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<?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\Analysis\TokenFilter;
use ZendSearch\Lucene;
use ZendSearch\Lucene\Analysis\Token;
use ZendSearch\Lucene\Exception\InvalidArgumentException;
use ZendSearch\Lucene\Exception\RuntimeException;
/**
* Token filter that removes stop words. These words must be provided as array (set), example:
* $stopwords = array('the' => 1, 'an' => '1');
*
* We do recommend to provide all words in lowercase and concatenate this class after the lowercase filter.
*
* @category Zend
* @package Zend_Search_Lucene
* @subpackage Analysis
*/
class StopWords implements TokenFilterInterface
{
/**
* Stop Words
* @var array
*/
private $_stopSet;
/**
* Constructs new instance of this filter.
*
* @param array $stopwords array (set) of words that will be filtered out
*/
public function __construct($stopwords = array())
{
$this->_stopSet = array_flip($stopwords);
}
/**
* Normalize Token or remove it (if null is returned)
*
* @param \ZendSearch\Lucene\Analysis\Token $srcToken
* @return \ZendSearch\Lucene\Analysis\Token
*/
public function normalize(Token $srcToken)
{
if (array_key_exists($srcToken->getTermText(), $this->_stopSet)) {
return null;
} else {
return $srcToken;
}
}
/**
* Fills stopwords set from a text file. Each line contains one stopword, lines with '#' in the first
* column are ignored (as comments).
*
* You can call this method one or more times. New stopwords are always added to current set.
*
* @param string $filepath full path for text file with stopwords
* @throws \ZendSearch\Lucene\Exception\InvalidArgumentException
* @throws \ZendSearch\Lucene\Exception\RuntimeException
*/
public function loadFromFile($filepath = null)
{
if (! $filepath || ! file_exists($filepath)) {
throw new InvalidArgumentException('You have to provide valid file path');
}
$fd = fopen($filepath, "r");
if (! $fd) {
throw new RuntimeException('Cannot open file ' . $filepath);
}
while (!feof ($fd)) {
$buffer = trim(fgets($fd));
if (strlen($buffer) > 0 && $buffer[0] != '#') {
$this->_stopSet[$buffer] = 1;
}
}
if (!fclose($fd)) {
throw new RuntimeException('Cannot close file ' . $filepath);
}
}
}