How do you run Lucene on .net?

Question

Lucene is an excellent search engine, but the .NET version is behind the official Java release (latest stable .NET release is 2.0, but the latest Java Lucene version is 2.4,

Answer 1

Download the source and build it. I did this just last weekend and it was easy. No problem at all. The source is at version 2.3.1.

I'm subscribed to the mailing list and judging from it, Lucene.Net is being developed actively.

Answer 2

One way I found, which was surprised could work: Create a .NET DLL from a Java .jar file! Using IKVM you can download Lucene, get the .jar file, and run:

ikvmc -target:library <path-to-lucene.jar>

which generates a .NET dll like this: lucene-core-2.4.0.dll

You can then just reference this DLL from your project and you're good to go! There are some java types you will need, so also reference IKVM.OpenJDK.ClassLibrary.dll. Your code might look a bit like this:

QueryParser parser = new QueryParser("field1", analyzer);
java.util.Map boosts = new java.util.HashMap();
boosts.put("field1", new java.lang.Float(1.0));
boosts.put("field2", new java.lang.Float(10.0));

MultiFieldQueryParser multiParser = new MultiFieldQueryParser
                      (new string[] { "field1", "field2" }, analyzer, boosts);
multiParser.setDefaultOperator(QueryParser.Operator.OR);

Query query = multiParser.parse("ABC");
Hits hits = isearcher.search(query);

I never knew you could have Java to .NET interoperability so easily. The best part is that C# and Java is "almost" source code compatible (where Lucene examples are concerned). Just replace System.Out with Console.Writeln :).

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Update: When building libraries like the Lucene highlighter, make sure you reference the core assembly (else you'll get warnings about missing classes). So the highlighter is built like this:

ikvmc -target:library lucene-highlighter-2.4.0.jar -r:lucene-core-2.4.0.dll

Answer 3

I converted the Lucene 2.4 from jar to dll through this way but now it gives me an error that 'Type or namespace Lucene could not be found'. I removed the old dll from the project and added reference for the new one. I really want to get rid of the old version as it took around 2 days and in the end during optimization it gave some error and now the index is not updateable :S. I read somewhere that Lucene 2.4 indexing speed is many times faster than the old versions, if I use 2.3.1 from SVN will that be faster too?

Answer 4

Lucene.net is under development and now has three committers