Package com.atlassian.greenhopper.service.lucene

Class LeftJoin

java.lang.Object

com.atlassian.greenhopper.service.lucene.LeftJoin

public class LeftJoin
extends Object

A query that performs a join between two indexes (left and right). This query can be used on the left index, and it selects documents in the left that match documents on the right. Documents on the left/right are "matched" using a fields with common values.

Specifically, this query will match documents in leftIndex, where leftdoc.leftField == rightdoc.rightField, and rightdoc is in rightDocIds;

This implementation doesn't do anything smart wrt to scoring at the moment.

Performance will be expected to be O(l+r); l is the number of Terms that match on the left, r is the number of terms that match on the right.

In the case where there is a 1-1 between left and right, best-case becomes O(1)

Author:

Matt Quail

Constructor Summary

Constructors

Constructor	Description
LeftJoin(String leftField, RightJoinEnum rightEnum)

Method Summary

Modifier and Type	Method	Description
BitSet	computeResult(org.apache.lucene.index.IndexReader leftReader)

Methods inherited from class java.lang.Object

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

Constructor Details

LeftJoin

public LeftJoin(String leftField,
 RightJoinEnum rightEnum)

Parameters:

leftField - the match field on the left

Method Details

computeResult

public BitSet computeResult(org.apache.lucene.index.IndexReader leftReader)
                     throws IOException

Throws:

IOException