edu.uci.ics.jung.algorithms.layout

Class DAGLayout<V,E>

java.lang.Object

edu.uci.ics.jung.algorithms.layout.AbstractLayout<V,E>

edu.uci.ics.jung.algorithms.layout.SpringLayout<V,E>

edu.uci.ics.jung.algorithms.layout.DAGLayout<V,E>

All Implemented Interfaces:

com.google.common.base.Function<V,Point2D>, Layout<V,E>, IterativeContext

public class DAGLayout<V,E>
extends SpringLayout<V,E>

An implementation of Layout suitable for tree-like directed acyclic graphs. Parts of it will probably not terminate if the graph is cyclic! The layout will result in directed edges pointing generally upwards. Any vertices with no successors are considered to be level 0, and tend towards the top of the layout. Any vertex has a level one greater than the maximum level of all its successors.

Author:

John Yesberg

Nested Class Summary

Nested classes/interfaces inherited from class edu.uci.ics.jung.algorithms.layout.SpringLayout

SpringLayout.SpringDimensionChecker, SpringLayout.SpringVertexData

Field Summary

Fields inherited from class edu.uci.ics.jung.algorithms.layout.SpringLayout

force_multiplier, lengthFunction, repulsion_range_sq, springVertexData, stretch

Fields inherited from class edu.uci.ics.jung.algorithms.layout.AbstractLayout

graph, initialized, locations, size

Constructor Summary

Constructors

Constructor and Description
DAGLayout(Graph<V,E> g)

Method Summary

Modifier and Type	Method and Description
boolean	done() Override incrementsAreDone so that we can eventually stop.
void	initialize() Had to override this one as well, to ensure that setRoot() is called.
protected void	moveNodes() Override the moveNodes() method from SpringLayout.
void	propagateMinimumLevel(V v) A recursive method for allocating the level for each vertex.
protected void	relaxEdges() Overridden relaxEdges.
void	setLocation(V picked, double x, double y) Override forceMove so that if someone moves a node, we can re-layout everything.
void	setLocation(V picked, Point2D p) Override forceMove so that if someone moves a node, we can re-layout everything.
void	setRoot() Calculates the level of each vertex in the graph.
void	setRoot(V v) Set vertex v to be level 0.
void	setSize(Dimension size) When a visualization is resized, it presumably wants to fix the locations of the vertices and possibly to reinitialize its data.

Methods inherited from class edu.uci.ics.jung.algorithms.layout.SpringLayout

calculateRepulsion, getForceMultiplier, getRepulsionRange, getStretch, isIncremental, reset, setForceMultiplier, setRepulsionRange, setStretch, step

Methods inherited from class edu.uci.ics.jung.algorithms.layout.AbstractLayout

apply, getGraph, getSize, getX, getY, isLocked, lock, lock, offsetVertex, setGraph, setInitializer

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.google.common.base.Function

equals

Constructor Detail

DAGLayout

public DAGLayout(Graph<V,E> g)

Method Detail

setRoot

public void setRoot()

Calculates the level of each vertex in the graph. Level 0 is allocated to each vertex with no successors. Level n+1 is allocated to any vertex whose successors' maximum level is n.

setRoot

public void setRoot(V v)

Set vertex v to be level 0.

Parameters:

v - the vertex to set as root

propagateMinimumLevel

public void propagateMinimumLevel(V v)

A recursive method for allocating the level for each vertex. Ensures that all predecessors of v have a level which is at least one greater than the level of v.

Parameters:

v - the vertex whose minimum level is to be calculated

setSize

public void setSize(Dimension size)

Description copied from class: AbstractLayout

When a visualization is resized, it presumably wants to fix the locations of the vertices and possibly to reinitialize its data. The current method calls initializeLocations followed by initialize_local.

Specified by:

setSize in interface Layout<V,E>

Overrides:

setSize in class SpringLayout<V,E>

Parameters:

size - the space to use to lay out this graph

initialize

public void initialize()

Had to override this one as well, to ensure that setRoot() is called.

Specified by:

initialize in interface Layout<V,E>

Overrides:

initialize in class SpringLayout<V,E>

moveNodes

protected void moveNodes()

Override the moveNodes() method from SpringLayout. The only change we need to make is to make sure that nodes don't float higher than the minY coordinate, as calculated by their minimumLevel.

Overrides:

moveNodes in class SpringLayout<V,E>

done

public boolean done()

Override incrementsAreDone so that we can eventually stop.

Specified by:

done in interface IterativeContext

Overrides:

done in class SpringLayout<V,E>

Returns:

false

setLocation

public void setLocation(V picked,
                        double x,
                        double y)

Override forceMove so that if someone moves a node, we can re-layout everything.

Overrides:

setLocation in class AbstractLayout<V,E>

Parameters:

picked - the vertex whose location is to be set

x - the x coordinate of the location to set

y - the y coordinate of the location to set

setLocation

public void setLocation(V picked,
                        Point2D p)

Override forceMove so that if someone moves a node, we can re-layout everything.

Specified by:

setLocation in interface Layout<V,E>

Overrides:

setLocation in class AbstractLayout<V,E>

Parameters:

picked - the vertex whose location is to be set

p - the location to set

relaxEdges

protected void relaxEdges()

Overridden relaxEdges. This one reduces the effect of edges between greatly different levels.

Overrides:

relaxEdges in class SpringLayout<V,E>