it.unimi.dsi.mg4j.query.parser
Class QueryParser

java.lang.Object
  it.unimi.dsi.mg4j.query.parser.QueryParser

All Implemented Interfaces:

QueryParserConstants

public class QueryParser

extends Object

implements QueryParserConstants

This class is used to parse queries. You are supposed to create a query parser by giving a map that maps index names (called index aliases) to indices (instances of the Index class), and the name of the default index alias to be used. After that, you parse a query by using the parse(String) method.

Since:

0.9

Author:

Paolo Boldi, Sebastiano Vigna

Field Summary

Token	jj_nt
boolean	lookingAhead
Token	token
QueryParserTokenManager	token_source

Fields inherited from interface it.unimi.dsi.mg4j.query.parser.QueryParserConstants

AND, CLOSE_PAREN, COLON, DEFAULT, EOF, NOT, OPEN_PAREN, OR, QUOTE, SHARP, TILDA, tokenImage, WORD

Constructor Summary

QueryParser(Index index)
Creates a query parser for a single index.

QueryParser(InputStream stream)

QueryParser(Map indexMap, String defaultIndex)
Creates a query parser.

QueryParser(QueryParserTokenManager tm)

QueryParser(Reader stream)

Method Summary

DocumentIterator	andQuery(String indexAlias, boolean dontChange) Starting rule for an AND-query (the AND token is optional).
DocumentIterator	atomicQuery(String indexAlias, boolean dontChange) Starting rule for an atomic query.
DocumentIterator	atomicSimpleQuery(String indexAlias, boolean dontChange) Starting rule for an atomic simple query.
void	disable_tracing()
void	enable_tracing()
ParseException	generateParseException()
Token	getNextToken()
Token	getToken(int index)
DocumentIterator	parse(String query) Parses the given query, returning the corresponding query result.
DocumentIterator	query(String indexAlias, boolean dontChange) Starting rule for a OR-query.
DocumentIterator	quotedQuery(String indexAlias, boolean dontChange) Starting rule for a quoted query.
void	ReInit(InputStream stream)
void	ReInit(QueryParserTokenManager tm)
void	ReInit(Reader stream)
DocumentIterator	start(String indexAlias, boolean dontChange) Starting rule for a query.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

token_source

public QueryParserTokenManager token_source

token

public Token token

jj_nt

public Token jj_nt

lookingAhead

public boolean lookingAhead

Constructor Detail

QueryParser

public QueryParser(Map indexMap,
                   String defaultIndex)

Creates a query parser.

Parameters:

indexMap - a map from strings (index alias) to Index objects.

defaultIndex - the default index alias to be used when parsing the query.

QueryParser

public QueryParser(Index index)

Creates a query parser for a single index.

Parsers created by this constructor allow only nameless access, both in the query and in the interval-iterator methods.

Parameters:

index - the only index for the queries.

QueryParser

public QueryParser(InputStream stream)

QueryParser

public QueryParser(Reader stream)

QueryParser

public QueryParser(QueryParserTokenManager tm)

Method Detail

parse

public DocumentIterator parse(String query)
                       throws ParseException,
                              TokenMgrError,
                              IOException

Parses the given query, returning the corresponding query result.

Parameters:

query - the query to be parsed.

Returns:

the query result.

Throws:

ParseException - if a parse exception has taken place during query parsing.

TokenMgrError - if a tokenization exception has taken place during query parsing.

IOException - if a low-level I/O exception was thrown while trying to read some index.

start

public final DocumentIterator start(String indexAlias,
                                    boolean dontChange)
                             throws ParseException

Starting rule for a query.

Parameters:

indexAlias - the index alias for the default index to be used for the query that is going to be parsed.

dontChange - if true, the query cannot contain index selectors other than indexAlias.

Returns:

the result of the query.

Throws:

ParseException

query

public final DocumentIterator query(String indexAlias,
                                    boolean dontChange)
                             throws ParseException

Starting rule for a OR-query.

Parameters:

indexAlias - the index alias for the default index to be used for the query that is going to be parsed.

dontChange - if true, the query cannot contain index selectors other than indexAlias.

Returns:

the result of the query.

Throws:

ParseException

andQuery

public final DocumentIterator andQuery(String indexAlias,
                                       boolean dontChange)
                                throws ParseException

Starting rule for an AND-query (the AND token is optional).

Parameters:

indexAlias - the index alias for the default index to be used for the query that is going to be parsed.

dontChange - if true, the query cannot contain index selectors other than indexAlias.

Returns:

the result of the query.

Throws:

ParseException

quotedQuery

public final DocumentIterator quotedQuery(String indexAlias,
                                          boolean dontChange)
                                   throws ParseException

Starting rule for a quoted query. Subqueries cannot change index.

Parameters:

indexAlias - the index alias for the default index to be used for the query that is going to be parsed.

dontChange - if true, the query cannot contain index selectors other than indexAlias.

Returns:

the result of the query.

Throws:

ParseException

atomicQuery

public final DocumentIterator atomicQuery(String indexAlias,
                                          boolean dontChange)
                                   throws ParseException

Starting rule for an atomic query. May be either an atomic simple query or a quoted query. It can optionally contain an index selector and a low-pass limit.

Parameters:

indexAlias - the index alias for the default index to be used for the query that is going to be parsed.

dontChange - if true, the query cannot contain index selectors other than indexAlias.

Returns:

the result of the query.

Throws:

ParseException

atomicSimpleQuery

public final DocumentIterator atomicSimpleQuery(String indexAlias,
                                                boolean dontChange)
                                         throws ParseException

Starting rule for an atomic simple query. May be either a word or a query enclosed within parentheses.

Parameters:

indexAlias - the index alias for the default index to be used for the query that is going to be parsed.

dontChange - if true, the query cannot contain index selectors other than indexAlias.

Returns:

the result of the query.

Throws:

ParseException

ReInit

public void ReInit(InputStream stream)

ReInit

public void ReInit(Reader stream)

ReInit

public void ReInit(QueryParserTokenManager tm)

getNextToken

public final Token getNextToken()

getToken

public final Token getToken(int index)

generateParseException

public ParseException generateParseException()

enable_tracing

public final void enable_tracing()

disable_tracing

public final void disable_tracing()