PHP collection class

August 9, 2003 on 2:05 pm | In PHP |

Below is a simple collection class that works approximately like Java collection classes.

The usage should be fairly obvious, but you may also refer to the sample code at the end.

Collection.php

 1 <?php
 2 class Collection {
 3     var $elements = array();
 4     var $counter = 0;
 5     var $pointer = 0;
 6
 7     function Collection() {
 8
 9     }
10
11     function add($element) {
12         $this->elements[$this->counter] = $element;
13         $this->counter++;
14         $this->pointer++;
15     }
16
17     function remove($element) {
18         $found = null;
19         for ($i = 0; $i < count($this->elements); $i++) {
20             if ($this->elements[$i] == $element) {
21                 $found = $i;
22             }
23         }
24         if ($found != null) {
25             array_splice($this->elements, $found, 1);
26             $this->counter--;
27             $this->pointer--;
28         }
29     }
30
31     function contains($element) {
32         for ($i = 0; $i < count($this->elements); $i++) {
33             if ($this->elements[$i] == $element) {
34                 return true;
35             }
36         }
37         return false;
38     }
39
40     function hasNext() {
41         return $this->pointer < $this->counter;
42     }
43
44     function hasPrevious() {
45         return $this->pointer > 0;
46     }
47
48     function next() {
49         return $this->elements[$this->pointer++];
50     }
51
52     function first() {
53         $this->pointer = 0;
54         return $this->elements[$this->pointer];
55     }
56
57     function last() {
58         $this->pointer = $this->counter;
59         return $this->elements[$this->pointer];
60     }
61
62     function previous() {
63         return $this->elements[--$this->pointer];
64     }
65
66     function count() {
67         return count($this->elements);
68     }
69 }
70
71 ?>

Sample

 1 <?php
 2
 3 require_once "Collection.php";
 4
 5 $collection = new Collection();
 6
 7 for ($i = 0; $i < 10; $i++) {
 8     $element = "Element $i";
 9     $collection->add($element);
10 }
11
12 $collection->first();
13 while ($collection->hasNext() ) {
14     $element = $collection->next();
15     echo $element . "n";
16 }
17
18 echo "n";
19
20 $collection->previous();
21 $collection->previous();
22 $collection->remove("Element 7");
23
24 $collection->last();
25 while ($collection->hasPrevious() ) {
26     $element = $collection->previous();
27     echo $element . "n";
28 }
29
30 ?>

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