class.SurveyMetricQuestion.php

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<?php
 /*
   +----------------------------------------------------------------------------+
   | ILIAS open source                                                          |
   +----------------------------------------------------------------------------+
   | Copyright (c) 1998-2001 ILIAS open source, University of Cologne           |
   |                                                                            |
   | This program is free software; you can redistribute it and/or              |
   | modify it under the terms of the GNU General Public License                |
   | as published by the Free Software Foundation; either version 2             |
   | of the License, or (at your option) any later version.                     |
   |                                                                            |
   | This program is distributed in the hope that it will be useful,            |
   | but WITHOUT ANY WARRANTY; without even the implied warranty of             |
   | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              |
   | GNU General Public License for more details.                               |
   |                                                                            |
   | You should have received a copy of the GNU General Public License          |
   | along with this program; if not, write to the Free Software                |
   | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
   +----------------------------------------------------------------------------+
*/

include_once "./Modules/SurveyQuestionPool/classes/class.SurveyQuestion.php";

class SurveyMetricQuestion extends SurveyQuestion 
{
        const SUBTYPE_NON_RATIO = 3;
        const SUBTYPE_RATIO_NON_ABSOLUTE = 4;
        const SUBTYPE_RATIO_ABSOLUTE = 5;
        
  var $subtype;

  var $minimum;

  var $maximum;

        function SurveyMetricQuestion(
                $title = "",
                $description = "",
                $author = "",
                $questiontext = "",
                $owner = -1,
                $subtype = self::SUBTYPE_NON_RATIO
        )
        {
                $this->SurveyQuestion($title, $description, $author, $questiontext, $owner);
                $this->subtype = $subtype;
                $this->minimum = "";
                $this->maximum = "";
        }
        
  function setSubtype($subtype = self::SUBTYPE_NON_RATIO) 
        {
    $this->subtype = $subtype;
  }

  function setMinimum($minimum = 0) 
        {
           if($minimum !== NULL)
          {
                  $minimum = (float)$minimum;            
          }
           if(!$minimum)
                {
                        $minimum = NULL;
                }
    $this->minimum = $minimum;
  }

  function setMaximum($maximum = "") 
        {
            if($maximum !== NULL)
          {
                  $maximum = (float)$maximum;
          }
           if(!$maximum)
                {
                        $maximum = NULL;
                }
    $this->maximum = $maximum;
  }

  function getSubtype() 
        {
    return $this->subtype;
  }
        
        function getMinimum() 
        {
                if ((strlen($this->minimum) == 0) && ($this->getSubtype() > 3))
                {
                        $this->minimum = 0;
                }
                return (strlen($this->minimum)) ? $this->minimum : NULL;
        }
        
        function getMaximum() 
        {
                return (strlen($this->maximum)) ? $this->maximum : NULL;
        }
        
        function _getQuestionDataArray($id)
        {
                global $ilDB;
                
                $result = $ilDB->queryF("SELECT svy_question.*, " . $this->getAdditionalTableName() . ".* FROM svy_question, " . $this->getAdditionalTableName() . " WHERE svy_question.question_id = %s AND svy_question.question_id = " . $this->getAdditionalTableName() . ".question_fi",
                        array('integer'),
                        array($id)
                );
                if ($result->numRows() == 1)
                {
                        return $ilDB->fetchAssoc($result);
                }
                else
                {
                        return array();
                }
        }
        
        function loadFromDb($id) 
        {
                global $ilDB;

                $result = $ilDB->queryF("SELECT svy_question.*, " . $this->getAdditionalTableName() . ".* FROM svy_question LEFT JOIN " . $this->getAdditionalTableName() . " ON " . $this->getAdditionalTableName() . ".question_fi = svy_question.question_id WHERE svy_question.question_id = %s",
                        array('integer'),
                        array($id)
                );
                if ($result->numRows() == 1) 
                {
                        $data = $ilDB->fetchAssoc($result);
                        $this->setId($data["question_id"]);
                        $this->setTitle($data["title"]);
                        $this->setDescription($data["description"]);
                        $this->setObjId($data["obj_fi"]);
                        $this->setAuthor($data["author"]);
                        $this->setOwner($data["owner_fi"]);
                        $this->label = $data['label'];
                        include_once("./Services/RTE/classes/class.ilRTE.php");
                        $this->setQuestiontext(ilRTE::_replaceMediaObjectImageSrc($data["questiontext"], 1));
                        $this->setObligatory($data["obligatory"]);
                        $this->setComplete($data["complete"]);
                        $this->setOriginalId($data["original_id"]);
                        $this->setSubtype($data["subtype"]);

