com.vaadin.flow.internal

Class StateTree

java.lang.Object

com.vaadin.flow.internal.StateTree

All Implemented Interfaces:

NodeOwner, Serializable

public class StateTree
extends Object
implements NodeOwner

The state tree that is synchronized with the client-side.

Since:

1.0

Author:

Vaadin Ltd

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	StateTree.BeforeClientResponseEntry A task to be executed before the client response, together with an execution sequence number and context object.
static interface	StateTree.ExecutionRegistration A registration object for removing a task registered for execution before the client response.

Constructor Summary

Constructors

Constructor and Description
StateTree(UIInternals uiInternals, Class<? extends NodeFeature>... features) Creates a new state tree with a set of features defined for the root node.

Method Summary

Modifier and Type	Method and Description
StateTree.ExecutionRegistration	beforeClientResponse(StateNode context, SerializableConsumer<ExecutionContext> execution) Registers a task to be executed before the response is sent to the client.
void	collectChanges(Consumer<NodeChange> collector) Collects all changes made to this tree since the last time collectChanges(Consumer) has been called.
Set<StateNode>	collectDirtyNodes() Gets all the nodes that have been marked.
StateNode	getNodeById(int id) Finds a node with the given id.
StateNode	getRootNode() Gets the root node of this state tree.
UI	getUI() Gets the UI that this tree belongs to.
boolean	hasDirtyNodes() Checks if there are nodes that have been marked as dirty since the last time collectDirtyNodes() was invoked.
boolean	hasNode(StateNode node) Check if given node is registered to this node owner.
boolean	isDirty() Checks if there are changes waiting to be sent to the client side.
void	markAsDirty(StateNode node) Marks a node owned by this instance as dirty.
void	prepareForResync() Prepares the tree for resynchronization, meaning that the client will receive the same changes as when the component tree was initially attached, so that it can build the DOM tree from scratch.
int	register(StateNode node) Registers a node with this node owner.
void	runExecutionsBeforeClientResponse() Called internally by the framework before the response is sent to the client.
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

Constructor Detail

StateTree

@SafeVarargs
public StateTree(UIInternals uiInternals,
                              Class<? extends NodeFeature>... features)

Creates a new state tree with a set of features defined for the root node.

Parameters:

features - the features of the root node

uiInternals - the internals for the UI that this tree belongs to

Method Detail

getRootNode

public StateNode getRootNode()

Gets the root node of this state tree. The root node is created together with the tree and can't be detached.

Returns:

the root node

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

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

getNodeById

public StateNode getNodeById(int id)

Finds a node with the given id.

Parameters:

id - the node id to look for

Returns:

the node with the given id; null if the id is not registered with this tree

See Also:

StateNode.getId()

collectChanges

public void collectChanges(Consumer<NodeChange> collector)

Collects all changes made to this tree since the last time collectChanges(Consumer) has been called.

WARNING: This is an internal method which is not intended to be used outside. The only proper caller of this method is UidlWriter class (the UidlWriter::encodeChanges method). Any call of this method in any other place will break the expected UI state.

Parameters:

collector - a consumer accepting node changes

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 collectDirtyNodes().

Specified by:

markAsDirty in interface NodeOwner

Parameters:

node - the node to be marked as dirty

collectDirtyNodes

public Set<StateNode> collectDirtyNodes()

Gets all the nodes that have been marked.

Returns:

a set of dirty nodes, in the order they were marked dirty

hasDirtyNodes

public boolean hasDirtyNodes()

Checks if there are nodes that have been marked as dirty since the last time collectDirtyNodes() was invoked.

Returns:

true if there are dirty nodes, false otherwise

getUI

public UI getUI()

Gets the UI that this tree belongs to.

Returns:

the UI that this tree belongs to

beforeClientResponse

public StateTree.ExecutionRegistration beforeClientResponse(StateNode context,
                                                            SerializableConsumer<ExecutionContext> execution)

Registers a task to be executed before the response is sent to the client. The tasks are executed in order of registration. If tasks register more tasks, they are executed after all already registered tasks for the moment.

Example: three tasks are submitted, A, B and C, where B produces two more tasks during execution, D and E. The resulting execution would be ABCDE.

If the StateNode related to the task is not attached to the document by the time the task is evaluated, the execution is postponed to before the next response.

The task receives a ExecutionContext as parameter, which contains information about the node state before the response.

Parameters:

context - the StateNode relevant for the execution. Can not be null

execution - the task to be executed. Can not be null

Returns:

a registration that can be used to cancel the execution of the task

runExecutionsBeforeClientResponse

public void runExecutionsBeforeClientResponse()

Called internally by the framework before the response is sent to the client. All tasks registered at beforeClientResponse(StateNode, SerializableConsumer) are evaluated and executed if able.

isDirty

public boolean isDirty()

Checks if there are changes waiting to be sent to the client side.

Returns:

true if there are pending changes, false otherwise

prepareForResync

public void prepareForResync()

Prepares the tree for resynchronization, meaning that the client will receive the same changes as when the component tree was initially attached, so that it can build the DOM tree from scratch.