org.hypergraphdb

Interface HGBidirectionalIndex<KeyType,ValueType>

All Superinterfaces:

HGIndex<KeyType,ValueType>, HGSearchable<KeyType,ValueType>

public interface HGBidirectionalIndex<KeyType,ValueType>
extends HGIndex<KeyType,ValueType>

A HGBidirectionalIndex provides efficient searching of an index entry by value as well as by key. It can be used as an efficient associative array between keys and values.

Author:

Borislav Iordanov

Method Summary

Methods

Modifier and Type	Method and Description
long	countKeys(ValueType value) Return the number of keys pointing to the given values.
HGRandomAccessResult<KeyType>	findByValue(ValueType value) Return a HGSearchResult over all keys whose value is the value parameter.
KeyType	findFirstByValue(ValueType value) Return a key whose value is the value parameter.

Methods inherited from interface org.hypergraphdb.HGIndex

addEntry, close, count, count, find, findFirst, getName, isOpen, open, removeAllEntries, removeEntry, scanKeys, scanValues

Method Detail

findByValue

HGRandomAccessResult<KeyType> findByValue(ValueType value)

Return a HGSearchResult over all keys whose value is the value parameter.

findFirstByValue

KeyType findFirstByValue(ValueType value)

Return a key whose value is the value parameter. If more than one index entry exists with that particular value, generally the one that was added first will be returned, but this is not guarantueed.

countKeys

long countKeys(ValueType value)

Return the number of keys pointing to the given values. This operation must execute in constant time, regardless of the data in the index.

Parameters:

value - The value.