                        $result = $ilDB->queryF("SELECT svy_variable.* FROM svy_variable WHERE svy_variable.question_fi = %s",
                                array('integer'),
                                array($id)
                        );
                        if ($result->numRows() > 0) 
                        {
                                if ($data = $ilDB->fetchAssoc($result)) 
                                {
                                        $this->minimum = $data["value1"];
                                        if (($data["value2"] < 0) or (strcmp($data["value2"], "") == 0))
                                        {
                                                $this->maximum = "";
                                        }
                                        else
                                        {
                                                $this->maximum = $data["value2"];
                                        }
                                }
                        }
                }
                parent::loadFromDb($id);
        }

        function isComplete()
        {
                if (
                        strlen($this->getTitle()) &&
                        strlen($this->getAuthor()) &&
                        strlen($this->getQuestiontext())
                )
                {
                        return 1;
                }
                else
                {
                        return 0;
                }
        }
        
  function saveToDb($original_id = "")
  {
                global $ilDB;

                $affectedRows = parent::saveToDb($original_id);
                if ($affectedRows == 1) 
                {
                        $affectedRows = $ilDB->manipulateF("DELETE FROM " . $this->getAdditionalTableName() . " WHERE question_fi = %s",
                                array('integer'),
                                array($this->getId())
                        );
                        $affectedRows = $ilDB->manipulateF("INSERT INTO " . $this->getAdditionalTableName() . " (question_fi, subtype) VALUES (%s, %s)",
                                array('integer', 'text'),
                                array($this->getId(), $this->getSubType())
                        );

                        // saving material uris in the database
                        $this->saveMaterial();
                        
                        // save categories
                        $affectedRows = $ilDB->manipulateF("DELETE FROM svy_variable WHERE question_fi = %s",
                                array('integer'),
                                array($this->getId())
                        );

                        if (preg_match("/[\D]/", $this->maximum) or (strcmp($this->maximum, "&infin;") == 0))
                        {
                                $max = -1;
                        }
                        else
                        {
                                $max = $this->getMaximum();
                        }
                        $next_id = $ilDB->nextId('svy_variable');
                        $affectedRows = $ilDB->manipulateF("INSERT INTO svy_variable (variable_id, category_fi, question_fi, value1, value2, sequence, tstamp) VALUES (%s, %s, %s, %s, %s, %s, %s)",
                                array('integer','integer','integer','float','float','integer','integer'),
                                array($next_id, 0, $this->getId(), $this->getMinimum(), $max, 0, time())
                        );
                } 
  }
        
        function toXML($a_include_header = TRUE, $obligatory_state = "")
        {
                include_once("./Services/Xml/classes/class.ilXmlWriter.php");
                $a_xml_writer = new ilXmlWriter;
                $a_xml_writer->xmlHeader();
                $this->insertXML($a_xml_writer, $a_include_header, $obligatory_state);
                $xml = $a_xml_writer->xmlDumpMem(FALSE);
                if (!$a_include_header)
                {
                        $pos = strpos($xml, "?>");
                        $xml = substr($xml, $pos + 2);
                }
                return $xml;
        }
        
        function insertXML(&$a_xml_writer, $a_include_header = TRUE, $obligatory_state = "")
        {
                $attrs = array(
                        "id" => $this->getId(),
                        "title" => $this->getTitle(),
                        "type" => $this->getQuestiontype(),
                        "subtype" => $this->getSubtype(),
                        "obligatory" => $this->getObligatory()
                );
                $a_xml_writer->xmlStartTag("question", $attrs);
                
                $a_xml_writer->xmlElement("description", NULL, $this->getDescription());
                $a_xml_writer->xmlElement("author", NULL, $this->getAuthor());
                $a_xml_writer->xmlStartTag("questiontext");
                $this->addMaterialTag($a_xml_writer, $this->getQuestiontext());
                $a_xml_writer->xmlEndTag("questiontext");

