com.thinkaurelius.titan.graphdb.query

Class QueryUtil

java.lang.Object

com.thinkaurelius.titan.graphdb.query.QueryUtil

public class QueryUtil
extends Object

Utility methods used in query optimization and processing.

Author:

Matthias Broecheler (me@matthiasb.com)

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

Methods

Modifier and Type	Method and Description
static int	adjustLimitForTxModifications(StandardTitanTx tx, int uncoveredAndConditions, int limit)
static <E extends TitanElement> And<E>	constraints2QNF(StandardTitanTx tx, List<PredicateCondition<String,E>> constraints) Prepares the constraints from the query builder into a QNF compliant condition.
static InternalRelationType	getType(StandardTitanTx tx, String typeName)
static boolean	isEmpty(Condition<?> condition)
static boolean	isQueryNormalForm(Condition<?> condition) Query-normal-form (QNF) for Titan is a variant of CNF (conjunctive normal form) with negation inlined where possible
static <R> List<R>	processIntersectingRetrievals(List<QueryUtil.IndexCall<R>> retrievals, int limit)
static <E extends TitanElement> 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(StandardTitanTx tx,
                                int uncoveredAndConditions,
                                int limit)

getType

public static InternalRelationType getType(StandardTitanTx tx,
                           String typeName)

isQueryNormalForm

public static boolean isQueryNormalForm(Condition<?> condition)

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

Parameters:

condition -

Returns:

simplifyQNF

public static final <E extends TitanElement> Condition<E> simplifyQNF(Condition<E> condition)

isEmpty

public static boolean isEmpty(Condition<?> condition)

constraints2QNF

public static <E extends TitanElement> And<E> constraints2QNF(StandardTitanTx 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(com.thinkaurelius.titan.graphdb.query.condition.Condition)

processIntersectingRetrievals

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