com.apple.foundationdb.record.provider.foundationdb

Class IndexAggregateGroupKeys

java.lang.Object

com.apple.foundationdb.record.provider.foundationdb.IndexAggregateGroupKeys

Direct Known Subclasses:

IndexAggregateGroupKeys.Conditions, IndexAggregateGroupKeys.IndexScan

@API(value=EXPERIMENTAL)
public abstract class IndexAggregateGroupKeys
extends Object

Helper class for extracting grouping keys from an IndexAggregateFunction given query conditions. To implement an aggregate function XXX(value BY group) using an index, the group needs to be fixed, which will be true when the query has a filter on group (equivalent to SQL WHERE group = ?).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	IndexAggregateGroupKeys.Conditions
protected static class	IndexAggregateGroupKeys.IndexScan

Constructor Summary

Constructors

Constructor and Description
IndexAggregateGroupKeys()

Method Summary

Modifier and Type	Method and Description
static Optional<IndexAggregateGroupKeys>	conditionsToGroupKeys(IndexAggregateFunction function, QueryComponent conditions)
static Optional<IndexAggregateGroupKeys>	conditionsToGroupKeys(KeyExpression operand, QueryComponent conditions)
abstract int	getColumnSize() Get the size of the prefix of the index aggregate that is returned.
abstract Key.Evaluated	getGroupKeys(FDBRecordStoreBase<?> store, EvaluationContext context) Get the grouping key (GROUP BY) for the index aggregate from the given context.
static IndexAggregateGroupKeys	indexScanToGroupKeys(String recordKey, int prefixSize)

Methods inherited from class java.lang.Object

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

Constructor Detail

IndexAggregateGroupKeys

public IndexAggregateGroupKeys()

Method Detail

getGroupKeys

@Nonnull
public abstract Key.Evaluated getGroupKeys(@Nullable
                                                    FDBRecordStoreBase<?> store,
                                                    @Nullable
                                                    EvaluationContext context)

Get the grouping key (GROUP BY) for the index aggregate from the given context.

Parameters:

store - the record store for the query

context - context in which to evaluate keys

Returns:

the grouping key

getColumnSize

public abstract int getColumnSize()

Get the size of the prefix of the index aggregate that is returned. That is, the size of {#link #getGroupKeys}.

Returns:

number of items in the grouping key

conditionsToGroupKeys

public static Optional<IndexAggregateGroupKeys> conditionsToGroupKeys(@Nonnull
                                                                      IndexAggregateFunction function,
                                                                      @Nullable
                                                                      QueryComponent conditions)

conditionsToGroupKeys

public static Optional<IndexAggregateGroupKeys> conditionsToGroupKeys(@Nonnull
                                                                      KeyExpression operand,
                                                                      @Nullable
                                                                      QueryComponent conditions)

indexScanToGroupKeys

public static IndexAggregateGroupKeys indexScanToGroupKeys(@Nonnull
                                                           String recordKey,
                                                           int prefixSize)