git.m6w6.name Git - mdref/mdref-pq/blob - pq/Converter.md

   1 # interface pq\Converter
   2
   3 Interface for type conversions.
   4
   5 ## Example:
   6
   7         <?php
   8
   9         /**
  10          * Naive geometric point
  11          */
  12         class Point {
  13                 public $x;
  14                 public $y;
  15                 function __construct($x, $y) {
  16                         $this->x = $x;
  17                         $this->y = $y;
  18                 }
  19         }
  20
  21         /**
  22          * A simple Box
  23          */
  24         class Box {
  25                 public $p1;
  26                 public $p2;
  27                 function __construct(Point $p1, Point $p2) {
  28                         $this->p1 = $p1;
  29                         $this->p2 = $p2;
  30                 }
  31         }
  32
  33         /**
  34          * Our converter handles only objects of type box
  35          */
  36         class BoxConverter implements pq\Converter {
  37                 private $oid;
  38                 function __construct(pq\Types $types) {
  39                         $this->oid = $types["box"]->oid;
  40                 }
  41
  42                 /**
  43                  * @return array
  44                  * @see pq\Converter::convertTypes()
  45                  */
  46                 function convertTypes() {
  47                         return [$this->oid];
  48                 }
  49
  50                 /**
  51                  * @return string
  52                  * @param $box Box
  53                  * @see pq\Converter::convertToString()
  54                  */
  55                 function convertToString($box, $type = NULL) {
  56                         return sprintf("(%F,%F),(%F,%F)",
  57                                 $box->p1->x, $box->p1->y,
  58                                 $box->p2->x, $box->p2->y
  59                         );
  60                 }
  61
  62                 /**
  63                  * @return Box
  64                  * @param string $data
  65                  * @see pq\Converter::convertFromString()
  66                  */
  67                 function convertFromString($data, $type = NULL) {
  68                         list($p1x, $p1y, $p2x, $p2y) = sscanf($data, "(%f,%f),(%f,%f)");
  69                         return new Box(new Point($p1x, $p1y), new Point($p2x, $p2y));
  70                 }
  71         }
  72
  73         $conn  = new pq\Connection;
  74         $types = new pq\Types($conn);
  75         $conv  = new BoxConverter($types);
  76         $inbox = new Box(new Point(1.1, 2.2), new Point(3.3, 4.4));
  77
  78         $conn->setConverter($conv);
  79         $result = $conn->execParams("SELECT \$1", [$inbox], [$types["box"]->oid]);
  80         $result->fetchCol($outbox);
  81
  82         var_dump($outbox);
  83
  84         ?>
  85
  86 Yields:
  87
  88         object(Box)#163 (2) {
  89           ["p1"]=>
  90           object(Point)#164 (2) {
  91                 ["x"]=>
  92                 float(3.3)
  93                 ["y"]=>
  94                 float(4.4)
  95           }
  96           ["p2"]=>
  97           object(Point)#165 (2) {
  98                 ["x"]=>
  99                 float(1.1)
 100                 ["y"]=>
 101                 float(2.2)
 102           }
 103         }