com.redhat.lightblue.assoc

Class QueryPlan

java.lang.Object

com.redhat.lightblue.assoc.QueryPlan

All Implemented Interfaces:

Serializable

public class QueryPlan
extends Object
implements Serializable

Represents a query plan. A query plan is constructed from composite metadata. Starting from the root entity, a QueryPlanNode is created in the query plan for each entity in the composite metadata. Query plan is initially constructed using the same tree structure as the metadata, but query plan offers flip operation to change the direction of an edge in the tree. During query plan determination, many query plans are evaluated, and an efficient one is selected, so this implementation of QueryPlan is optimized for quickly evaluating flip operations, and quickly creating a clone of the query plan. The internal representation is a connection matrix between the nodes. These are the internal fields:

• nodes: Query plan nodes in an array. Each node contains a nodeIndex such that nodes[i].nodeIndex=i
• connMx: Connection matrix. If connMx[from][to]=true, then there is an edge from nodes[from] to nodes[to]
• fromN: fromN[i]=number of edges emanating from nodes[i]
• toN: toN[i]=number of edges entering into nodes[i]

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
QueryPlan(CompositeMetadata root, QueryPlanScorer qdf) Constructs a query plan from the composite metadata by recursively descending through the associated entities, and creating a node for every entity.
QueryPlan(CompositeMetadata root, QueryPlanScorer qdf, Set<CompositeMetadata> filter) Constructs a query plan from the composite metadata by recursively descending through the associated entities as deterimed by the filter, and creating a node for every entity.

Method Summary

Methods

Modifier and Type	Method and Description
void	connect(QueryPlanNode from, QueryPlanNode to) Connects two nodes
QueryPlan	deepCopy() Returns a deep copy of the query plan.
void	flip(QueryPlanNode x, QueryPlanNode y) Flips the direction of a node.
QueryPlanNode[]	getAllNodes() Returns all nodes
QueryPlanNode[]	getBreadthFirstNodeOrdering()
QueryPlanData	getEdgeData(QueryPlanNode x, QueryPlanNode y) Returns the list of conjuncts associated with the undirected edge between the two nodes
QueryPlanNode	getNode(CompositeMetadata md) Returns the query plan node corresponding to the given composite metadata instance.
int	getSize() Returns the size (number of nodes) of the query plan
QueryPlanNode[]	getSources() Returns an array of source nodes, nodes with no incoming edges.
List<Conjunct>	getUnassignedClauses() Returns the list containing clauses that cannot be associated with a node or an edge (i.e.
boolean	isDirectedConnected(QueryPlanNode from, QueryPlanNode to) Returns if there exists a directed edge between the nodes, directed from from to to
boolean	isUndirectedConnected(QueryPlanNode from, QueryPlanNode to) Returns if there exists an edge between the two nodes, pointing either way
String	mxToString()
QueryPlanData	newData() Creates a new instance of QueryPlanData
void	setEdgeData(QueryPlanNode x, QueryPlanNode y, QueryPlanData d) Sets the list of conjuncts associated with the undirected edge between the two nodes
String	toString()
String	treeToString()
StringBuilder	treeToString(StringBuilder bld)

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryPlan

public QueryPlan(CompositeMetadata root,
         QueryPlanScorer qdf)

Constructs a query plan from the composite metadata by recursively descending through the associated entities, and creating a node for every entity.

QueryPlan

public QueryPlan(CompositeMetadata root,
         QueryPlanScorer qdf,
         Set<CompositeMetadata> filter)

Constructs a query plan from the composite metadata by recursively descending through the associated entities as deterimed by the filter, and creating a node for every entity.

Parameters:

root - The root composite metadata

qdf - The scorer

filter - A set of composite metadata objects containing only those entities that should be included in the plan. If null, all entities will be included.

Method Detail

getSize

public int getSize()

Returns the size (number of nodes) of the query plan

newData

public QueryPlanData newData()

Creates a new instance of QueryPlanData

getSources

public QueryPlanNode[] getSources()

Returns an array of source nodes, nodes with no incoming edges. This can never return null, or an empty array. Worst case, it will return the root entity.

getUnassignedClauses

public List<Conjunct> getUnassignedClauses()

Returns the list containing clauses that cannot be associated with a node or an edge (i.e. clauses refer to more than two nodes).

getEdgeData

public QueryPlanData getEdgeData(QueryPlanNode x,
                        QueryPlanNode y)

Returns the list of conjuncts associated with the undirected edge between the two nodes

setEdgeData

public void setEdgeData(QueryPlanNode x,
               QueryPlanNode y,
               QueryPlanData d)

Sets the list of conjuncts associated with the undirected edge between the two nodes

deepCopy

public QueryPlan deepCopy()

Returns a deep copy of the query plan.

flip

public void flip(QueryPlanNode x,
        QueryPlanNode y)

Flips the direction of a node.

connect

public void connect(QueryPlanNode from,
           QueryPlanNode to)

Connects two nodes

getAllNodes

public QueryPlanNode[] getAllNodes()

Returns all nodes

isDirectedConnected

public boolean isDirectedConnected(QueryPlanNode from,
                          QueryPlanNode to)

Returns if there exists a directed edge between the nodes, directed from from to to

isUndirectedConnected

public boolean isUndirectedConnected(QueryPlanNode from,
                            QueryPlanNode to)

Returns if there exists an edge between the two nodes, pointing either way

getBreadthFirstNodeOrdering

public QueryPlanNode[] getBreadthFirstNodeOrdering()

mxToString

public String mxToString()

getNode

public QueryPlanNode getNode(CompositeMetadata md)

Returns the query plan node corresponding to the given composite metadata instance. This checks object identity to find the node containing the composite metadata

treeToString

public String treeToString()

treeToString

public StringBuilder treeToString(StringBuilder bld)

toString

public String toString()

Overrides:

toString in class Object