                $a_xml_writer->xmlStartTag("responses");
                switch ($this->getSubtype())
                {
                        case 3:
                                $attrs = array(
                                        "id" => "0",
                                        "format" => "double"
                                );
                                if (strlen($this->getMinimum()))
                                {
                                        $attrs["min"] = $this->getMinimum();
                                }
                                if (strlen($this->getMaximum()))
                                {
                                        $attrs["max"] = $this->getMaximum();
                                }
                                break;
                        case 4:
                                $attrs = array(
                                        "id" => "0",
                                        "format" => "double"
                                );
                                if (strlen($this->getMinimum()))
                                {
                                        $attrs["min"] = $this->getMinimum();
                                }
                                if (strlen($this->getMaximum()))
                                {
                                        $attrs["max"] = $this->getMaximum();
                                }
                                break;
                        case 5:
                                $attrs = array(
                                        "id" => "0",
                                        "format" => "integer"
                                );
                                if (strlen($this->getMinimum()))
                                {
                                        $attrs["min"] = $this->getMinimum();
                                }
                                if (strlen($this->getMaximum()))
                                {
                                        $attrs["max"] = $this->getMaximum();
                                }
                                break;
                }
                $a_xml_writer->xmlStartTag("response_num", $attrs);
                $a_xml_writer->xmlEndTag("response_num");

                $a_xml_writer->xmlEndTag("responses");

                if (count($this->material))
                {
                        if (preg_match("/il_(\d*?)_(\w+)_(\d+)/", $this->material["internal_link"], $matches))
                        {
                                $attrs = array(
                                        "label" => $this->material["title"]
                                );
                                $a_xml_writer->xmlStartTag("material", $attrs);
                                $intlink = "il_" . IL_INST_ID . "_" . $matches[2] . "_" . $matches[3];
                                if (strcmp($matches[1], "") != 0)
                                {
                                        $intlink = $this->material["internal_link"];
                                }
                                $a_xml_writer->xmlElement("mattext", NULL, $intlink);
                                $a_xml_writer->xmlEndTag("material");
                        }
                }
                
                $a_xml_writer->xmlEndTag("question");
        }

        function getQuestionTypeID()
        {
                global $ilDB;
                $result = $ilDB->queryF("SELECT questiontype_id FROM svy_qtype WHERE type_tag = %s",
                        array('text'),
                        array($this->getQuestionType())
                );
                $row = $ilDB->fetchAssoc($result);
                return $row["questiontype_id"];
        }

        function getQuestionType()
        {
                return "SurveyMetricQuestion";
        }
        
        function getAdditionalTableName()
        {
                return "svy_qst_metric";
        }
        
        function &getWorkingDataFromUserInput($post_data)
        {
                $entered_value = $post_data[$this->getId() . "_metric_question"];
                $data = array();
                if (strlen($entered_value))
                {
                        array_push($data, array("value" => $entered_value));
                }
                return $data;
        }
        
        function checkUserInput($post_data, $survey_id)
        {
                $entered_value = $post_data[$this->getId() . "_metric_question"];
                // replace german notation with international notation
                $entered_value = str_replace(",", ".", $entered_value);
                
                if ((!$this->getObligatory($survey_id)) && (strlen($entered_value) == 0)) return "";
                
                if (strlen($entered_value) == 0) return $this->lng->txt("survey_question_obligatory");
                
                if (strlen($this->getMinimum()))
                {
                        if ($entered_value < $this->getMinimum())
                        {
                                return $this->lng->txt("metric_question_out_of_bounds");
                        }
                }

                if (strlen($this->getMaximum()))
                {
                        if (($this->getMaximum() == 1) && ($this->getMaximum() < $this->getMinimum()))
                        {
                                // old &infty; values as maximum
                        }
                        else
                        {
                                if ($entered_value > $this->getMaximum())
                                {
                                        return $this->lng->txt("metric_question_out_of_bounds");
                                }
                        }
                }

                if (!is_numeric($entered_value))
                {
                        return $this->lng->txt("metric_question_not_a_value");
                }

                if (($this->getSubType() == self::SUBTYPE_RATIO_ABSOLUTE) && (intval($entered_value) != doubleval($entered_value)))
                {
                        return $this->lng->txt("metric_question_floating_point");
                }
                return "";
        }
        
        public function saveRandomData($active_id)
        {
                global $ilDB;
                // single response
                $number = rand($this->getMinimum(), (strlen($this->getMaximum())) ? $this->getMaximum() : 100);
                $next_id = $ilDB->nextId('svy_answer');
                $affectedRows = $ilDB->manipulateF("INSERT INTO svy_answer (answer_id, question_fi, active_fi, value, textanswer, tstamp) VALUES (%s, %s, %s, %s, %s, %s)",
                        array('integer','integer','integer','float','text','integer'),
                        array($next_id, $this->getId(), $active_id, $number, NULL, time())
                );
        }

        function saveUserInput($post_data, $active_id, $a_return = false)
        {
                global $ilDB;
                
