Package com.googlecode.cqengine.index.support

Class IndexSupport

java.lang.Object

com.googlecode.cqengine.index.support.IndexSupport

public class IndexSupport
extends Object

Index utilities

Author:

Silvano Riz

Method Summary

Modifier and Type	Method	Description
static <O,A> ResultSet<O>	deduplicateIfNecessary(Iterable<? extends ResultSet<O>> results, Query<O> query, Attribute<O,A> attribute, QueryOptions queryOptions, int retrievalCost)	If a query option specifying logical deduplication was supplied, wrap the given result sets in ResultSetUnion, otherwise wrap in ResultSetUnionAll.

Methods inherited from class java.lang.Object

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

Method Detail

deduplicateIfNecessary

public static <O,A> ResultSet<O> deduplicateIfNecessary(Iterable<? extends ResultSet<O>> results,
                                                              Query<O> query,
                                                              Attribute<O,A> attribute,
                                                              QueryOptions queryOptions,
                                                              int retrievalCost)

If a query option specifying logical deduplication was supplied, wrap the given result sets in ResultSetUnion, otherwise wrap in ResultSetUnionAll.

There are two exceptions where a ResultSetUnionAll is used regardless of the logical deduplication query option:

• If the index is built on a SimpleAttribute which means that the same object could not exist in more than one StoredResultSet.
• If the query is an In query and it is marked as disjoint ( In.isDisjoint() returns true )

Parameters:

results - Provides the result sets to union

query - The query for which the union is being constructed

queryOptions - Specifies whether or not logical deduplication is required

retrievalCost - The resultSet retrieval cost

Returns:

A union view over the given result sets