y.layout
Class LayoutMultiplexer

java.lang.Object
  y.layout.AbstractLayoutStage
      y.layout.LayoutMultiplexer

All Implemented Interfaces:

Layouter, LayoutStage

public class LayoutMultiplexer
extends AbstractLayoutStage

A LayoutMultiplexer delegates its layout calls to a core layout algorithm that is dynamically chosen at runtime by inspecting the nodes of the input graph.

If a DataProvider is registered with the given graph using the look-up key LAYOUTER_DPKEY, it is used for retrieving the Layouter objects that are stored for the graph's nodes. If no such DataProvider is registered, this layout stage's core layout algorithm (if any) is used for the layout calculation of all nodes.

Note that the first non-null Layouter instance retrieved from the DataProvider is used for all nodes.

The main purpose of this class is to enable the use of individual layout algorithms for different components (when used as the core layout algorithm of ComponentLayouter) or for the contents of group nodes (when used as the core layout algorithm of RecursiveGroupLayouter).

Field Summary

static java.lang.Object

LAYOUTER_DPKEY A DataProvider key for assigning layout algorithms to the nodes At runtime, the layout algorithms are determined and applied to the current graph.

Fields inherited from interface y.layout.Layouter

EDGE_ID_DPKEY, NODE_ID_DPKEY, NODE_TYPE_DPKEY, SELECTED_EDGES, SELECTED_NODES

Constructor Summary

LayoutMultiplexer()
Creates a new instance of LayoutMultiplexer.

Method Summary

boolean	canLayout(LayoutGraph graph) Accepts all general graphs.
void	doLayout(LayoutGraph graph) Retrieves and invokes the layout algorithm that is assigned to the graph.
protected Layouter	getCoreLayouter(LayoutGraph graph) Returns the core layout algorithm associated with the nodes contained in the given graph.

Methods inherited from class y.layout.AbstractLayoutStage

canLayoutCore, doLayoutCore, getCoreLayouter, setCoreLayouter

Methods inherited from class java.lang.Object

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

Field Detail

LAYOUTER_DPKEY

public static final java.lang.Object LAYOUTER_DPKEY

A DataProvider key for assigning layout algorithms to the nodes

At runtime, the layout algorithms are determined and applied to the current graph. The first non-null Layouter instance is used for the whole graph.

Constructor Detail

LayoutMultiplexer

public LayoutMultiplexer()

Creates a new instance of LayoutMultiplexer.

Method Detail

canLayout

public boolean canLayout(LayoutGraph graph)

Accepts all general graphs.

Parameters:

graph - the input graph

Returns:

true if the graph is not null, false otherwise

See Also:

Layouter.doLayout(LayoutGraph)

doLayout

public void doLayout(LayoutGraph graph)

Retrieves and invokes the layout algorithm that is assigned to the graph.

Parameters:

graph - the input graph

See Also:

Layouter.canLayout(LayoutGraph)

getCoreLayouter

protected Layouter getCoreLayouter(LayoutGraph graph)

Returns the core layout algorithm associated with the nodes contained in the given graph.

This implementation looks up the layout algorithm in the DataProvider registered with the key LAYOUTER_DPKEY. The first non-null layout algorithm instance found for a node of the given graph will be returned by this method. If no algorithm is registered at all, it will fall back to the default core layout algorithm.

This method is called in doLayout(LayoutGraph) and may be overridden to implement a different way of selecting the layout algorithms.

Parameters:

graph - the input graph

Returns:

the according layout algorithm