org.codefx.libfx.collection.tree.navigate

Class SceneGraphNavigator

java.lang.Object

org.codefx.libfx.collection.tree.navigate.SceneGraphNavigator

All Implemented Interfaces:

TreeNavigator<javafx.scene.Node>

public class SceneGraphNavigator
extends Object
implements TreeNavigator<javafx.scene.Node>

A TreeNavigator for a JavaFX scene graph.

This implementation is thread-safe in the sense that individual method calls will not fail if the scene graph is changed concurrently. But it can not prevent return values from getting stale so chaining calls might lead to unexpected results, e.g.:

 Node node = ...
 if (getParent(node).isPresent()) {
        // the node has a parent, so it should have a child index, too;
        // but the scene graph may have changed, so 'indexPresent' may be false
        boolean indexPresent = getChildIndex(node).isPresent();
 }
 

Similarly:

 Node parent = ...
 Optional<Node> child1 = getChild(parent, 0);
 Optional<Node> child2 = getChild(parent, 0);
 // if the scene graph changed between the two calls, this may be false
 boolean sameChildren = child1.equals(child2);
 

Constructor Summary

Constructors

Constructor and Description
SceneGraphNavigator()

Method Summary

Modifier and Type	Method and Description
Optional<javafx.scene.Node>	getChild(javafx.scene.Node parent, int childIndex)
OptionalInt	getChildIndex(javafx.scene.Node node)
int	getChildrenCount(javafx.scene.Node parent)
Optional<javafx.scene.Node>	getParent(javafx.scene.Node child)

Methods inherited from class java.lang.Object

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

Constructor Detail

SceneGraphNavigator

public SceneGraphNavigator()

Method Detail

getParent

public Optional<javafx.scene.Node> getParent(javafx.scene.Node child)

Specified by:

getParent in interface TreeNavigator<javafx.scene.Node>

Parameters:

child - an node in the tree

Returns:

the child's parent; if it is the root, it doesn't have a parent, so empty is returned

getChildIndex

public OptionalInt getChildIndex(javafx.scene.Node node)

Specified by:

getChildIndex in interface TreeNavigator<javafx.scene.Node>

Parameters:

node - a node in the tree

Returns:

the index of the node within the list of children of its parent; if it is the root, it doesn't have a parent, so empty is returned

getChildrenCount

public int getChildrenCount(javafx.scene.Node parent)

Specified by:

getChildrenCount in interface TreeNavigator<javafx.scene.Node>

Parameters:

parent - a node in the tree

Returns:

the number of children the node has

getChild

public Optional<javafx.scene.Node> getChild(javafx.scene.Node parent,
                                            int childIndex)

Specified by:

getChild in interface TreeNavigator<javafx.scene.Node>

Parameters:

parent - a node in the tree

childIndex - a non-negative number specifying the index of the requested child

Returns:

the child of the node with the child index; if no such child exists (e.g. because no children exist) empty is returned