Queries have a syntax, with terms and operators. If no operators, there is
an implicit operator (AND/OR = mandatory/optional). Generally a sequence of
terms will always generate a BooleanQuery.
So, any time you use some lexical construct that has meaning to the query
parser that you don't want, then you need to escape it.
-- Jack Krupansky
-----Original Message-----
From: Ankit Murarka
Sent: Thursday, September 12, 2013 11:36 AM
To: java-user@lucene.apache.org
Subject: Re: Query type always Boolean Query even if * and ? are present.
Bingo....This has solved my case... Thanks a ton..!!
Does this mean any input containing spaces and query being parsed using
QueryParser will result in Query type as Boolean Query UNLESS white
space is escaped..
So if the input contains white space and parsed using QueryParser it
will eventually turn into Boolean since for each separate word it will
create a term and each term will be treated for Boolean Query.. ??
Can you please point any other possible pitfall when using QueryParser
and input containing special characters...
On 9/12/2013 8:59 PM, Jack Krupansky wrote:
You're not escaping white space, so your input will be a sequence of
terms, which should generate a BooleanQuery. What is the last clause of
the BQ? It should be your PrefixQuery.
-- Jack Krupansky
-----Original Message----- From: Ankit Murarka
Sent: Thursday, September 12, 2013 11:25 AM
To: java-user@lucene.apache.org
Subject: Re: Query type always Boolean Query even if * and ? are present.
If I remove the escape call from the function, then it works as
expected.. Prefix/Boolean/Wildcard..
But this is NOT what I want... The escape should be present else I will
get lexical error in case of Prefix/Boolean/Wildcard since my input will
definitely contain special characters...
Help needed..
TIA..
On 9/12/2013 8:52 PM, Ankit Murarka wrote:
I also tried it with this query:
<param name="user_name" value="USER_NAME_MENTIONED"/>*
I am still getting it as Boolean Query.. It should be Prefix...
On 9/12/2013 8:50 PM, Jack Krupansky wrote:
The trailing asterisk in your query input is escaped with a backslash,
so the query parser will not treat it as a wildcard.
-- Jack Krupansky
-----Original Message----- From: Ankit Murarka
Sent: Thursday, September 12, 2013 10:19 AM
To: java-user@lucene.apache.org
Subject: Query type always Boolean Query even if * and ? are present.
Hello.
I am faced with a trivial issue: Everytime my Query is being fired as a
Boolean Query...
Providing Input : <param name="user_name"
value="USER_NAME_MENTIONED"/>\*
This input is provided. Since this contains special characters I use
escape method of QueryParser (removed escaping for * and ? since they
are needed for WildCard and Prefix Searches.)
public static String escape(String s) {
System.out.println("CALLED");
StringBuilder sb = new StringBuilder();
try
{
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
// These characters are part of the query syntax and must be
escaped
if (c == '\\' || c == '+' || c == '-' || c == '!' || c == '('
|| c == ')' || c == ':'
|| c == '^' || c == '[' || c == ']' || c == '\"' || c ==
'{' || c == '}' || c == '~'
|| c == '|' || c == '&' || c == '/') {
sb.append('\\');
}
sb.append(c);
}
}catch(Exception e)
{
e.printStackTrace();
}
return sb.toString();
}
/*The function which is used to provide the HIT:*/
Directory directory=null;;
IndexReader reader=null;
IndexSearcher searcher=null;
Analyzer analyzer=null;
try
{
Analyzer analyzer = new
StandardAnalyzer(Version.LUCENE_44);
directory = FSDirectory.open(new
File(strMainIndexPath.replace("\\", "/")));
reader = DirectoryReader.open(directory); //location
where indexes are.
searcher = new IndexSearcher(reader);
System.out.println("Searching for '" + searchString +
"' using QueryParser");
QueryParser queryParser = new
QueryParser(Version.LUCENE_44,"contents",analyzer);
searchString=CommonMethods.escape(searchString);
//MENTIONED ABOVE
System.out.println("ESCAPE STRING AFTER THE ESCAPE
FUNCTION OF QUERYPARSER >>> " + searchString);
Query query = queryParser.parse(searchString);
System.out.println("Type of query: "
+query.getClass().getSimpleName()); //GETTING IT AS BOOLEAN ALWAYS..
The last output is always BOOLEAN Query... Even if I am appending * at
the end, the query is always Boolean...
I have to use QueryParser ONLY....
Absolutely no manipulation is done on string from being given as in
input to the string which is provided to this search function.
Kindly guide..
TIA.
--
Regards
Ankit Murarka
"What lies behind us and what lies before us are tiny matters compared with
what lies within us"
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