org.eclipse.gef.layout.algorithms

Class TreeLayoutAlgorithm

java.lang.Object

org.eclipse.gef.layout.algorithms.TreeLayoutAlgorithm

All Implemented Interfaces:

ILayoutAlgorithm

public class TreeLayoutAlgorithm
extends java.lang.Object
implements ILayoutAlgorithm

The TreeLayoutAlgorithm class implements a simple algorithm to arrange graph nodes in a layered tree-like layout.

Field Summary

Fields

Modifier and Type	Field and Description
static int	BOTTOM_UP Tree direction constant for which root is placed at the bottom and branches spread upwards
static int	LEFT_RIGHT Tree direction constant for which root is placed at the left and branches spread to the right
static int	RIGHT_LEFT Tree direction constant for which root is placed at the right and branches spread to the left
static int	TOP_DOWN Tree direction constant for which root is placed at the top and branches spread downwards

Constructor Summary

Constructors

Constructor and Description
TreeLayoutAlgorithm() Create a default Tree Layout.
TreeLayoutAlgorithm(int direction) Create a Tree Layout with a specified direction.
TreeLayoutAlgorithm(int direction, Dimension nodeSpace) Create a Tree Layout with fixed size spacing around nodes.

Method Summary

Modifier and Type	Method and Description
void	applyLayout(LayoutContext layoutContext, boolean clean) Makes this algorithm perform layout computation and apply it to its context.
int	getDirection() Returns the direction of this TreeLayoutAlgorithm.
boolean	isResizing()
void	setDirection(int direction) Changes the direction of this TreeLayoutAlgorithm to the given value.
void	setNodeSpace(Dimension nodeSpace)
void	setResizing(boolean resizing)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

TOP_DOWN

public static final int TOP_DOWN

Tree direction constant for which root is placed at the top and branches spread downwards

See Also:

Constant Field Values

BOTTOM_UP

public static final int BOTTOM_UP

Tree direction constant for which root is placed at the bottom and branches spread upwards

See Also:

Constant Field Values

LEFT_RIGHT

public static final int LEFT_RIGHT

Tree direction constant for which root is placed at the left and branches spread to the right

See Also:

Constant Field Values

RIGHT_LEFT

public static final int RIGHT_LEFT

Tree direction constant for which root is placed at the right and branches spread to the left

See Also:

Constant Field Values

Constructor Detail

TreeLayoutAlgorithm

public TreeLayoutAlgorithm()

Create a default Tree Layout.

TreeLayoutAlgorithm

public TreeLayoutAlgorithm(int direction)

Create a Tree Layout with a specified direction.

Parameters:

direction - The direction, one of BOTTOM_UP, LEFT_RIGHT, RIGHT_LEFT, TOP_DOWN

TreeLayoutAlgorithm

public TreeLayoutAlgorithm(int direction,
                           Dimension nodeSpace)

Create a Tree Layout with fixed size spacing around nodes. If nodeSpace is not null, the layout will size the container to the ideal space to just contain all nodes of fixed size without any overlap. Otherwise, the algorithm will size for the container's available space.

Parameters:

direction - The direction, one of BOTTOM_UP, LEFT_RIGHT, RIGHT_LEFT, TOP_DOWN

nodeSpace - the size to make each node. May be null.

Method Detail

setNodeSpace

public void setNodeSpace(Dimension nodeSpace)

Parameters:

nodeSpace - the nodeSpace size to set

getDirection

public int getDirection()

Returns the direction of this TreeLayoutAlgorithm.

Returns:

The direction of this TreeLayoutAlgorithm.

setDirection

public void setDirection(int direction)

Changes the direction of this TreeLayoutAlgorithm to the given value. The direction may either be TOP_DOWN, BOTTOM_UP, LEFT_RIGHT, or RIGHT_LEFT.

Parameters:

direction - The new direction for this TreeLayoutAlgorithm.

isResizing

public boolean isResizing()

Returns:

true if this algorithm is set to resize elements

setResizing

public void setResizing(boolean resizing)

Parameters:

resizing - true if this algorithm should resize elements (default is false)

applyLayout

public void applyLayout(LayoutContext layoutContext,
                        boolean clean)

Description copied from interface: ILayoutAlgorithm

Makes this algorithm perform layout computation and apply it to its context.

Specified by:

applyLayout in interface ILayoutAlgorithm

Parameters:

layoutContext - The LayoutContext that provides all relevant information about what to layout.

clean - if true the receiver should assume that the layout context has changed significantly and recompute the whole layout even if it keeps track of changes with listeners. False can be used after dynamic layout in a context is turned back on so that layout algorithm working in background can apply accumulated changes. Static layout algorithm can ignore this call entirely if clean is false.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object