org.codefx.libfx.collection.tree.navigate

Class ComponentHierarchyNavigator

java.lang.Object

org.codefx.libfx.collection.tree.navigate.ComponentHierarchyNavigator

All Implemented Interfaces:

TreeNavigator<Component>

public class ComponentHierarchyNavigator
extends Object
implements TreeNavigator<Component>

A TreeNavigator for an AWT component hierarchy.

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

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

Similarly:

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

Constructor Summary

Constructors

Constructor and Description
ComponentHierarchyNavigator()

Method Summary

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

Methods inherited from class java.lang.Object

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

Constructor Detail

ComponentHierarchyNavigator

public ComponentHierarchyNavigator()

Method Detail

getParent

public Optional<Component> getParent(Component child)

Specified by:

getParent in interface TreeNavigator<Component>

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(Component node)

Specified by:

getChildIndex in interface TreeNavigator<Component>

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(Component parent)

Specified by:

getChildrenCount in interface TreeNavigator<Component>

Parameters:

parent - a node in the tree

Returns:

the number of children the node has

getChild

public Optional<Component> getChild(Component parent,
                                    int childIndex)

Specified by:

getChild in interface TreeNavigator<Component>

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