarchyItems(T parent, Range range)`	Gets a stream of children for the given item in the form of a flattened hierarchy from the back-end and filter the wanted results from the list.
`Stream<T>`	`fetchRootItems(Range range)`	Gets a stream of root items from the back-end and filter the wanted results from the list.
`List<QuerySortOrder>`	`getBackEndSorting()`	Gets the current back-end sorting.
`HierarchicalDataProvider<T,F>`	`getDataProvider()`	Gets the `HierarchicalDataProvider` for this `HierarchyMapper`.
`int`	`getDepth(T item)`	Returns depth of item in the tree starting from zero representing a root.
`Collection<T>`	`getExpandedItems()`	Returns the expanded items in form of an unmodifiable collection.
`F`	`getFilter()`	Gets the current filter.
`Integer`	`getIndex(T item)`	Finds the index of the item in active tree.
`Optional<Integer>`	`getIndexOf(T target)`	Finds the current index of given object.
`Comparator<T>`	`getInMemorySorting()`	Gets the current in-memory sorting.
`Integer`	`getParentIndex(T item)`	Finds the index of the parent of the item in given target index.
`protected T`	`getParentOfItem(T item)`	Find parent for the given item among open folders.
`int`	`getRootSize()`	Returns the size of root level.
`int`	`getTreeSize()`	Returns the size of the currently expanded hierarchy.
`boolean`	`hasChildren(T item)`	Returns whether given item has children.
`boolean`	`hasExpandedItems()`	Returns true if there is any expanded items.
`boolean`	`isExpanded(T item)`	Returns whether the given item is expanded.
`protected void`	`registerChildren(T parent, List<T> childList)`	Register parent and children items into inner structures.
`protected void`	`removeChildren(Object id)`	Removes all children of an item identified by a given id.
`void`	`setBackEndSorting(List<QuerySortOrder> backEndSorting)`	Sets the current back-end sorting.
`void`	`setFilter(Object filter)`	Sets the current filter.
`void`	`setInMemorySorting(Comparator<T> inMemorySorting)`	Sets the current in-memory sorting.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - HierarchyMapper
```
public HierarchyMapper(HierarchicalDataProvider<T,F> provider)
```
    Constructs a new HierarchyMapper.
    
    Parameters:
    
    provider - the hierarchical data provider for this mapper
- Method Detail
  - getTreeSize
```
public int getTreeSize()
```
    Returns the size of the currently expanded hierarchy.
    
    Returns:
    
    the amount of available data
  - getRootSize
```
public int getRootSize()
```
    Returns the size of root level.
    
    Returns:
    
    the amount of available root data
  - getParentIndex
```
public Integer getParentIndex(T item)
```
    Finds the index of the parent of the item in given target index.
    
    Parameters:
    
    item - the item to get the parent of
    
    Returns:
    
    the parent index or a negative value if the parent is not found
  - getIndex
```
public Integer getIndex(T item)
```
    Finds the index of the item in active tree.
    
    Parameters:
    
    item - the target item
    
    Returns:
    
    the index or a negative value if item is not found
  - isExpanded
```
public boolean isExpanded(T item)
```
    Returns whether the given item is expanded.
    
    Parameters:
    
    item - the item to test
    
    Returns:
    
    true if item is expanded; false if not
  - expand
```
public boolean expand(T item)
```
    Expands the given item.
    
    Parameters:
    
    item - the item to expand
    
    Returns:
    
    true if this method expanded the item, false otherwise
  - expand
```
public Range expand(T item,
                    Integer position)
```
    Expands the given item.
    
    Parameters:
    
    item - the item to expand
    
    position - the index of the item
    
    Returns:
    
    range of rows added by expanding the item
  - collapse
```
public boolean collapse(T item)
```
    Collapses the given item.
    
    Parameters:
    
    item - the item to collapse
    
    Returns:
    
    true if item has been collapsed, false if item is empty or already collapsed
  - collapse
```
public Range collapse(T item,
                      Integer position)
```
    Collapses the given item.
    
    Parameters:
    
    item - the item to collapse
    
    position - the index of the item
    
    Returns:
    
    range of rows removed by collapsing the item
  - getInMemorySorting
```
public Comparator<T> getInMemorySorting()
```
    Gets the current in-memory sorting.
    
    Returns:
    
    the in-memory sorting
  - setInMemorySorting
```
public void setInMemorySorting(Comparator<T> inMemorySorting)
```
    Sets the current in-memory sorting. This will cause the hierarchy to be constructed again.
    
