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From Maros Ivanco <maros_iva...@datalan.sk>
Subject RE: lucene API
Date Thu, 18 Aug 2005 16:40:16 GMT

-----"Robert Engels" <rengels@ix.netcom.com> wrote: -----

>To: <java-dev@lucene.apache.org>
>From: "Robert Engels" <rengels@ix.netcom.com>
>Date: 17.08.2005 16:20
>Subject: RE: lucene API
>
>I think you should leave the API as is, and write a custom XML writer
>for
>lucene search results. The request is trivial since you can simple
>pass the
>single string.

Well, actually that is not true. You assume that all I need to do is the
search. But I also need to expose index reading and index writing API. I
need
reading API to remove expired documents, index management, end so forth. I
need writing API to write documents by robot which resides on different
machine. Anyway, even exposing only the search API is not trivial in the
case
you want to search in multiple languages (you have to use custom
analyzers),
specify order, or filter. Even if you would not, there is always Hits
object,
which is (by its nature) nonserializable.

>I would not write wrapper beans just to use the
>built-in
>serialization support.
>
>The custom XML writer will be MUCH, MUCH faster, as you do not need
>to create an XML document first.

Perhaps faster to run (I must admit you have a point here), but defenetly
not
faster to develop. Usage of the custom de/serializers is also discouraged
by
jax-rpc spec (which is not an issue), and is not well documented.
Anyway, it is imposible to write de/serializers for certain Lucene classes.
For instance, you cannot write de/serializers for
org.apache.lucene.search.Filter and its subclasses,
because the inner state of their instances is not accessible. Other
examples
of nonserializable classes include Hits, Sort, SortField, ScoreDoc,
TopDocs,
...

So, to summarize, I do not see Lucene API ready for integration with other
systems, even though it may be very effective when used standalone.

Maros.

>The XML needed to support a Lucene
>search
>result is quite trivial.
>
>R
>
>-----Original Message-----
>From: Maros Ivanco [mailto:maros_ivanco@datalan.sk]
>Sent: Wednesday, August 17, 2005 8:27 AM
>To: java-dev@lucene.apache.org
>Cc: Marek Baumerth
>Subject: lucene API
>
>
>
>
>Hi there,
>
>   I am creating a search solution based on Lucene. A part of the
>solution
>   is Lucene web service. Even though the Lucene API is very
>straitforward
>   to use on a local machine, I found creation of Lucene WS to be
>extremely
>   difficult. The problem causes the API, which very often does not
>obey
>   even trivial coding conventions (getter and setter names, for
>instance).
>   As a result, the jax-rpc subsystem is unable to produce correct
>   serializers and deserializers. From my point of view, there are
>serveral
>   possibilities to solve the problem:
>
> 1., write envelopes for nonserializable objects (Document, Field,
>Term,
> ...)
> 2., write custom serializers and deserializers
> 3., change lucene API
>
>1. requires creation of many envelopes, since most of the Lucene
>classes do
>not obey JavaBean semantics thus, they are not serializable by
>jax-rpc.
>Wrapping and uwrapping of Lucene objects takes extra processing.
>Moreover,
>the un/wrapping is sometimes not possible, because some objects
>(Filters,
>for instance) do not exhibit their full state. I am doing this right
>now
>(and doing, and doing,... I cannot see the end :-)).
>
>2. requires creation of de/serializer for every nonserializable
>class. Also
>requires extra configuration + generation of factories. Twice as
>difficult
>as solution 1. Moreover, this solution renders resulting WS as
>nonportable.
>
>3. requires change of lucene API in the way that will allow either
>direct
>de/serialization or, at least, the solution 1. As far as Lucene is
>open
>sourced, everybody can make changes, but the real question is,
>whether the
>changes will become part of the official distribution. If not, the
>overall
>search solution will remain stucked with current release.
>
>I would personally prefer the third one, but only if the changes will
>make
>it to the official release. Our company plans to deploy several
>instances
>of the solution. There is certain probability, that my employer will
>contribute some resources (my time) to the project. The question is,
>whether the contemporary development comunity is willing to accept
>this
>kind of changes and if I can participate. So, is it?
>
>Maros.
>
>
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