Package com.googlecode.cqengine.index.support

Interface KeyStatisticsIndex<A,O>

All Superinterfaces:

Index<O>, ModificationListener<O>

All Known Subinterfaces:

KeyStatisticsAttributeIndex<A,O>, SortedKeyStatisticsAttributeIndex<A,O>, SortedKeyStatisticsIndex<A,O>

All Known Implementing Classes:

CompoundIndex, DiskIndex, HashIndex, NavigableIndex, OffHeapIndex, PartialDiskIndex, PartialNavigableIndex, PartialOffHeapIndex, PartialSortedKeyStatisticsAttributeIndex, PartialSQLiteIndex, SimplifiedSQLiteIndex, SQLiteDiskIdentityIndex, SQLiteIdentityIndex, SQLiteIndex, SQLiteOffHeapIdentityIndex

public interface KeyStatisticsIndex<A,O>
extends Index<O>

An index which allows the set of distinct keys to be queried, and which can return statistics on the number of objects stored in the buckets for each key.

Note that this interface reads statistics about keys and NOT about attribute values from the index. Often those statistics will be the same, however if a Quantizer is configured for an index, then often objects for several attribute values may have the same key and may be stored in the same bucket. Created by niall.gallagher on 09/01/2015.

Method Summary

Modifier and Type	Method	Description
Integer	getCountForKey(A key, QueryOptions queryOptions)
Integer	getCountOfDistinctKeys(QueryOptions queryOptions)	Returns the count of distinct keys in the index.
CloseableIterable<A>	getDistinctKeys(QueryOptions queryOptions)
CloseableIterable<KeyValue<A,O>>	getKeysAndValues(QueryOptions queryOptions)	Returns the keys and corresponding values for those keys in the index.
CloseableIterable<KeyStatistics<A>>	getStatisticsForDistinctKeys(QueryOptions queryOptions)	Returns the statistics KeyStatistics for all distinct keys in the index

Methods inherited from interface com.googlecode.cqengine.index.Index

getEffectiveIndex, isMutable, isQuantized, retrieve, supportsQuery

Methods inherited from interface com.googlecode.cqengine.engine.ModificationListener

addAll, clear, destroy, init, removeAll

Method Detail

getDistinctKeys

CloseableIterable<A> getDistinctKeys(QueryOptions queryOptions)

Parameters:

queryOptions - Optional parameters for the query

Returns:

The distinct keys in the index

getCountForKey

Integer getCountForKey(A key,
                       QueryOptions queryOptions)

Parameters:

key - A key which may be contained in the index

queryOptions - Optional parameters for the query

Returns:

The number of objects stored in the bucket in the index with the given key

getCountOfDistinctKeys

Integer getCountOfDistinctKeys(QueryOptions queryOptions)

Returns the count of distinct keys in the index.

Parameters:

queryOptions - Optional parameters for the query

Returns:

The count of distinct keys in the index.

getStatisticsForDistinctKeys

CloseableIterable<KeyStatistics<A>> getStatisticsForDistinctKeys(QueryOptions queryOptions)

Returns the statistics KeyStatistics for all distinct keys in the index

Parameters:

queryOptions - Optional parameters for the query

Returns:

The statistics KeyStatistics for all distinct keys in the index

getKeysAndValues

CloseableIterable<KeyValue<A,O>> getKeysAndValues(QueryOptions queryOptions)

Returns the keys and corresponding values for those keys in the index. Note the same key will be returned multiple times if more than one object has the same key. Also the same value might be returned multiple times, each time for a different key, if the index is built on a multi-value attribute.

Parameters:

queryOptions - Optional parameters for the query

Returns:

The keys and corresponding values for those keys in the index