y.layout.router
Class BusRepresentations

java.lang.Object
  y.layout.router.BusRepresentations

public class BusRepresentations
extends java.lang.Object

This class provides helper methods to convert between buses given by complete subgraphs and buses represented by specific hub nodes.

In a representation by means of hubs, each connected subgraph induced by hubs establishes a bus. All regular nodes (non-hubs) which are connected to hubs of the same component are end-nodes of the same bus. In other words, nodes which are reachable on paths consisting of only hubs belong to the same bus. Of course, a node can be an end-node of more than one bus.

Since a bus models a group of nodes in which every node is connected to every other node, it can be represented as a complete subgraph of these nodes. To distinguish buses in this representation, each edge must be associated with a unique ID which identifies the bus to which it is associated. This is the representation expected by BusRouter.

Field Summary

static java.lang.Object	SOURCE_ID_DPKEY A DataAcceptor key to transfer a user-defined object from each original edge to the respective newly created edge Since there is no one-to-one mapping between original and new edges, the data provider of this key is responsible for the edges whose source endpoint is a regular node.
static java.lang.Object	TARGET_ID_DPKEY A DataAcceptor key to transfer a user-defined object from each original edge to the respective newly created edge Since there is no one-to-one mapping between original and new edges, the data provider of this key is responsible for the edges whose target endpoint is a regular node.

Method Summary

static EdgeList	replaceHubsBySubgraph(LayoutGraph graph, DataProvider hubMarker, DataAcceptor descriptorAcceptor) Changes the representation of buses from hubs to complete subgraphs.
static EdgeList	replaceHubsBySubgraph(LayoutGraph graph, EdgeList[] hubEdgesLists, DataProvider hubMarker, DataProvider fixedMarker, DataAcceptor descriptorAcceptor) Changes the representation of buses from hubs to complete subgraphs by creating new edges between regular nodes and removing the hubs.
static void	replaceSubgraphByHubs(LayoutGraph graph, EdgeCursor edgeCursor, DataProvider descriptorProvider, DataAcceptor busIDAcceptor) Changes the representation of buses from complete subgraphs to hubs by replacing intersection points by hubs.
static EdgeList[]	toEdgeLists(Graph graph, DataProvider hubMarker) Calculates for every bus represented by hubs a list of all of its edges.

Methods inherited from class java.lang.Object

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

Field Detail

SOURCE_ID_DPKEY

public static final java.lang.Object SOURCE_ID_DPKEY

A DataAcceptor key to transfer a user-defined object from each original edge to the respective newly created edge

Since there is no one-to-one mapping between original and new edges, the data provider of this key is responsible for the edges whose source endpoint is a regular node.

TARGET_ID_DPKEY

public static final java.lang.Object TARGET_ID_DPKEY

A DataAcceptor key to transfer a user-defined object from each original edge to the respective newly created edge

Since there is no one-to-one mapping between original and new edges, the data provider of this key is responsible for the edges whose target endpoint is a regular node.

Method Detail

toEdgeLists

public static EdgeList[] toEdgeLists(Graph graph,
                                     DataProvider hubMarker)

Calculates for every bus represented by hubs a list of all of its edges.

This method cannot return isolated hubs.

Parameters:

graph - the graph where buses are represented by means of hubs

hubMarker - a DataProvider which marks hub nodes

Returns:

an array of EdgeLists where each list contains all edges of a bus

replaceHubsBySubgraph

public static EdgeList replaceHubsBySubgraph(LayoutGraph graph,
                                             DataProvider hubMarker,
                                             DataAcceptor descriptorAcceptor)

Changes the representation of buses from hubs to complete subgraphs. This method delegates to replaceHubsBySubgraph(LayoutGraph, EdgeList[], DataProvider, DataProvider, DataAcceptor).

Parameters:

graph - the graph of the bus

hubMarker - a DataProvider that marks hub nodes

descriptorAcceptor - a DataAcceptor for storing the created bus descriptors

Returns:

a list of the created edges

See Also:

replaceHubsBySubgraph(LayoutGraph, EdgeList[], DataProvider, DataProvider, DataAcceptor), toEdgeLists(Graph, DataProvider)

replaceHubsBySubgraph

public static EdgeList replaceHubsBySubgraph(LayoutGraph graph,
                                             EdgeList[] hubEdgesLists,
                                             DataProvider hubMarker,
                                             DataProvider fixedMarker,
                                             DataAcceptor descriptorAcceptor)

Changes the representation of buses from hubs to complete subgraphs by creating new edges between regular nodes and removing the hubs.

This method respects multiple connections of nodes and creates appropriate BusDescriptors consisting of the bus ID as well as source and target group IDs.

The path of each new edge follows the route defined by the component of the hubs. If the subgraph of hubs is not a tree, these paths are ambiguous. In this case, an arbitrary tree is computed from the hub's subgraph which defines all the paths.

Parameters:

graph - the graph of the bus

hubEdgesLists - an array of EdgeLists each containing the edges of a bus

hubMarker - a DataProvider that marks hub nodes

fixedMarker - a DataProvider that marks fixed edges

descriptorAcceptor - a DataAcceptor for storing the created bus descriptors

Returns:

a list of the created edges

replaceSubgraphByHubs

public static void replaceSubgraphByHubs(LayoutGraph graph,
                                         EdgeCursor edgeCursor,
                                         DataProvider descriptorProvider,
                                         DataAcceptor busIDAcceptor)

Changes the representation of buses from complete subgraphs to hubs by replacing intersection points by hubs.

The edges of the given graph must form an orthogonal, cycle-free bus, otherwise an IllegalStateException is thrown.

Parameters:

graph - the graph where each bus is represented by a complete subgraph of the corresponding nodes

edgeCursor - an EdgeCursor of the regular edges

descriptorProvider - a DataProvider that provides a BusDescriptor for each edge

busIDAcceptor - an optional DataAcceptor that stores the bus ID for each new edge

Throws:

java.lang.IllegalStateException - if the path of an edge is not orthogonal or if some paths form a cycle