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From: Ian Lea <ian.lea@gmail.com>
Date: Mon, 1 Feb 2010 09:19:53 +0000
Message-ID: <8c4e68611002010119k34299a9dgfc2d59b6301ac0a0@mail.gmail.com>
Subject: Re: best way to compare Documents
To: java-user@lucene.apache.org
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> ...
> Is there some convenient way to compare Lucene Documents?

Not that I know of.

> I want to check if I should update a document based on whether field values have changed and whether fields have been added or removed.
>
> Is it as simple as:
>
> newDoc.equals(oldDoc)

No!

> I don't need to create the newDoc first, so I could compare by field. I am creating Fields like so:
>
> new Field("modified", modified, Field.Store.YES, Field.Index.NOT_ANALYZED)
>
> So, would it be better to:
> * check oldDoc's fields count against the to be created documents desired fields count, and
> * loop through the fields and compare values

Yes.  Of course you won't be able to compare unstored fields.

> Is there a better way to create Fields and/or Documents for this type of thing?

Hash or CRC as Shashi suggested, but you'll still need compare old and
new hash values.


--
Ian.

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