Returns the a BitSet representing the Boolean composition
of the filters that have been added.
//create a new bitSet
BitSet returnBits = null;
//SHOULD filters
if (shouldFilters!=null)
{
returnBits = ((Filter)shouldFilters.get(0)).bits(reader);
// avoid changing the original bitset - it may be cached
returnBits=(BitSet) returnBits.clone();
if (shouldFilters.size() > 1)
{
for (int i = 1; i < shouldFilters.size(); i++)
{
returnBits.or(((Filter)shouldFilters.get(i)).bits(reader));
}
}
}
//NOT filters
if (notFilters!=null)
{
for (int i = 0; i < notFilters.size(); i++)
{
BitSet notBits=((Filter)notFilters.get(i)).bits(reader);
if(returnBits==null)
{
returnBits=(BitSet) notBits.clone();
returnBits.flip(0,reader.maxDoc());
}
else
{
returnBits.andNot(notBits);
}
}
}
//MUST filters
if (mustFilters!=null)
{
for (int i = 0; i < mustFilters.size(); i++)
{
BitSet mustBits=((Filter)mustFilters.get(i)).bits(reader);
if(returnBits==null)
{
if(mustFilters.size()==1)
{
returnBits=mustBits;
}
else
{
//don't mangle the bitset
returnBits=(BitSet) mustBits.clone();
}
}
else
{
returnBits.and(mustBits);
}
}
}
if(returnBits==null)
{
returnBits=new BitSet(reader.maxDoc());
}
return returnBits;
