no.sesat.search.query.parser
Class AbstractQueryParser

java.lang.Object
  no.sesat.search.query.parser.AbstractQueryParser

All Implemented Interfaces:

QueryParser

Direct Known Subclasses:

QueryParserImpl

public abstract class AbstractQueryParser
extends Object
implements QueryParser

Abstract helper for implementing a QueryParser Provides default implementation to get the query object.

Version:

$Id: AbstractQueryParser.java 7225 2009-04-09 00:32:20Z ssmiweve $

Nested Class Summary

Nested classes/interfaces inherited from interface no.sesat.search.query.parser.QueryParser

QueryParser.Context

Field Summary

protected QueryParser.Context	context the context this query parser implementation must work against.
protected static String	ERR_EMPTY_CONTEXT Error message when the parser tries to parse an empty query string.
protected static Logger	LOG Protected so an .jj file implementing this class can reuse.
static String	OPERATOR_REGEX
static String	SKIP_REGEX

Fields inherited from interface no.sesat.search.query.parser.QueryParser

OPERATORS, SKIP_CHARACTER_RANGES

Constructor Summary

AbstractQueryParser()

Method Summary

protected String	balance(String query, char leftChar, char rightChar) Ensure that for every leftChar there is a matching rightChar.
protected QueryParser.Context	createContext(String input) Create a new context the return the argument on any call to its getQueryString() method.
protected void	enterMethod(String method, Token token) Debugging method for tracing a method entry.
protected String	even(String query, char c) Ensure that there are a even number of c characters in the phrase, otherwise remove all occurences of c.
protected void	exitMethod() Debugging method for tracing a method exit.
protected String	fixFloatingHyphon(String query) HACK because a floating hyphon is interpretted as a NotClause.
Query	getQuery() Get the query object.
protected String	numberNeedsTrailingSpace(String query) HACK because phone numbers and organisation numbers need to finish with a space.
abstract Clause	parse() do the actual parsing.
protected abstract void	ReInit(Reader reader)

Methods inherited from class java.lang.Object

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

Field Detail

SKIP_REGEX

public static final String SKIP_REGEX

OPERATOR_REGEX

public static final String OPERATOR_REGEX

LOG

protected static final Logger LOG

Protected so an .jj file implementing this class can reuse.

ERR_EMPTY_CONTEXT

protected static final String ERR_EMPTY_CONTEXT

Error message when the parser tries to parse an empty query string.

See Also:

Constant Field Values

context

protected transient QueryParser.Context context

the context this query parser implementation must work against.

Constructor Detail

AbstractQueryParser

public AbstractQueryParser()

Method Detail

parse

public abstract Clause parse()
                      throws ParseException

do the actual parsing. This method shouldn't be public but that's the way javacc creates it unfortunately.

Returns:

the clause hierarchy ready to wrap a Query around.

Throws:

ParseException - when parsing the inputted query string.

getQuery

public Query getQuery()

Get the query object. A call to this method initiates the parse() method if the query hasn't already been built.

Specified by:

getQuery in interface QueryParser

Returns:

the Query object, ready to use.

createContext

protected final QueryParser.Context createContext(String input)

Create a new context the return the argument on any call to its getQueryString() method.

Parameters:

input - the query string returned from the created context's getQueryString() method.

Returns:

new content supplying access to query string "input"

enterMethod

protected final void enterMethod(String method,
                                 Token token)

Debugging method for tracing a method entry.

Parameters:

method - the name of the method

exitMethod

protected final void exitMethod()

Debugging method for tracing a method exit.

balance

protected final String balance(String query,
                               char leftChar,
                               char rightChar)

Ensure that for every leftChar there is a matching rightChar. Otherwise remove all occurences of both leftChar and rightChar.

Parameters:

query -

leftChar -

rightChar -

Returns:

even

protected final String even(String query,
                            char c)

Ensure that there are a even number of c characters in the phrase, otherwise remove all occurences of c.

Parameters:

query -

c - the character to ensure has an even occurence count.

Returns:

unchanged or changes string.

numberNeedsTrailingSpace

protected final String numberNeedsTrailingSpace(String query)

HACK because phone numbers and organisation numbers need to finish with a space. SEARCH-672

Parameters:

query -

Returns:

fixFloatingHyphon

protected final String fixFloatingHyphon(String query)

HACK because a floating hyphon is interpretted as a NotClause. Sesam syntax requires the hyphon to be adjacent, without whitespace, to the next term. SEARCH-3390

Parameters:

query -

Returns:

ReInit

protected abstract void ReInit(Reader reader)