Package com.vaadin.flow.internal.nodefeature

Class NodeFeature

java.lang.Object

com.vaadin.flow.internal.nodefeature.NodeFeature

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

NodeList, NodeMap, NodeValue, ServerSideFeature

public abstract class NodeFeature
extends Object
implements Serializable

A node feature represents a group of related values and functionality in a state node.

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

Since:

1.0

Author:

Vaadin Ltd

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
NodeFeature(StateNode node)	Creates a new feature for the given node.

Method Summary

Modifier and Type	Method	Description
boolean	allowsChanges()	Returns true if the underlying node may report its changes.
protected void	attachPotentialChild(Object child)	Attaches an object if it is a StateNode.
abstract void	collectChanges(Consumer<NodeChange> collector)	Collects all changes that are recorded for this feature.
protected void	detatchPotentialChild(Object child)	Detaches an object if it is a StateNode.
abstract void	forEachChild(Consumer<StateNode> action)	Passes each child node instance to the given consumer.
abstract void	generateChangesFromEmpty()	Generates all changes that would be needed to take this node from its initial empty state to its current state.
StateNode	getNode()	Gets the node that this feature belongs to.
void	onAttach(boolean initialAttach)	Called when the state node has been attached to the state tree.
void	onDetach()	Called when the state node has been detached from the state tree.

Methods inherited from class java.lang.Object

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

Constructor Detail

NodeFeature

public NodeFeature(StateNode node)

Creates a new feature for the given node.

Parameters:

node - the node which supports the feature

Method Detail

getNode

public StateNode getNode()

Gets the node that this feature belongs to.

Returns:

the node

collectChanges

public abstract void collectChanges(Consumer<NodeChange> collector)

Collects all changes that are recorded for this feature.

Parameters:

collector - a consumer accepting node changes

generateChangesFromEmpty

public abstract void generateChangesFromEmpty()

Generates all changes that would be needed to take this node from its initial empty state to its current state.

attachPotentialChild

protected void attachPotentialChild(Object child)

Attaches an object if it is a StateNode.

Parameters:

child - the instance to maybe attach

detatchPotentialChild

protected void detatchPotentialChild(Object child)

Detaches an object if it is a StateNode.

Parameters:

child - the instance to maybe detach

forEachChild

public abstract void forEachChild(Consumer<StateNode> action)

Passes each child node instance to the given consumer.

Parameters:

action - the consumer that accepts each child

onAttach

public void onAttach(boolean initialAttach)

Called when the state node has been attached to the state tree.

Parameters:

initialAttach - true if this is the first time the node is attached to a StateTree, false otherwise

onDetach

public void onDetach()

Called when the state node has been detached from the state tree.

allowsChanges

public boolean allowsChanges()

Returns true if the underlying node may report its changes.

If its return value is false then this node should be considered as "inactive" and should not send any changes to the client side at all or only changes for features that disallow the changes.

Normally features don't control the node behavior so the default implementation returns true. The feature which wants to control the node behavior should override this method.

Returns:

true if the feature allows changes for the node, false otherwise

See Also:

StateNode.updateActiveState()