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From Shad Storhaug <s...@shadstorhaug.com>
Subject RE: Possible Issue with DoubleField
Date Fri, 11 Aug 2017 04:58:02 GMT
Hi Alexander,

Thanks for the report.

To answer your second question, Lucene's design has changed to accommodate a "LazyField" (in
the Lucene.Net.Misc package) that is readonly. The return type of Document.GetField(string)
is IIndexableField, not Field and therefore typically requires a cast in Java in order to
use. To make this easier to work with in .NET, I have added a generic extension method overload
so the cast is more obvious.

var field = doc.GetField<Field>(fieldName);

I am trying to avoid using something like public Field GetFieldAsField(), which would result
in an exception in the rare case the underlying IIndexableField type could not be cast to
a Field type, and it would not be so obvious that you have to call GetField(string) and cast
to an alternative type.

You can try this approach out by copying the extension method into your project. https://github.com/apache/lucenenet/blob/master/src/Lucene.Net/Support/Document/DocumentExtensions.cs.



For the Single/Double field issue, thanks for putting together the code sample. It is a bit
unclear from your question though - was this something that worked in 4.8.0.770-beta that
quit working in 4.8.0-beta00004?


Thanks,
Shad Storhaug (NightOwl888)


-----Original Message-----
From: Roethinger, Alexander [mailto:aroethinger@affili.net] 
Sent: Friday, August 11, 2017 5:32 AM
To: dev@lucenenet.apache.org
Subject: Possible Issue with DoubleField

Dear Devs,

I just updated my search application from v4.8.0.770-beta to v4.8.0-beta00004.
It required some plausible code adjustments but otherwise worked just fine with all of my
unit tests now passing.

I did notice something though with DoubleField (and possibly with SingleField as well, Int32Field
and Int64Field both work fine) after extending my unit tests for some edge cases using  the
MaxValues for those types.
Maybe I'm just missing something, but I thought I would raise it to the community and would
appreciate your thoughts:

a) When storing a DoubleField with a value of double.MaxValue, the string representation of
the field value is incorrect. Could it be that the Round-Trip Format Specifier "R" is missing?
b) When retrieving the same field, the FieldType properties of the retrieved field are not
the same as when the field was stored.

This results in two challenges:
1) I can't use the Document.Get() method to retrieve the precise value. Instead I have to
use GetNumericValue().
2) When examining the values of FieldType for the retrieved field, the properties do not match
those of the stored field, ie. NumericType is set to NONE even though it should be DOUBLE
or the value of IsTokenized is changed.
I'm not sure if this is expected behavior or not. I would have assumed that FieldType retrieves
the values according to the way the field was originally created.
The problem with these two points is that I can't easily deduct how to properly retrieve the
value based on the value of NumericType just  from reading the field.

Another point that confuses me:
Why do I need to explicitly cast FieldType to access the NumericType property instead of just
 accessing the FieldType property of the Field? (see line 34: var fieldType = (FieldType)field.FieldType;)

The sample ConsoleApplication code below illustrates the behavior.

Any feedback is welcome!
And thanks for all the great work you have been doing!

Kind regards
Alexander

CODE:

using Lucene.Net.Analysis;
using Lucene.Net.Analysis.Standard;
using Lucene.Net.Documents;
using Lucene.Net.Index;
using Lucene.Net.Search;
using Lucene.Net.Store;
using Lucene.Net.Util;
using System;

namespace LuceneTest
{
    class Program
    {
        static void Main(string[] args)
        {
            Directory dir = new RAMDirectory();
            Analyzer analyzer = new StandardAnalyzer(LuceneVersion.LUCENE_48);
            IndexWriterConfig iwc = new IndexWriterConfig(LuceneVersion.LUCENE_48, analyzer);

            double value = double.MaxValue;
            string fieldName = "DoubleField";

            FieldType type = new FieldType();
            type.IsIndexed = true;
            type.IsStored = true;
            type.IsTokenized = false;
            type.NumericType = NumericType.DOUBLE;


            using (IndexWriter writer = new IndexWriter(dir, iwc))
            {
                Document doc = new Document();
                var field = new DoubleField(fieldName, value, type);
                var fieldType = (FieldType)field.FieldType;

                Console.WriteLine("DoubleField values for indexed value");
                Console.WriteLine("StringValue: {0}", field.GetStringValue());
                Console.WriteLine("NumericValue: {0:R}", field.GetNumericValue());
                Console.WriteLine("IsIndexed: {0}", fieldType.IsIndexed);
                Console.WriteLine("IsStored: {0}", fieldType.IsStored);
                Console.WriteLine("IsTokenized: {0}", fieldType.IsTokenized);
                Console.WriteLine("Numreric: {0}", fieldType.NumericType);

                doc.Add(field);
                writer.AddDocument(doc);
                writer.Commit();
            }

            Console.WriteLine();

            using (IndexReader reader = DirectoryReader.Open(dir))
            {
                IndexSearcher searcher = new IndexSearcher(reader);
                var hits = searcher.Search(new MatchAllDocsQuery(), 10).ScoreDocs;

                Document doc = searcher.Doc(hits[0].Doc);
                var field = doc.GetField(fieldName);
                var fieldType = (FieldType)field.FieldType;

                Console.WriteLine("DoubleField values for searched value");
                Console.WriteLine("StringValue: {0}", field.GetStringValue());
                Console.WriteLine("NumericValue: {0:R}", field.GetNumericValue());
                Console.WriteLine("IsIndexed: {0}", fieldType.IsIndexed);
                Console.WriteLine("IsStored: {0}", fieldType.IsStored);
                Console.WriteLine("IsTokenized: {0}", fieldType.IsTokenized);
                Console.WriteLine("Numreric: {0}", fieldType.NumericType);

            }

            Console.ReadKey();

            dir.Dispose();
        }

    }
}










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