ai.grakn.graql.internal.reasoner.cache

Class Cache<Q extends ReasonerQueryImpl,T extends Iterable<Answer>>

java.lang.Object

ai.grakn.graql.internal.reasoner.cache.Cache<Q,T>

Type Parameters:

Q - the type of query that is being cached

T - the type of answer being cached

Direct Known Subclasses:

LazyQueryCache, QueryCache

public abstract class Cache<Q extends ReasonerQueryImpl,T extends Iterable<Answer>>
extends Object

Generic container class for storing performed query resolutions. A one-to-one mapping is ensured between queries and entries. On retrieval, a relevant entry is identified by means of a query alpha-equivalence check. Defines two basic operations: - GET(Query) - retrieve an entry corresponding to a provided query, if entry doesn't exist return db lookup result of the query. - RECORD(Query) - if the query entry exists, update the entry, otherwise create a new entry. In each case return an up-to-date entry.

Author:

Kasper Piskorski

Method Summary

Modifier and Type	Method and Description
void	add(Cache<Q,T> c2) Perform cache union
void	clear() Clear the cache
boolean	contains(Q query) Query cache containment check
Collection<ai.grakn.graql.internal.reasoner.cache.CacheEntry<Q,T>>	entries()
abstract T	getAnswers(Q query) retrieve (possibly) cached answers for provided query
abstract java.util.stream.Stream<Answer>	getAnswerStream(Q query)
abstract Pair<java.util.stream.Stream<Answer>,MultiUnifier>	getAnswerStreamWithUnifier(Q query)
abstract Pair<T,MultiUnifier>	getAnswersWithUnifier(Q query)
Map<Pair<Var,Concept>,Set<Answer>>	getInverseAnswerMap(Q query) returns an inverse answer map with all query variables
Map<Pair<Var,Concept>,Set<Answer>>	getInverseAnswerMap(Q query, Set<Var> vars) return an inverse answer map which is more suitable for operations involving concept comparison (joins, filtering, etc.) NB: consumes the underlying stream for the specified query
Set<Q>	getQueries()
abstract java.util.stream.Stream<Answer>	record(Q query, java.util.stream.Stream<Answer> answers) record answer stream for a specific query and retrieve the updated stream
abstract T	record(Q query, T answers) record answer iterable for a specific query and retrieve the updated answers
void	remove(Cache<Q,T> c2) Perform cache difference
abstract void	remove(Cache<Q,T> c2, Set<Q> queries) cache subtraction of specified queries

Methods inherited from class java.lang.Object

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

Method Detail

add

public void add(Cache<Q,T> c2)

Perform cache union

Parameters:

c2 - union right operand

contains

public boolean contains(Q query)

Query cache containment check

Parameters:

query - to be checked for containment

Returns:

true if cache contains the query

getQueries

public Set<Q> getQueries()

Returns:

all queries constituting this cache

entries

public Collection<ai.grakn.graql.internal.reasoner.cache.CacheEntry<Q,T>> entries()

Returns:

all (query) -> (answers) mappings

remove

public void remove(Cache<Q,T> c2)

Perform cache difference

Parameters:

c2 - cache which mappings should be removed from this cache

clear

public void clear()

Clear the cache

record

public abstract T record(Q query,
                         T answers)

record answer iterable for a specific query and retrieve the updated answers

Parameters:

query - to be recorded

answers - to this query

Returns:

updated answer iterable

record

public abstract java.util.stream.Stream<Answer> record(Q query,
                                                       java.util.stream.Stream<Answer> answers)

record answer stream for a specific query and retrieve the updated stream

Parameters:

query - to be recorded

answers - answer stream of the query

Returns:

updated answer stream

getAnswers

public abstract T getAnswers(Q query)

retrieve (possibly) cached answers for provided query

Parameters:

query - for which to retrieve answers

Returns:

unified cached answers

getAnswersWithUnifier

public abstract Pair<T,MultiUnifier> getAnswersWithUnifier(Q query)

getAnswerStream

public abstract java.util.stream.Stream<Answer> getAnswerStream(Q query)

getAnswerStreamWithUnifier

public abstract Pair<java.util.stream.Stream<Answer>,MultiUnifier> getAnswerStreamWithUnifier(Q query)

getInverseAnswerMap

public Map<Pair<Var,Concept>,Set<Answer>> getInverseAnswerMap(Q query,
                                                              Set<Var> vars)

return an inverse answer map which is more suitable for operations involving concept comparison (joins, filtering, etc.) NB: consumes the underlying stream for the specified query

Parameters:

query - for answer are to be retrieved

vars - variable names of interest

Returns:

inverse answer map for specified query

getInverseAnswerMap

public Map<Pair<Var,Concept>,Set<Answer>> getInverseAnswerMap(Q query)

returns an inverse answer map with all query variables

Parameters:

query - for answer are to be retrieved

Returns:

inverse answer map for specified query

remove

public abstract void remove(Cache<Q,T> c2,
                            Set<Q> queries)

cache subtraction of specified queries

Parameters:

c2 - subtraction right operand

queries - to which answers shall be subtracted