Hi, Niels.
Mattias just responded yesterday to me on a similar question. See below:
Rick
======
Hi Rick,
you could probably get the keys from the IndexReader, like so:
// I'm in LuceneIndex now
public Iterable<String> getKeys()
{
IndexSearcherRef searcher = service.dataSource().getIndexSearcher(
identifier, true );
try
{
IndexReader reader = searcher.getSearcher().getIndexReader();
Collection<String> fieldNames = reader.getFieldNames(
FieldOption.ALL );
// Make a copy since we don't know if the result is final or not
Collection<String> result = new ArrayList<String>( fieldNames );
result.remove( KEY_DOC_ID );
result.remove( KEY_START_NODE_ID );
result.remove( KEY_END_NODE_ID );
return result;
}
finally
{
searcher.closeStrict();
}
}
This is a perhaps bit crude implementation and will only work on committed
stuff, not any transactional state. This is a start at least.
public Iterable<String> getValues( String key )
{
IndexSearcherRef searcher = service.dataSource().getIndexSearcher(
identifier, true );
try
{
IndexReader reader = searcher.getSearcher().getIndexReader();
Collection<String> result = new ArrayList<String>();
TermEnum terms = reader.terms( new Term( key ) );
do
{
result.add( terms.term().text() );
}
while ( terms.next() );
return result;
}
catch ( IOException e )
{
throw new RuntimeException( e );
}
finally
{
searcher.closeStrict();
}
}
Suffers from the same problem of transactional state and also doesn't consider
that values could be other types, f.ex. integers where the string is a weird
encoding of such a value.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Niels Hoogeveen
Sent: Friday, June 17, 2011 8:30 AM
To: [email protected]
Subject: [Neo4j] all values of a key-object pair
I have run into the situation where I want to add key value pairs to the Lucene
index, where I have no need to store the value in a property, but I would like
to know which values are stored in the Lucene index for a given key-object
pair. Use case: Loading Dbpedia in Neo4J, I load all entities and all
redirects. Every entity has a unique URL, as does every redirect. URL's are
stored in Lucene to look up the node that corresponds to an entity. I have no
need to store redirects, neither as node nor as a String array property (one
entity can have more than one redirect), instead I want to store the redirect
URL in the Lucene index, pointing to the associated entity node. In certain
cases, however, I would like to know the redirect URL's associated with a
certain entity. So I would like to be able to retrieve the values stored in the
Lucene index for a given key-object pair. Is this possible? If not with the
current setup, would it be possible to add such functionality? Kind re
gards,Niels Hoogeveen
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