Re: MultiFieldQueryParser default operator

[Michael Giles]

This would be great to get fixed (I think I emailed a similar question a 
month or so ago).  If MultiFieldQueryParser is being mucked with, the 
constructor should be updated to take an array of fields instead of the 
single field it takes currently.  The code snippet below is actually 
passing the query ("britney spears") into the constructor instead of a 
default field.  If you made that single change to the constructor, no other 
changes would be necessary, as you could simply call the parse(String) 
method from QueryParser to do your work.

-Mike

At 10:03 AM 10/30/2003, you wrote:
It was posted on lucene-dev, not lucene-user.  I've pasted it below.

I will be fixing this at some point in the near future based on this fix 
and other related ones needed.

        Erik

-----

From: Bernhard Messer <[EMAIL PROTECTED]>
Date: Wed Oct 29, 2003  11:27:02  AM US/Eastern
To: Lucene Developers List <[EMAIL PROTECTED]>
Subject: MultiFieldQueryParser, can't change default search operator
Reply-To: "Lucene Developers List" <[EMAIL PROTECTED]>
hi all,

just played around with the MultiFieldQueryParser and didn't find a 
working way to change the "operator" value.

The problem is that MultiFieldQueryParser is implementing two public 
static methods "parse" only. Calling one of those, in the extended 
superclass, the static method implementation for "parse" is called. Due to 
the fact that the QueryParser class creates a new Instance for each call 
thru the static method, the "operator" flag is simply ignored.

There would be a simple fix within MultiFieldQueryParser class without 
touching the rest of the system. One have to add a new non static method 
"parse" which could look like this:

/***********************************************************/
public Query parse(String query, String[] fields) throws ParseException {
       BooleanQuery bQuery = new BooleanQuery();
       for (int i = 0; i < fields.length; i++)
       {
           QueryParser parser = new QueryParser(fields[i], analyzer);
           parser.setOperator(getOperator());
           Query q = parser.parse(query);
           bQuery.add(q, false, false);
       }
       return bQuery;
     }
/***********************************************************/
To test the new implementation, following code fragment can be used:

/***********************************************************/
           Directory directory = 
FSDirectory.getDirectory("/tmp/idx-test", false);
           Analyzer analyzer = new SimpleAnalyzer();
           Searcher searcher = new IndexSearcher(directory);
           Hits hits = null;
                     String[] fields = { "contents", "title" };
           MultiFieldQueryParser parser = new 
MultiFieldQueryParser("britney spears", analyzer);

parser.setOperator(QueryParser.DEFAULT_OPERATOR_AND);
                             Query query = parser.parse("britney spears", 
fields);
                     System.out.println("Query: " + query.toString());
                     hits = searcher.search(query);

           System.out.println ("Results: " + hits.length());
                     searcher.close();
/***********************************************************/
best regards

Bernhard


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