    Parameters:
    
    inMemorySorting - the in-memory sorting
  - getBackEndSorting
```
public List<QuerySortOrder> getBackEndSorting()
```
    Gets the current back-end sorting.
    
    Returns:
    
    the back-end sorting
  - setBackEndSorting
```
public void setBackEndSorting(List<QuerySortOrder> backEndSorting)
```
    Sets the current back-end sorting. This will cause the hierarchy to be constructed again.
    
    Parameters:
    
    backEndSorting - the back-end sorting
  - getFilter
```
public F getFilter()
```
    Gets the current filter.
    
    Returns:
    
    the filter
  - setFilter
```
public void setFilter(Object filter)
```
    Sets the current filter. This will cause the hierarchy to be constructed again.
    
    Parameters:
    
    filter - the filter
  - getDataProvider
```
public HierarchicalDataProvider<T,F> getDataProvider()
```
    Gets the HierarchicalDataProvider for this HierarchyMapper.
    
    Returns:
    
    the hierarchical data provider
  - hasChildren
```
public boolean hasChildren(T item)
```
    Returns whether given item has children.
    
    Parameters:
    
    item - the node to test
    
    Returns:
    
    true if node has children; false if not
  - fetchHierarchyItems
```
public Stream<T> fetchHierarchyItems(Range range)
```
    Gets a stream of items in the form of a flattened hierarchy from the back-end and filter the wanted results from the list.
    
    Parameters:
    
    range - the requested item range
    
    Returns:
    
    the stream of items
  - fetchHierarchyItems
```
public Stream<T> fetchHierarchyItems(T parent,
                                     Range range)
```
    Gets a stream of children for the given item in the form of a flattened hierarchy from the back-end and filter the wanted results from the list.
    
    Parameters:
    
    parent - the parent item for the fetch
    
    range - the requested item range
    
    Returns:
    
    the stream of items
  - fetchRootItems
```
public Stream<T> fetchRootItems(Range range)
```
    Gets a stream of root items from the back-end and filter the wanted results from the list.
    
    Parameters:
    
    range - the requested item range
    
    Returns:
    
    the stream of items
  - fetchChildItems
```
public Stream<T> fetchChildItems(T parent,
                                 Range range)
```
  - countChildItems
```
public int countChildItems(T parent)
```
  - getDepth
```
public int getDepth(T item)
```
    Returns depth of item in the tree starting from zero representing a root.
    
    Parameters:
    
    item - Target item
    
    Returns:
    
    depth of item in the tree or -1 if item is null
  - getParentOfItem
```
protected T getParentOfItem(T item)
```
    Find parent for the given item among open folders.
    
    Parameters:
    
    item - the item
    
    Returns:
    
    parent item or null for root items or if the parent is closed
  - removeChildren
```
protected void removeChildren(Object id)
```
    Removes all children of an item identified by a given id. Items removed by this method as well as the original item are all marked to be collapsed. May be overridden in subclasses for removing obsolete data to avoid memory leaks.
    
    Parameters:
    
    id - the item id
  - getIndexOf
```
public Optional<Integer> getIndexOf(T target)
```
    Finds the current index of given object. This is based on a search in flattened version of the hierarchy.
    
    Parameters:
    
    target - the target object to find
    
    Returns:
    
    optional index of given object
  - registerChildren
```
protected void registerChildren(T parent,
                                List<T> childList)
```
    Register parent and children items into inner structures. May be overridden in subclasses.
    
    Parameters:
    
    parent - the parent item
    
    childList - list of parents children to be registered.
  - destroyAllData
```
public void destroyAllData()
```
  - hasExpandedItems
```
public boolean hasExpandedItems()
```
    Returns true if there is any expanded items.
    
    Returns:
    
    true if there is any expanded items.
  - getExpandedItems
```
public Collection<T> getExpandedItems()
```
    Returns the expanded items in form of an unmodifiable collection.
    
    Returns:
    
    an unmodifiable Collection<T> containing the expanded items.

com.vaadin.flow.data.provider.hierarchy.

Class HierarchyMapper<T,​F>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

HierarchyMapper

Method Detail

getTreeSize

getRootSize

getParentIndex

getIndex

isExpanded

expand

expand

collapse

collapse

getInMemorySorting

setInMemorySorting

getBackEndSorting

setBackEndSorting

getFilter

setFilter

getDataProvider

hasChildren

fetchHierarchyItems

fetchHierarchyItems

fetchRootItems

fetchChildItems

countChildItems

getDepth

getParentOfItem

removeChildren

getIndexOf

registerChildren

destroyAllData

hasExpandedItems

getExpandedItems

Class HierarchyMapper<T,F>