org.janusgraph.graphdb.query

Class QueryUtil

java.lang.Object

org.janusgraph.graphdb.query.QueryUtil

public class QueryUtil
extends Object

Utility methods used in query optimization and processing.

Author:

Matthias Broecheler ([email protected])

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	QueryUtil.IndexCall<R>

Constructor Summary

Constructors

Constructor and Description
QueryUtil()

Method Summary

Modifier and Type	Method and Description
static int	adjustLimitForTxModifications(StandardJanusGraphTx tx, int uncoveredAndConditions, int limit)
static <E extends JanusGraphElement> And<E>	constraints2QNF(StandardJanusGraphTx tx, List<PredicateCondition<String,E>> constraints) Prepares the constraints from the query builder into a QNF compliant condition.
static int	convertLimit(long limit)
static Map.Entry<RelationType,Collection>	extractOrCondition(Or<JanusGraphRelation> condition)
static Iterable<JanusGraphEdge>	getEdges(StandardJanusGraphTx tx, PropertyKey key, Object equalityCondition)
static Iterable<JanusGraphEdge>	getEdges(StandardJanusGraphTx tx, String key, Object equalityCondition)
static InternalRelationType	getType(StandardJanusGraphTx tx, String typeName)
static Iterable<JanusGraphVertex>	getVertices(StandardJanusGraphTx tx, PropertyKey key, Object equalityCondition)
static Iterable<JanusGraphVertex>	getVertices(StandardJanusGraphTx tx, String key, Object equalityCondition)
static boolean	isEmpty(Condition<?> condition)
static boolean	isQueryNormalForm(Condition<?> condition) Query-normal-form (QNF) for JanusGraph is a variant of CNF (conjunctive normal form) with negation inlined where possible
static int	mergeHighLimits(int limit1, int limit2)
static int	mergeLowLimits(int limit1, int limit2)
static <R> List<R>	processIntersectingRetrievals(List<QueryUtil.IndexCall<R>> retrievals, int limit)
static <E extends JanusGraphElement> Condition<E>	simplifyQNF(Condition<E> condition)

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryUtil

public QueryUtil()

Method Detail

adjustLimitForTxModifications

public static int adjustLimitForTxModifications(StandardJanusGraphTx tx,
                                                int uncoveredAndConditions,
                                                int limit)

convertLimit

public static int convertLimit(long limit)

mergeLowLimits

public static int mergeLowLimits(int limit1,
                                 int limit2)

mergeHighLimits

public static int mergeHighLimits(int limit1,
                                  int limit2)

getType

public static InternalRelationType getType(StandardJanusGraphTx tx,
                                           String typeName)

getVertices

public static Iterable<JanusGraphVertex> getVertices(StandardJanusGraphTx tx,
                                                     PropertyKey key,
                                                     Object equalityCondition)

getVertices

public static Iterable<JanusGraphVertex> getVertices(StandardJanusGraphTx tx,
                                                     String key,
                                                     Object equalityCondition)

getEdges

public static Iterable<JanusGraphEdge> getEdges(StandardJanusGraphTx tx,
                                                PropertyKey key,
                                                Object equalityCondition)

getEdges

public static Iterable<JanusGraphEdge> getEdges(StandardJanusGraphTx tx,
                                                String key,
                                                Object equalityCondition)

isQueryNormalForm

public static boolean isQueryNormalForm(Condition<?> condition)

Query-normal-form (QNF) for JanusGraph is a variant of CNF (conjunctive normal form) with negation inlined where possible

Parameters:

condition -

Returns:

simplifyQNF

public static <E extends JanusGraphElement> Condition<E> simplifyQNF(Condition<E> condition)

isEmpty

public static boolean isEmpty(Condition<?> condition)

constraints2QNF

public static <E extends JanusGraphElement> And<E> constraints2QNF(StandardJanusGraphTx tx,
                                                                   List<PredicateCondition<String,E>> constraints)

Prepares the constraints from the query builder into a QNF compliant condition. If the condition is invalid or trivially false, it returns null.

Type Parameters:

E -

Parameters:

tx -

constraints -

Returns:

See Also:

isQueryNormalForm(org.janusgraph.graphdb.query.condition.Condition)

extractOrCondition

public static Map.Entry<RelationType,Collection> extractOrCondition(Or<JanusGraphRelation> condition)

processIntersectingRetrievals

public static <R> List<R> processIntersectingRetrievals(List<QueryUtil.IndexCall<R>> retrievals,
                                                        int limit)