Package com.vaadin.flow.internal

Class NullOwner

java.lang.Object
com.vaadin.flow.internal.NullOwner
All Implemented Interfaces:
NodeOwner, Serializable
public class NullOwner extends Object implements NodeOwner
A stateless singleton node owner that is used for nodes that have not yet been attached to a state tree. An instance of this type is used instead of a null pointer to avoid cluttering implementations with null checks.

For internal use only. May be renamed or removed in a future release.

Since:
1.0
Author:
Vaadin Ltd
See Also:

  • Method Details

    • get

      public static NullOwner get()
      Gets the singleton null owner instance.
      Returns:
      the singleton instance

    • register

      public int register(StateNode node)
      Description copied from interface: NodeOwner
      Registers a node with this node owner. The new node should already be set to be owned by this instance.
      Specified by:
      register in interface NodeOwner
      Parameters:
      node - the node to register
      Returns:
      the id of the registered node

    • unregister

      public void unregister(StateNode node)
      Description copied from interface: NodeOwner
      Unregisters a node from this owner. This must be done before the node is set to not be owned by this instance.
      Specified by:
      unregister in interface NodeOwner
      Parameters:
      node - the node to unregister

    • markAsDirty

      public void markAsDirty(StateNode node)
      Description copied from interface: NodeOwner
      Marks a node owned by this instance as dirty. Dirty nodes are collected from an owner using StateTree.collectDirtyNodes().
      Specified by:
      markAsDirty in interface NodeOwner
      Parameters:
      node - the node to be marked as dirty

    • hasNode

      public boolean hasNode(StateNode node)
      Description copied from interface: NodeOwner
      Check if given node is registered to this node owner.
      Specified by:
      hasNode in interface NodeOwner
      Parameters:
      node - node to check registration status for
      Returns:
      true if node is registered