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.

Since:

1.0

Author:

Vaadin Ltd

See Also:

Serialized Form

Method Summary

Modifier and Type	Method and Description
static NullOwner	get() Gets the singleton null owner instance.
boolean	hasNode(StateNode node) Check if given node is registered to this node owner.
void	markAsDirty(StateNode node) Marks a node owned by this instance as dirty.
int	register(StateNode node) Registers a node with this node owner.
void	unregister(StateNode node) Unregisters a node from this owner.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

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