com.yworks.yfiles.layout.hierarchic

Class DefaultLayerSequencer

java.lang.Object

com.yworks.yfiles.layout.hierarchic.DefaultLayerSequencer

All Implemented Interfaces:

ISequencer

public class DefaultLayerSequencer
extends Object
implements ISequencer

This class is a ISequencer implementation that performs the second phase of the Sugiyama algorithm.

It minimizes the crossings in the diagram by using either the barycentric or median heuristic.

Constructor Summary

Constructors

Constructor and Description
DefaultLayerSequencer() Creates a new instance of DefaultLayerSequencer.

Method Summary

Modifier and Type	Method and Description
long	getMaximumDuration() Gets the time limit (in milliseconds) set for this sequencer per execution.
int	getRandomizationRounds() Gets the number of randomized rounds that this algorithm performs, if there was no optimal solution.
WeightHeuristic	getWeightHeuristic() Gets the weight heuristic that should be used.
boolean	isGroupTransposition() Gets whether or not an additional crossing minimization heuristic should be used in the presence of grouped graphs.
boolean	isTransposition() Gets whether or not to apply an additional crossing minimization heuristic.
void	sequenceNodeLayers(LayoutGraph graph, ILayers glayers, ILayoutDataProvider ldp, IItemFactory itemFactory) Calculates the sequence of the nodes within each layer.
void	setGroupTransposition(boolean value) Sets whether or not an additional crossing minimization heuristic should be used in the presence of grouped graphs.
void	setMaximumDuration(long value) Sets the time limit (in milliseconds) set for this sequencer per execution.
void	setRandomizationRounds(int value) Sets the number of randomized rounds that this algorithm performs, if there was no optimal solution.
void	setTransposition(boolean value) Sets whether or not to apply an additional crossing minimization heuristic.
void	setWeightHeuristic(WeightHeuristic value) Sets the weight heuristic that should be used.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultLayerSequencer

public DefaultLayerSequencer()

Creates a new instance of DefaultLayerSequencer.

Method Detail

getMaximumDuration

public long getMaximumDuration()

Gets the time limit (in milliseconds) set for this sequencer per execution.

Values have to be greater than or equal to 0.

Throws:

IllegalArgumentException - if the maximum duration is negative.

Default Value:

The default value is 10000.

Returns:

a non-negative value that specifies the time limit

See Also:

setMaximumDuration(long)

getRandomizationRounds

public int getRandomizationRounds()

Gets the number of randomized rounds that this algorithm performs, if there was no optimal solution.

Values have to be greater than or equal to 0.

Throws:

IllegalArgumentException - if a negative value is given

Default Value:

The default value is 50. The number of randomized rounds is 50, if the maximum duration hasn't been reduced below its default value. Otherwise, 14 rounds are performed.

Returns:

the number of additional rounds

See Also:

setRandomizationRounds(int)

getWeightHeuristic

public WeightHeuristic getWeightHeuristic()

Gets the weight heuristic that should be used.

Throws:

IllegalArgumentException - if the constant is unknown

Default Value:

The default value is WeightHeuristic.BARYCENTER. A barycenter heuristic is used.

Returns:

one of the predefined weight heuristics

See Also:

setWeightHeuristic(WeightHeuristic)

isGroupTransposition

public boolean isGroupTransposition()

Gets whether or not an additional crossing minimization heuristic should be used in the presence of grouped graphs.

Activating this heuristic can reduce the overall number of edge crossings in grouped graphs. On the other hand, it may increase running time.

Default Value:

The default value is false. The group transposition rule is disabled.

Returns:

true if the crossing minimization heuristic should be applied, false otherwise

See Also:

setGroupTransposition(boolean)

isTransposition

public boolean isTransposition()

Gets whether or not to apply an additional crossing minimization heuristic.

Activating this heuristic can reduce the overall number of edge crossings. On the other hand, it may increase the running time.

Default Value:

The default value is true. The transposition rule is active.

Returns:

true if the crossing minimization heuristic is applied, false otherwise

See Also:

setTransposition(boolean)

sequenceNodeLayers

public void sequenceNodeLayers(LayoutGraph graph,
                               ILayers glayers,
                               ILayoutDataProvider ldp,
                               IItemFactory itemFactory)

Description copied from interface: ISequencer

Calculates the sequence of the nodes within each layer.

This method is called by HierarchicLayoutCore during the second phase and finally writes back the calculated sequence using the ILayer.setNodeOrder(com.yworks.yfiles.algorithms.YList) method.

Specified by:

sequenceNodeLayers in interface ISequencer

Parameters:

graph - the input graph

glayers - the given ILayers instance containing the elements in the layering

ldp - the ILayoutDataProvider implementation which provides access to the INodeData and IEdgeData instances

itemFactory - the IItemFactory used temporarily for modifying the graph instance

setGroupTransposition

public void setGroupTransposition(boolean value)

Sets whether or not an additional crossing minimization heuristic should be used in the presence of grouped graphs.

Activating this heuristic can reduce the overall number of edge crossings in grouped graphs. On the other hand, it may increase running time.

Default Value:

The default value is false. The group transposition rule is disabled.

Parameters:

value - true if the crossing minimization heuristic should be applied, false otherwise

See Also:

isGroupTransposition()

setMaximumDuration

public void setMaximumDuration(long value)

Sets the time limit (in milliseconds) set for this sequencer per execution.

Values have to be greater than or equal to 0.

Throws:

IllegalArgumentException - if the maximum duration is negative.

Default Value:

The default value is 10000.

Parameters:

value - a non-negative value that specifies the time limit

See Also:

getMaximumDuration()

setRandomizationRounds

public void setRandomizationRounds(int value)

Sets the number of randomized rounds that this algorithm performs, if there was no optimal solution.

Values have to be greater than or equal to 0.

Throws:

IllegalArgumentException - if a negative value is given

Default Value:

The default value is 50. The number of randomized rounds is 50, if the maximum duration hasn't been reduced below its default value. Otherwise, 14 rounds are performed.

Parameters:

value - the number of additional rounds

See Also:

getRandomizationRounds()

setTransposition

public void setTransposition(boolean value)

Sets whether or not to apply an additional crossing minimization heuristic.

Activating this heuristic can reduce the overall number of edge crossings. On the other hand, it may increase the running time.

Default Value:

The default value is true. The transposition rule is active.

Parameters:

value - true if the crossing minimization heuristic is applied, false otherwise

See Also:

isTransposition()

setWeightHeuristic

public void setWeightHeuristic(WeightHeuristic value)

Sets the weight heuristic that should be used.

Throws:

IllegalArgumentException - if the constant is unknown

Default Value:

The default value is WeightHeuristic.BARYCENTER. A barycenter heuristic is used.

Parameters:

value - one of the predefined weight heuristics

See Also:

getWeightHeuristic()