Package org.eclipse.gef.layout.algorithms

Class TreeLayoutHelper

java.lang.Object

org.eclipse.gef.layout.algorithms.TreeLayoutHelper

public class TreeLayoutHelper
extends Object

A helper class for layout algorithms that are based on tree structure. It keeps track of changes in observed layout context and stores current information about the tree structure - children of each node and several other parameters.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	TreeLayoutHelper.TreeListener	A superclass for listeners that can be added to this observer to get notification whenever the tree structure changes.
static class	TreeLayoutHelper.TreeNode	Represents a node in a tree structure and stores all information related to it.
static class	TreeLayoutHelper.TreeNodeFactory	TreeLayoutObserver uses instance of this class to create instances of TreeLayoutHelper.TreeNode.

Constructor Summary

Constructors

Constructor	Description
TreeLayoutHelper(TreeLayoutHelper.TreeNodeFactory nodeFactory)	Constructs a new TreeLayoutHelper for observing the given LayoutContext.

Method Summary

Modifier and Type	Method	Description
void	computeTree(org.eclipse.gef.graph.Node[] nodes)	Recomputes all the information about the tree structure (the same effect as creating new TreeLayoutObserver).
protected TreeLayoutHelper.TreeNode	getSuperRoot()	Returns Super Root, that is an artificial node being a common parent for all nodes in observed tree structure.
protected TreeLayoutHelper.TreeNode	getTreeNode(org.eclipse.gef.graph.Node node)	Returns a TreeLayoutHelper.TreeNode related to given node layout.

Methods inherited from class java.lang.Object

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

Constructor Details

TreeLayoutHelper

public TreeLayoutHelper(TreeLayoutHelper.TreeNodeFactory nodeFactory)

Constructs a new TreeLayoutHelper for observing the given LayoutContext. The given TreeLayoutHelper.TreeNodeFactory will be used for the construction of TreeLayoutHelper.TreeNodes. If no factory is supplied, the TreeLayoutHelper.TreeNodeFactory will be used.

Parameters:

nodeFactory - The TreeLayoutHelper.TreeNodeFactory to use.

Method Details

computeTree

public void computeTree(org.eclipse.gef.graph.Node[] nodes)

Recomputes all the information about the tree structure (the same effect as creating new TreeLayoutObserver).

Parameters:

nodes - nodes

getSuperRoot

protected TreeLayoutHelper.TreeNode getSuperRoot()

Returns Super Root, that is an artificial node being a common parent for all nodes in observed tree structure.

Returns:

Super Root

getTreeNode

protected TreeLayoutHelper.TreeNode getTreeNode(org.eclipse.gef.graph.Node node)

Returns a TreeLayoutHelper.TreeNode related to given node layout. If such a TreeNode doesn't exist, it's created.

Parameters:

node - The Node for which to return the corresponding TreeLayoutHelper.TreeNode.

Returns:

The already existing TreeLayoutHelper.TreeNode related to the given Node or a newly created one in case there was no related TreeLayoutHelper.TreeNode before.