Nepomuk2::Query::QueryParser Class Reference

#include <Nepomuk2/Query/QueryParser>

Public Types
enum	ParserFlag { NoParserFlags = 0x0, QueryTermGlobbing = 0x1, DetectFilenamePattern = 0x2 }

Public Member Functions
	QueryParser ()
	~QueryParser ()
QList< Types::Property >	matchProperty (const QString &fieldName) const
Query	parse (const QString &query) const
Query	parse (const QString &query, ParserFlags flags) const

Static Public Member Functions
static Query	parseQuery (const QString &query)
static Query	parseQuery (const QString &query, ParserFlags flags)

Detailed Description

Parser for desktop user queries.

Warning

This is NOT a SPARQL parser.

The QueryParser can be used to parse user queries, ie. queries that the user would enter in any search interface, and convert them into Query instances.

The syntax is fairly simple: plain strings match to LiteralTerm terms, URIs need to be N3-encoded, when using white space parenthesis need to be put around properties and values, terms can be excluded via '-'.

Examples

Query everything that contains the term "nepomuk":

nepomuk

Query everything that contains both the terms "Hello" and "World":

Hello World

Query everything that contains the term "Hello World":

"Hello World"

Query everything that has a tag whose label matches "nepomuk" (actually this is where Query::resolveProperties would match "hastag" to nao:hasTag):

hastag:nepomuk

Query everything that has a tag labeled "nepomuk" or a tag labeled "scribo:

hastag:nepomuk OR hastag:scribo

Query everything that has a tag labeled "nepomuk" but not a tag labeled "scribo":

+hastag:nepomuk AND -hastag:scribo

The parser can handle one special case of nesting (TODO: implement a "real" parser) which matches all resources that are related to a resource which in turn has a certain property:

related:(hastag:nepomuk)

Author

Sebastian Trueg trueg.nosp@m.@kde.nosp@m..org

Since

4.4

Definition at line 90 of file queryparser.h.

Member Enumeration Documentation

enum Nepomuk2::Query::QueryParser::ParserFlag

Flags to change the behaviour of the parser.

Since

4.5

Enumerator
NoParserFlags	No flags. Default for parse()
QueryTermGlobbing	Make each full text term use a '*' wildcard to match longer strings ('foobar' is matched by 'foob*'). Be aware that the query engine needs at least 4 chars to do globbing though. This is disabled by default.
DetectFilenamePattern	Try to detect filename pattern like *.mp3 or hello*.txt and create appropriate ComparisonTerm instances using ComparisonTerm::Regexp instead of ComparisonTerm::Contains. Since 4.6

Definition at line 108 of file queryparser.h.

Constructor & Destructor Documentation

Nepomuk2::Query::QueryParser::QueryParser

(

)

Create a new query parser.

Definition at line 538 of file queryparser.cpp.

Nepomuk2::Query::QueryParser::~QueryParser

(

)

Destructor.

Definition at line 572 of file queryparser.cpp.

Member Function Documentation

QList< Nepomuk2::Types::Property > Nepomuk2::Query::QueryParser::matchProperty

(

const QString &

fieldName

)

const

Try to match a field name as used in a query string to actual properties.

The matching is cached inside the Query instance for fast subsequent lookups.

Example:

hastag:nepomuk

Returns

A list of properties that match fieldName or an empty list in case nothing was matched.

This method is used by parse() to match properties used in user queries.

Definition at line 578 of file queryparser.cpp.

Nepomuk2::Query::Query Nepomuk2::Query::QueryParser::parse

(

const QString &

query

)

const

Parse a user query.

Returns

The parsed query or an invalid Query object in case the parsing failed.

Definition at line 626 of file queryparser.cpp.

Nepomuk2::Query::Query Nepomuk2::Query::QueryParser::parse	(	const QString &	query,
		ParserFlags	flags
	)		const

Parse a user query.

Parameters

query	The query string to parse
flags	a set of flags influencing the parsing process.

Returns

The parsed query or an invalid Query object in case the parsing failed.

Since

4.5

Definition at line 632 of file queryparser.cpp.

Nepomuk2::Query::Query Nepomuk2::Query::QueryParser::parseQuery ( const QString &  query )

static

Convenience method to quickly parse a query without creating an object.

Returns

The parsed query or an invalid Query object in case the parsing failed.

Definition at line 815 of file queryparser.cpp.

Nepomuk2::Query::Query Nepomuk2::Query::QueryParser::parseQuery ( const QString &  query, ParserFlags  flags  )

static

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters

query	The query string to parse
flags	a set of flags influencing the parsing process.

Since

4.6

Definition at line 823 of file queryparser.cpp.

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The documentation for this class was generated from the following files:

• queryparser.h
• queryparser.cpp