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:

Layout<V,E>, IterativeContext, org.apache.commons.collections15.Transformer<V,Point2D>

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

DAGLayout(Graph<V,E> g)
Creates an instance for the specified graph.

Method Summary

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(Graph<V,E> g) 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) Sets the dimensions of the available space for layout to size.

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

DAGLayout

public DAGLayout(Graph<V,E> g)

Creates an instance for the specified graph.

Method Detail

setRoot

public void setRoot(Graph<V,E> g)

setRoot calculates the level of each vertex in the graph. Level 0 is allocated to any 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.

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 -

setSize

public void setSize(Dimension size)

Description copied from class: SpringLayout

Sets the dimensions of the available space for layout to size.

Specified by:

setSize in interface Layout<V,E>

Overrides:

setSize in class SpringLayout<V,E>

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>

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>

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>

relaxEdges

protected void relaxEdges()

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

Overrides:

relaxEdges in class SpringLayout<V,E>