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

Class 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 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.