                $entered_value = $post_data[$this->getId() . "_metric_question"];
                
                // replace german notation with international notation
                $entered_value = str_replace(",", ".", $entered_value);
                
                if($a_return)
                {
                        return array(array("value"=>$entered_value, "textanswer"=>null));
                }
                if (strlen($entered_value) == 0) return;
                
                $next_id = $ilDB->nextId('svy_answer');
                $affectedRows = $ilDB->manipulateF("INSERT INTO svy_answer (answer_id, question_fi, active_fi, value, textanswer, tstamp) VALUES (%s, %s, %s, %s, %s, %s)",
                        array('integer','integer','integer','float','text','integer'),
                        array($next_id, $this->getId(), $active_id, (strlen($entered_value)) ? $entered_value : NULL, NULL, time())
                );
        }
        
        function &getCumulatedResults($survey_id, $nr_of_users, $finished_ids)
        {
                global $ilDB;
                
                $question_id = $this->getId();
                
                $result_array = array();
                $cumulated = array();

                $sql = "SELECT svy_answer.* FROM svy_answer".
                        " JOIN svy_finished ON (svy_finished.finished_id = svy_answer.active_fi)".
                        " WHERE svy_answer.question_fi = ".$ilDB->quote($question_id, "integer").
                        " AND svy_finished.survey_fi = ".$ilDB->quote($survey_id, "integer");           
                if($finished_ids)
                {
                        $sql .= " AND ".$ilDB->in("svy_finished.finished_id", $finished_ids, "", "integer");
                }

                $result = $ilDB->query($sql);           
                while ($row = $ilDB->fetchAssoc($result))
                {
                        $cumulated[$row["value"]]++;
                }
                asort($cumulated, SORT_NUMERIC);
                end($cumulated);
                $numrows = $result->numRows();
                $result_array["USERS_ANSWERED"] = $result->numRows();
                $result_array["USERS_SKIPPED"] = $nr_of_users - $result->numRows();
                if(sizeof($cumulated))
                {
                        $result_array["MODE"] = key($cumulated);
                        $result_array["MODE_VALUE"] = key($cumulated);
                        $result_array["MODE_NR_OF_SELECTIONS"] = $cumulated[key($cumulated)];
                        ksort($cumulated, SORT_NUMERIC);
                }
                $counter = 0;
                foreach ($cumulated as $value => $nr_of_users)
                {
                        $percentage = 0;
                        if ($numrows > 0)
                        {
                                $percentage = (float)($nr_of_users/$numrows);
                        }
                        $result_array["values"][$counter++] = array("value" => $value, "selected" => (int)$nr_of_users, "percentage" => $percentage);
                }
                $median = array();
                $total = 0;
                $x_i = 0;
                $p_i = 1;
                $x_i_inv = 0;
                $sum_part_zero = false;
                foreach ($cumulated as $value => $key)
                {
                        $total += $key;
                        for ($i = 0; $i < $key; $i++)
                        {
                                array_push($median, $value);
                                $x_i += $value;
                                $p_i *= $value;
                                if ($value != 0)
                                {
                                        $sum_part_zero = true;
                                        $x_i_inv += 1/$value;
                                }
                        }
                }
                if ($total > 0)
                {
                        if (($total % 2) == 0)
                        {
                                $median_value = 0.5 * ($median[($total/2)-1] + $median[($total/2)]);
                        }
                        else
                        {
                                $median_value = $median[(($total+1)/2)-1];
                        }
                }
                else
                {
                        $median_value = "";
                }
                if ($total > 0)
                {
                        if (($x_i/$total) == (int)($x_i/$total))
                        {
                                $result_array["ARITHMETIC_MEAN"] = $x_i/$total;
                        }
                        else
                        {
                                $result_array["ARITHMETIC_MEAN"] = sprintf("%.2f", $x_i/$total);
                        }
                }
                else
                {
                        $result_array["ARITHMETIC_MEAN"] = "";
                }
                $result_array["MEDIAN"] = $median_value;
                $result_array["QUESTION_TYPE"] = "SurveyMetricQuestion";
                return $result_array;
        }
        
