Package org.apache.openjpa.lib.graph

Class Edge

java.lang.Object

org.apache.openjpa.lib.graph.Edge

public class Edge
extends Object

A graph edge. Includes the from and to nodes, an arbitrary user object, and a weight. Edges can be either directed or undirected.

Since:

1.0.0

Author:

Abe White

Field Summary

Fields

Modifier and Type	Field	Description
static int	TYPE_BACK	An edge (u, v) is a back edge if it creates a cycle back to an ancestor in the graph.
static int	TYPE_FORWARD	An edge (u, v) is a forward edge if it is not a tree or back edge.
static int	TYPE_TREE	An edge (u, v) is a tree edge if node v was first discovered by traversing the edge.

Constructor Summary

Constructors

Constructor	Description
Edge(Object from, Object to, boolean directed)	Constructor.
Edge(Object from, Object to, boolean directed, Object userObject)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	clearTraversal()	Clear traversal info.
List<Edge>	getCycle()	List of edges forming a cycle.
Object	getFrom()	Return the node the edge links from.
Object	getOther(Object node)	Return the node on the opposite end of the given one, or null if the given node is not part of this edge.
Object	getTo()	Return the node the edge links to.
int	getType()	Traversal bookkeeping info.
Object	getUserObject()	Arbitrary user object associated with the edge.
double	getWeight()	Return the weight of the edge.
boolean	isDirected()	Return whether the edge is directed.
boolean	isFrom(Object node)	Return true if this edge links from the given node.
boolean	isRemovedFromGraph()	Returns if this edge is (still) part of the graph.
boolean	isTo(Object node)	Return true if this edge links to the given node.
void	setCycle(List<Edge> cycle)	List of edges forming a cycle.
void	setRemovedFromGraph()	Mark this edge as removed from the graph.
void	setType(int type)	Traversal bookkeeping info.
void	setUserObject(Object obj)	Arbitrary user object associated with the edge.
void	setWeight(double weight)	Set the weight of the edge.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

TYPE_TREE

public static final int TYPE_TREE

An edge (u, v) is a tree edge if node v was first discovered by traversing the edge.

See Also:

Constant Field Values

TYPE_BACK

public static final int TYPE_BACK

An edge (u, v) is a back edge if it creates a cycle back to an ancestor in the graph.

See Also:

Constant Field Values

TYPE_FORWARD

public static final int TYPE_FORWARD

An edge (u, v) is a forward edge if it is not a tree or back edge.

See Also:

Constant Field Values

Constructor Detail

Edge

public Edge(Object from,
            Object to,
            boolean directed)

Constructor.

Parameters:

from - the node the edge comes from

to - the node the edge goes to

directed - whether the edge is directed

Edge

public Edge(Object from,
            Object to,
            boolean directed,
            Object userObject)

Constructor.

Parameters:

from - the node the edge comes from

to - the node the edge goes to

directed - whether the edge is directed

userObject - an associated object

Method Detail

getFrom

public Object getFrom()

Return the node the edge links from.

getTo

public Object getTo()

Return the node the edge links to.

getOther

public Object getOther(Object node)

Return the node on the opposite end of the given one, or null if the given node is not part of this edge.

isTo

public boolean isTo(Object node)

Return true if this edge links to the given node. For undirected edges, this method returns true if either side is equal to the given node.

isFrom

public boolean isFrom(Object node)

Return true if this edge links from the given node. For undirected edges, this method returns true if either side is equal to the given node.

isDirected

public boolean isDirected()

Return whether the edge is directed.

getWeight

public double getWeight()

Return the weight of the edge.

setWeight

public void setWeight(double weight)

Set the weight of the edge.

getUserObject

public Object getUserObject()

Arbitrary user object associated with the edge.

setUserObject

public void setUserObject(Object obj)

Arbitrary user object associated with the edge.

getType

public int getType()

Traversal bookkeeping info.

setType

public void setType(int type)

Traversal bookkeeping info.

getCycle

public List<Edge> getCycle()

List of edges forming a cycle. Only set for TYPE_BACK and TYPE_FORWARD edges.

setCycle

public void setCycle(List<Edge> cycle)

List of edges forming a cycle. Only set for TYPE_BACK and TYPE_FORWARD edges.

isRemovedFromGraph

public boolean isRemovedFromGraph()

Returns if this edge is (still) part of the graph.

setRemovedFromGraph

public void setRemovedFromGraph()

Mark this edge as removed from the graph.

clearTraversal

public void clearTraversal()

Clear traversal info.

toString

public String toString()

Overrides:

toString in class Object