<?php
/**
* Zend Framework (http://framework.zend.com/)
*
* @link http://github.com/zendframework/zf2 for the canonical source repository
* @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @package Zend_Search
*/
namespace ZendSearch\Lucene\Search;
use ZendSearch\Lucene;
/**
* @category Zend
* @package Zend_Search_Lucene
* @subpackage Search
*/
class BooleanExpressionRecognizer extends Lucene\AbstractFSM
{
/** State Machine states */
const ST_START = 0;
const ST_LITERAL = 1;
const ST_NOT_OPERATOR = 2;
const ST_AND_OPERATOR = 3;
const ST_OR_OPERATOR = 4;
/** Input symbols */
const IN_LITERAL = 0;
const IN_NOT_OPERATOR = 1;
const IN_AND_OPERATOR = 2;
const IN_OR_OPERATOR = 3;
/**
* NOT operator signal
*
* @var boolean
*/
private $_negativeLiteral = false;
/**
* Current literal
*
* @var mixed
*/
private $_literal;
/**
* Set of boolean query conjunctions
*
* Each conjunction is an array of conjunction elements
* Each conjunction element is presented with two-elements array:
* array(<literal>, <is_negative>)
*
* So, it has a structure:
* array( array( array(<literal>, <is_negative>), // first literal of first conjuction
* array(<literal>, <is_negative>), // second literal of first conjuction
* ...
* array(<literal>, <is_negative>)
* ), // end of first conjuction
* array( array(<literal>, <is_negative>), // first literal of second conjuction
* array(<literal>, <is_negative>), // second literal of second conjuction
* ...
* array(<literal>, <is_negative>)
* ), // end of second conjuction
* ...
* ) // end of structure
*
* @var array
*/
private $_conjunctions = array();
/**
* Current conjuction
*
* @var array
*/
private $_currentConjunction = array();
/**
* Object constructor
*/
public function __construct()
{
parent::__construct( array(self::ST_START,
self::ST_LITERAL,
self::ST_NOT_OPERATOR,
self::ST_AND_OPERATOR,
self::ST_OR_OPERATOR),
array(self::IN_LITERAL,
self::IN_NOT_OPERATOR,
self::IN_AND_OPERATOR,
self::IN_OR_OPERATOR));
$emptyOperatorAction = new Lucene\FSMAction($this, 'emptyOperatorAction');
$emptyNotOperatorAction = new Lucene\FSMAction($this, 'emptyNotOperatorAction');
$this->addRules(array( array(self::ST_START, self::IN_LITERAL, self::ST_LITERAL),
array(self::ST_START, self::IN_NOT_OPERATOR, self::ST_NOT_OPERATOR),
array(self::ST_LITERAL, self::IN_AND_OPERATOR, self::ST_AND_OPERATOR),
array(self::ST_LITERAL, self::IN_OR_OPERATOR, self::ST_OR_OPERATOR),
array(self::ST_LITERAL, self::IN_LITERAL, self::ST_LITERAL, $emptyOperatorAction),
array(self::ST_LITERAL, self::IN_NOT_OPERATOR, self::ST_NOT_OPERATOR, $emptyNotOperatorAction),
array(self::ST_NOT_OPERATOR, self::IN_LITERAL, self::ST_LITERAL),
array(self::ST_AND_OPERATOR, self::IN_LITERAL, self::ST_LITERAL),
array(self::ST_AND_OPERATOR, self::IN_NOT_OPERATOR, self::ST_NOT_OPERATOR),
array(self::ST_OR_OPERATOR, self::IN_LITERAL, self::ST_LITERAL),
array(self::ST_OR_OPERATOR, self::IN_NOT_OPERATOR, self::ST_NOT_OPERATOR),
));
$notOperatorAction = new Lucene\FSMAction($this, 'notOperatorAction');
$orOperatorAction = new Lucene\FSMAction($this, 'orOperatorAction');
$literalAction = new Lucene\FSMAction($this, 'literalAction');
$this->addEntryAction(self::ST_NOT_OPERATOR, $notOperatorAction);
$this->addEntryAction(self::ST_OR_OPERATOR, $orOperatorAction);
$this->addEntryAction(self::ST_LITERAL, $literalAction);
}
/**
* Process next operator.
*
* Operators are defined by class constants: IN_AND_OPERATOR, IN_OR_OPERATOR and IN_NOT_OPERATOR
*
* @param integer $operator
*/
public function processOperator($operator)
{
$this->process($operator);
}
/**
* Process expression literal.
*
* @param integer $operator
*/
public function processLiteral($literal)
{
$this->_literal = $literal;
$this->process(self::IN_LITERAL);
}
/**
* Finish an expression and return result
*
* Result is a set of boolean query conjunctions
*
* Each conjunction is an array of conjunction elements
* Each conjunction element is presented with two-elements array:
* array(<literal>, <is_negative>)
*
* So, it has a structure:
* array( array( array(<literal>, <is_negative>), // first literal of first conjuction
* array(<literal>, <is_negative>), // second literal of first conjuction
* ...
* array(<literal>, <is_negative>)
* ), // end of first conjuction
* array( array(<literal>, <is_negative>), // first literal of second conjuction
* array(<literal>, <is_negative>), // second literal of second conjuction
* ...
* array(<literal>, <is_negative>)
* ), // end of second conjuction
* ...
* ) // end of structure
*
* @throws \ZendSearch\Lucene\Exception\UnexpectedValueException
* @return array
*/
public function finishExpression()
{
if ($this->getState() != self::ST_LITERAL) {
throw new Lucene\Exception\UnexpectedValueException('Literal expected.');
}
$this->_conjunctions[] = $this->_currentConjunction;
return $this->_conjunctions;
}
/*********************************************************************
* Actions implementation
*********************************************************************/
/**
* default (omitted) operator processing
*/
public function emptyOperatorAction()
{
if (QueryParser::getDefaultOperator() == QueryParser::B_AND) {
// Do nothing
} else {
$this->orOperatorAction();
}
// Process literal
$this->literalAction();
}
/**
* default (omitted) + NOT operator processing
*/
public function emptyNotOperatorAction()
{
if (QueryParser::getDefaultOperator() == QueryParser::B_AND) {
// Do nothing
} else {
$this->orOperatorAction();
}
// Process NOT operator
$this->notOperatorAction();
}
/**
* NOT operator processing
*/
public function notOperatorAction()
{
$this->_negativeLiteral = true;
}
/**
* OR operator processing
* Close current conjunction
*/
public function orOperatorAction()
{
$this->_conjunctions[] = $this->_currentConjunction;
$this->_currentConjunction = array();
}
/**
* Literal processing
*/
public function literalAction()
{
// Add literal to the current conjunction
$this->_currentConjunction[] = array($this->_literal, !$this->_negativeLiteral);
// Switch off negative signal
$this->_negativeLiteral = false;
}
}