        function setExportDetailsXLS(&$workbook, &$format_title, &$format_bold, &$eval_data, $export_label)
        {
                include_once ("./Services/Excel/classes/class.ilExcelUtils.php");
                $worksheet =& $workbook->addWorksheet();
                $rowcounter = 0;
                switch ($export_label)
                {
                        case 'label_only':
                                $worksheet->writeString(0, 0, ilExcelUtils::_convert_text($this->lng->txt("label")), $format_bold);
                                $worksheet->writeString(0, 1, ilExcelUtils::_convert_text($this->label));
                                break;
                        case 'title_only':
                                $worksheet->writeString(0, 0, ilExcelUtils::_convert_text($this->lng->txt("title")), $format_bold);
                                $worksheet->writeString(0, 1, ilExcelUtils::_convert_text($this->getTitle()));
                                break;
                        default:
                                $worksheet->writeString(0, 0, ilExcelUtils::_convert_text($this->lng->txt("title")), $format_bold);
                                $worksheet->writeString(0, 1, ilExcelUtils::_convert_text($this->getTitle()));
                                $rowcounter++;
                                $worksheet->writeString($rowcounter, 0, ilExcelUtils::_convert_text($this->lng->txt("label")), $format_bold);
                                $worksheet->writeString($rowcounter, 1, ilExcelUtils::_convert_text($this->label));
                                break;
                }
                $rowcounter++;
                $worksheet->writeString($rowcounter, 0, ilExcelUtils::_convert_text($this->lng->txt("question")), $format_bold);
                $worksheet->writeString($rowcounter, 1, ilExcelUtils::_convert_text($this->getQuestiontext()));
                $rowcounter++;
                $worksheet->writeString($rowcounter, 0, ilExcelUtils::_convert_text($this->lng->txt("question_type")), $format_bold);
                $worksheet->writeString($rowcounter, 1, ilExcelUtils::_convert_text($this->lng->txt($this->getQuestionType())));
                $rowcounter++;
                $worksheet->writeString($rowcounter, 0, ilExcelUtils::_convert_text($this->lng->txt("users_answered")), $format_bold);
                $worksheet->write($rowcounter, 1, $eval_data["USERS_ANSWERED"]);
                $rowcounter++;
                $worksheet->writeString($rowcounter, 0, ilExcelUtils::_convert_text($this->lng->txt("users_skipped")), $format_bold);
                $worksheet->write($rowcounter, 1, $eval_data["USERS_SKIPPED"]);
                $rowcounter++;

