package org.apache.lucene.xmlparser.builders;
import org.apache.lucene.search.BoostingQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.xmlparser.DOMUtils;
import org.apache.lucene.xmlparser.ParserException;
import org.apache.lucene.xmlparser.QueryBuilder;
import org.w3c.dom.Element;
public class BoostingQueryBuilder implements QueryBuilder
{
private QueryBuilder factory;
float defaultBoost=0.01f;
public BoostingQueryBuilder (QueryBuilder factory)
{
this.factory=factory;
}
public Query getQuery(Element e) throws ParserException
{
Element mainQueryElem=DOMUtils.getChildByTagName(e,"Query");
if(mainQueryElem==null)
{
throw new ParserException("BoostingQuery missing a \"Query\" child element");
}
mainQueryElem=DOMUtils.getFirstChildElement(mainQueryElem);
if(mainQueryElem==null)
{
throw new ParserException("BoostingQuery \"Query\" element missing a child element");
}
Query mainQuery=factory.getQuery(mainQueryElem);
Element boostQueryElem=DOMUtils.getChildByTagName(e,"BoostQuery");
float boost=DOMUtils.getAttribute(boostQueryElem,"boost",defaultBoost);
if(boostQueryElem==null)
{
throw new ParserException("BoostingQuery missing a \"BoostQuery\" child element");
}
boostQueryElem=DOMUtils.getFirstChildElement(boostQueryElem);
if(boostQueryElem==null)
{
throw new ParserException("BoostingQuery \"BoostQuery\" element missing a child element");
}
Query boostQuery=factory.getQuery(boostQueryElem);
BoostingQuery bq = new BoostingQuery(mainQuery,boostQuery,boost);
bq.setBoost(DOMUtils.getAttribute(e,"boost",1.0f));
return bq;
}
}