OSID - osid.topology.Edge Service Interface Definition

Interface	osid.topology.Edge
Implements	`osid.OsidRelationship`
Description	A `Edge` represents relationship between two nodes.
Method	isDirectional
Description	Tests if this is a directional edge.
Return	`boolean`		`true` if this edge is directional, `false` otherwise
Compliance	`mandatory`		This method must be implemented.
Method	isBiDirectional
Description	Tests if this directional edge is bi-directional.
Return	`boolean`		`true` if this edge is directional and bi-directional, `false` otherwise
Errors	ILLEGAL_STATE		`isDirectional()` is `false`
Compliance	`mandatory`		This method must be implemented.
Method	getCost
Description	Gets the cost of this edge.
Return	`decimal`		a number representing the cost of this edge
Compliance	`mandatory`		This method must be implemented.
Method	getDistance
Description	Gets the distance of this edge.
Return	`decimal`		a number representing the distance of this edge
Compliance	`mandatory`		This method must be implemented.
Method	getSourceNodeId
Description	Gets the source node of this edge. If the edge is uni-directional, the source node is the node at the beginning of the edge, otherwise it may be relative to the means of traversal of the graph.
Return	`osid.id.Id`		the source node `Id`
Compliance	`mandatory`		This method must be implemented.
Method	getSourceNode
Description	Gets the `Id` of the source node of this edge. If the edge is uni-directional, the source node is the node at the beginning of the edge, otherwise it may be relative to the means of traversal of the graph.
Return	`osid.topology.Node`		the source node
Errors	OPERATION_FAILED		unable to complete request
Compliance	`mandatory`		This method must be implemented.
Method	getDestinationNodeId
Description	Gets the `Id` of the destination node of this edge. If the edge is uni-directional, the destination node is the node at the end of the edge, otherwise it may be relative to the means of traversal of the graph.
Return	`osid.id.Id`		the detsination node `Id`
Compliance	`mandatory`		This method must be implemented.
Method	getDestinationNode
Description	Gets the destination node of this edge. If the edge is uni-directional, the destination node is the node at the end of the edge, otherwise it may be relative to the means of traversal of the graph.
Return	`osid.topology.Node`		the detsination node
Errors	OPERATION_FAILED		unable to complete request
Compliance	`mandatory`		This method must be implemented.
Method	getEdgeRecord
Description	Gets the edge record corresponding to the given `Edge` record `Type.` This method is used to retrieve an object implementing the requested record. The `edgeRecordType` may be the `Type` returned in `getRecordTypes()` or any of its parents in a `Type` hierarchy where `hasRecordType(edgeRecordType)` is `true` .
Parameters	`osid.type.Type`	`edgeRecordType`	the type of edge record to retrieve
Return	`osid.topology.records.EdgeRecord`		the edge record
Errors	NULL_ARGUMENT		`edgeRecordType` is `null`
	OPERATION_FAILED		unable to complete request
	UNSUPPORTED		`hasRecordType(edgeRecordType)` is `false`
Compliance	`mandatory`		This method must be implemented.