GoF Strategyパターン

Strategy.php

<?php
abstract class ReadItemDataStrategy{
    private $filename;
    public function __construct($filename){
        $this->filename = $filename;
    }
    
    public function getData(){
        if (!is_readable($this->getFilename())){
            throw new Exception('file [' . $this->getFilename() . '] is not readable !');
        }
        
        return $this->readData($this->getFilename());
    }
    
    public function getFilename(){
        return $this->filename;
    }
    
    protected abstract function readData($filename);
}

class ReadTabSeparatedDataStrategy extends ReadItemDataStrategy{
    protected function readData($filename){
        $fp = fopen($filename, 'r');
        $dummy = fgets($fp, 4096);
        
        $return_value = array();
        while ($buffer = fgets($fp, 4096)){
            $buffer = rtrim($buffer);
            list($item_code, $item_name, $price, $release_date) = explode(",", $buffer);
            $obj = new stdClass();
            $obj->item_name = $item_name;
            $obj->item_code = $item_code;
            $obj->price     = $price;
            
            list($year, $mon, $day) = explode('/', $release_date);
            $obj->release_date = mktime(0,0,0,
                                        $mon,
                                        $day,
                                        $year);
            $return_value[] = $obj;
        }
        
        fclose($fp);
        return $return_value;
    }
}

class ReadFixedLengthDataStrategy extends ReadItemDataStrategy{
    protected function readData($filename){
        $fp = fopen($filename, 'r');
        $dummy = fgets($fp, 4096);
        
        $return_value = array();
        while ($buffer = fgets($fp, 4096)){
            $buffer = rtrim($buffer);
            $item_name = trim(substr($buffer, 0, 20));
            $item_code = trim(substr($buffer, 20, 10));
            $price     = (int)substr($buffer, 30, 8);
            $release_date = substr($buffer, 38);
            
            $obj = new stdClass();
            $obj->item_name = $item_name;
            $obj->item_code = $item_code;
            $obj->price     = $price;
            
            $obj->release_date = mktime(0,0,0,
                                        substr($release_date, 4, 2),
                                        substr($release_date, 6, 2),
                                        substr($release_date, 0, 4));
            $return_value[] = $obj;
        }
        
        fclose($fp);
        return $return_value;
    }
}

class ItemDataContext{
    private $strategy;
    public function __construct(ReadItemDataStrategy $strategy){
        $this->strategy = $strategy;
    }
    
    public function getItemData(){
        return $this->strategy->getData();
    }
}

function dumpData($data){
    echo '<dl>';
    foreach($data as $object){
        echo '<dt>' . $object->item_name . '</dt>';
        echo '<dd>商品番号：' . $object->item_code . '</dd>';
        echo '<dd>\\' . number_format($object->price) . '-</dd>';
        echo '<dd>' . date('y/m/d', $object->release_date) . '発売</dd>';
    }
    echo '<dl>';
}

$strategy1 = new ReadTabSeparatedDataStrategy('fixed_length_data.txt');
$context1 = new ItemDataContext($strategy1);
dumpData($context1->getItemData());