                $worksheet->write($rowcounter, 0, $this->lng->txt("subtype"), $format_bold);
                switch ($this->getSubtype())
                {
                        case self::SUBTYPE_NON_RATIO:
                                $worksheet->write($rowcounter++, 1, ilExcelUtils::_convert_text($this->lng->txt("non_ratio")), $format_bold);
                                break;
                        case self::SUBTYPE_RATIO_NON_ABSOLUTE:
                                $worksheet->write($rowcounter++, 1, ilExcelUtils::_convert_text($this->lng->txt("ratio_non_absolute")), $format_bold);
                                break;
                        case self::SUBTYPE_RATIO_ABSOLUTE:
                                $worksheet->write($rowcounter++, 1, ilExcelUtils::_convert_text($this->lng->txt("ratio_absolute")), $format_bold);
                                break;
                }
                $worksheet->write($rowcounter, 0, ilExcelUtils::_convert_text($this->lng->txt("mode")), $format_bold);
                $worksheet->write($rowcounter++, 1, ilExcelUtils::_convert_text($eval_data["MODE"]));
                $worksheet->write($rowcounter, 0, ilExcelUtils::_convert_text($this->lng->txt("mode_text")), $format_bold);
                $worksheet->write($rowcounter++, 1, ilExcelUtils::_convert_text($eval_data["MODE"]));
                $worksheet->write($rowcounter, 0, ilExcelUtils::_convert_text($this->lng->txt("mode_nr_of_selections")), $format_bold);
                $worksheet->write($rowcounter++, 1, ilExcelUtils::_convert_text($eval_data["MODE_NR_OF_SELECTIONS"]));
                $worksheet->write($rowcounter, 0, ilExcelUtils::_convert_text($this->lng->txt("median")), $format_bold);
                $worksheet->write($rowcounter++, 1, ilExcelUtils::_convert_text($eval_data["MEDIAN"]));
                $worksheet->write($rowcounter, 0, ilExcelUtils::_convert_text($this->lng->txt("arithmetic_mean")), $format_bold);
                $worksheet->write($rowcounter++, 1, ilExcelUtils::_convert_text($eval_data["ARITHMETIC_MEAN"]));
                $worksheet->write($rowcounter, 0, ilExcelUtils::_convert_text($this->lng->txt("values")), $format_bold);
                $worksheet->write($rowcounter, 1, ilExcelUtils::_convert_text($this->lng->txt("value")), $format_title);
                $worksheet->write($rowcounter, 2, ilExcelUtils::_convert_text($this->lng->txt("category_nr_selected")), $format_title);
                $worksheet->write($rowcounter++, 3, ilExcelUtils::_convert_text($this->lng->txt("percentage_of_selections")), $format_title);
                $values = "";
                if (is_array($eval_data["values"]))
                {
                        foreach ($eval_data["values"] as $key => $value)
                        {
                                $worksheet->write($rowcounter, 1, ilExcelUtils::_convert_text($value["value"]));
                                $worksheet->write($rowcounter, 2, ilExcelUtils::_convert_text($value["selected"]));
                                $worksheet->write($rowcounter++, 3, ilExcelUtils::_convert_text($value["percentage"]), $format_percent);
                        }
                }
        }

        function addUserSpecificResultsData(&$a_array, &$resultset)
        {
                if (count($resultset["answers"][$this->getId()]))
                {
                        foreach ($resultset["answers"][$this->getId()] as $key => $answer)
                        {
                                array_push($a_array, $answer["value"]);
                        }
                }
                else
                {
                        array_push($a_array, $this->getSkippedValue());
                }
        }
        
        function &getUserAnswers($survey_id, $finished_ids)
        {
                global $ilDB;
                
                $answers = array();
                
                $sql = "SELECT svy_answer.* FROM svy_answer".
                        " JOIN svy_finished ON (svy_finished.finished_id = svy_answer.active_fi)".
                        " WHERE svy_answer.question_fi = ".$ilDB->quote($this->getId(), "integer").
                        " AND svy_finished.survey_fi = ".$ilDB->quote($survey_id, "integer");           
                if($finished_ids)
                {
                        $sql .= " AND ".$ilDB->in("svy_finished.finished_id", $finished_ids, "", "integer");
                }
                
                $result = $ilDB->query($sql);           
                while ($row = $ilDB->fetchAssoc($result))
                {
                        $answers[$row["active_fi"]] = $row["value"];
                }
                return $answers;
        }

        function importResponses($a_data)
        {
                foreach ($a_data as $id => $data)
                {
                        $this->setMinimum($data["min"]);
                        $this->setMaximum($data["max"]);
                }
        }

        function usableForPrecondition()
        {
                return TRUE;
        }

        function getAvailableRelations()
        {
                return array("<", "<=", "=", "<>", ">=", ">");
        }

        function outPreconditionSelectValue(&$template)
        {
                $template->setCurrentBlock("textfield");
                $template->setVariable("TEXTFIELD_VALUE", "");
                $template->parseCurrentBlock();
        }
        
        public function getPreconditionSelectValue($default = "", $title, $variable)
        {
                include_once "./Services/Form/classes/class.ilNumberInputGUI.php";
                $step3 = new ilNumberInputGUI($title, $variable);
                $step3->setValue($default);
                return $step3;
        }

        function getMinMaxText()
        {
                $min = $this->getMinimum();
                $max = $this->getMaximum();
                if (strlen($min) && strlen($max))
                {
                        return "(" . $min . " " . strtolower($this->lng->txt("to")) . " " . $max . ")";
                }
                else if (strlen($min))
                {
                        return "(&gt;= " . $min . ")";
                }
                else if (strlen($max))
                {
                        return "(&lt;= " . $max . ")";
                }
                else
                {
                        return "";
                }
        }
}
?>