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From Sandeep Khanzode <>
Subject Re: Determine whether a MatchAllQuery or a Query with atleast one Term
Date Mon, 30 Nov 2015 05:15:34 GMT
Hi Uwe,
Actually, I do use that logic in another part of the code for some other functionality :).
However, I was wondering if we have some direct API to check for the presence of terms (Terms,
NumericRanges, etc.) given an abstract query. My requirement is simple: Irrespective of the
Query sub-class implementation (which will either extend or change in the future), I want
to check whether the net effect of this query (bool or otherwise) is a MatchAllQuery (i.e.
without any terms) or a query with at least one term, or numeric range.
The alternative to traverse the bool hierarchy and check instanceOf() on every clause for
a Query Subclass may be involved, cumbersome, and prone to error. Your thoughts? -----------------------Thanks
n Regards,
Sandeep Ramesh Khanzode 

    On Saturday, November 28, 2015 5:29 PM, Uwe Schindler <> wrote:


You can also traverse a BooleanQuery. Just do instanceof BooleanQuery checks and if it is
a BooleanQuery recursively iterate over all clauses [you can use a BooleanQuery in a for-each
java loop as it implements Iterable]. For each clause recurse and check types again. Then
you should be able to detect all types of queries in the tree.


Uwe Schindler
H.-H.-Meier-Allee 63, D-28213 Bremen

> -----Original Message-----
> From: Sandeep Khanzode []
> Sent: Saturday, November 28, 2015 12:22 PM
> To:
> Subject: Re: Determine whether a MatchAllQuery or a Query with atleast
> one Term
> Hi,
> Actually, the MatchAllQuery, for all I know (since it is invoked by the client)
> can be wrapped in a Bool Query type. Hence, it is difficult for me to traverse
> the Bool Query clauses and determine MatchAll, whereas there may be
> other clauses which do contain a TermQuery or a NumericRangeQuery in
> which case a MatchAllQuery check is futile.
> Given any query, Bool Query or MatchAll, or a specific subclass of Query,
> what would be the safe way to determine that this is not a MatchAll query
> without any terms, or whether this is a query that contains at least one term
> or range? -----------------------Thanks n Regards,
> Sandeep Ramesh Khanzode
>    On Saturday, November 28, 2015 12:30 PM, Michael Wilkowski
> <> wrote:
>  Instanceof?
> MW
> Sent from Mi phone
> On 28 Nov 2015 06:57, "Sandeep Khanzode"
> <>
> wrote:
> > Hi,
> > I have a question.
> > In my program, I need to check whether the input query is a MatchAll
> Query
> > that contains no terms, or a Query (any variant) that has at least one
> > term. For typical Term queries, this seems reasonable to be done with
> > Query.extractTerms(Set<> terms) which gives the list of terms.
> > However, when there is a NumericRangeQuery, this method throws an
> > UnsupportedOperationException.
> > How can I determine that a NumericRangeQuery or any non-Term query
> exists
> > in the Input Query and differentiate it from the MatchAllQuery? -- SRK

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