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com.vaadin.flow.internal.
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

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