Package dev.roanh.gmark.util

Class SchemaGraph

java.lang.Object

dev.roanh.gmark.util.UniqueGraph<SelectivityType,Predicate>

dev.roanh.gmark.util.SchemaGraph

public class SchemaGraph
extends UniqueGraph<SelectivityType,Predicate>

The schema graph is a graph that has selectivity types as its nodes. These nodes represent the combination of some node type and some selectivity class. There are directed labelled edges present between these selectivity type nodes. These edges indicate that it is possible to extend a path query with an edge with a certain label to end up at the target selectivity type.

See Also:

• SelectivityType
• Predicate

Nested Class Summary

Nested classes/interfaces inherited from class dev.roanh.gmark.util.UniqueGraph

UniqueGraph.GraphEdge<V,E>, UniqueGraph.GraphNode<V,E>

Field Summary

Fields

Modifier and Type	Field	Description
private RangeList<Map<SelectivityClass,UniqueGraph.GraphNode<SelectivityType,Predicate>>>	index	Efficient lookup index from selectivity type to graph node.

Constructor Summary

Constructors

Constructor	Description
SchemaGraph(Schema schema)	Constructs a new schema graph from the given schema.

Method Summary

Modifier and Type	Method	Description
void	printEdges()	Prints all the edges in the schema graph to the standard output.
void	printNodes()	Prints all the nodes in the schema graph to the standard output.
void	removeUnreachable()	Removes all nodes (and associated edges) from the schema graph that are not reachable when drawing paths.
private UniqueGraph.GraphNode<SelectivityType,Predicate>	resolve(Type type, SelectivityClass sel)	Resolves the given selectivity type presented as a type and selectivity class to the associated graph node adding a new node if required.

Methods inherited from class dev.roanh.gmark.util.UniqueGraph

addUniqueEdge, addUniqueEdge, addUniqueEdge, addUniqueEdge, addUniqueEdge, addUniqueEdge, addUniqueEdge, addUniqueEdge, addUniqueNode, copy, getEdge, getEdge, getEdgeCount, getEdges, getNode, getNodeCount, getNodes, removeNodeIf, toAdjacencyList

Methods inherited from class java.lang.Object

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

Field Details

index

private RangeList<Map<SelectivityClass,UniqueGraph.GraphNode<SelectivityType,Predicate>>> index

Efficient lookup index from selectivity type to graph node.

Constructor Details

SchemaGraph

public SchemaGraph(Schema schema)

Constructs a new schema graph from the given schema.

Parameters:

schema - The graph schema to build the schema graph from.

Method Details

resolve

private UniqueGraph.GraphNode<SelectivityType,Predicate> resolve(Type type,
 SelectivityClass sel)

Resolves the given selectivity type presented as a type and selectivity class to the associated graph node adding a new node if required.

Parameters:

type - The type of the selectivity type.

sel - The selectivity of the selectivity type.

Returns:

The graph node associated with the given selectivity type.

removeUnreachable

public void removeUnreachable()

Removes all nodes (and associated edges) from the schema graph that are not reachable when drawing paths. All valid paths should start at a node with a selectivity class of SelectivityClass.ONE_ONE or SelectivityClass.EQUALS. Any node that is not reachable from a node with one of these selectivity classes is removed together with all the edges connected to it.

printNodes

public void printNodes()

Prints all the nodes in the schema graph to the standard output.

printEdges

public void printEdges()

Prints all the edges in the schema graph to the standard output.