Full collections in PHP

Not so long ago, when developing my project, an idea arose to implement full-fledged collections for storing objects of the same type, which, for convenience, resemble List <Type> in C #.
The idea is that collections containing objects of different types are different in themselves, and do not have, say, one unified type Collection . In other words, a collection of User objects is not the same as a collection of Book objects. Naturally, the first thought was to create different classes for collections ( UserCollection , BookCollection , ...). But the data approach does not provide the necessary flexibility, plus everything, you need to spend time declaring each such class.
After a bit of thinking, I implemented the dynamic creation of collection classes. It looks like this: the user creates a collection of objects of type Book, and the desired type BookCollection is created (that is, declared) automatically.

What I got in the end:

- Full TypeHinting created types of collections.
- Strong typing collections.
- It is possible to access the collection as an array as in C # (by implementing the ArrayAccess interface)
- Full iteration of the collection (possibility of use in any cycles).

Implementation

Collection factory

/** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .

1. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
2. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
3. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
4. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
5. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
6. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
8. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
9. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
10. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
11. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
12. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
13. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
14. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
15. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
16. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
17. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
18. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
19. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
20. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
22. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
23. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
24. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
25. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
26. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
27. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
28. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
29. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
30. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
31. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
32. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .
33. /** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .

/** * * * @author [x26]VOLAND */ abstract class CollectionFactory { /** * . * * @param string $type * @return mixed */ public static function create($type) { $ class = $type . 'Collection' ; self::__create_class($ class ); $obj = new $ class ($type); return $obj; } /** * $class * * @param string $class * @return void */ private static function __create_class($ class ) { if ( ! class_exists($ class )) { eval( 'class ' . $ class . ' extends Collection { }' ); } } } * This source code was highlighted with Source Code Highlighter .

')

Collection class (describes behavior)

1. / **
2. * Collection class
3. * Basic universal type, based on which collections will be created.
4. *
5. * @author [x26] VOLAND
6. * /
7. abstract class Collection implements IteratorAggregate, ArrayAccess, Countable {
9. / **
10. * The type of items stored in this collection.
11. * @var string
12. * /
13. private $ __ type;
15. / **
16. * Object storage
17. * @var array
18. * /
19. private $ __ collection = array ();
21. // ------------------------------------------------ --------------------
23. / **
24. * Constructor.
25. * Sets the type of elements that will be stored in this collection.
26. *
27. * @param string $ type Element type
28. * @return void
29. * /
30. public function __construct ($ type) {
31. $ this -> __ type = $ type;
32. }
34. // ------------------------------------------------ --------------------
36. / **
37. * Checks the type of object.
38. * Prevents the addition to the collection of objects of someone else’s type.
39. *
40. * @param object $ object Object to check
41. * @return void
42. * @throws Exception
43. * /
44. private function __check_type (& $ object ) {
45. if (get_class ($ object )! = $ this -> __ type) {
46. throw new Exception ( 'Object of type' ' . get_class ($ object )
47. . '`cannot be added to the collection of objects of type' ' . $ this -> __ type. '`' );
48. }
49. }
51. // ------------------------------------------------ --------------------
53. / **
54. * Adds the objects passed in the arguments to the collection.
55. *
56. * @param object (s) Objects
57. * @return mixed collection
58. * /
59. public function add ()
60. {
61. $ args = func_get_args ();
62. foreach ($ args as $ object ) {
63. $ this -> __ check_type ($ object );
64. $ this -> __ collection [] = $ object ;
65. }
66. return $ this ;
67. }
69. // ------------------------------------------------ --------------------
71. / **
72. * Removes from the collection the objects passed in the arguments.
73. *
74. * @param object (s) Objects
75. * @return mixed collection
76. * /
77. public function remove ()
78. {
79. $ args = func_get_args ();
80. foreach ($ args as $ object ) {
81. unset ($ this -> __ collection [array_search ($ object , $ this -> __ collection)]);
82. }
83. return $ this ;
84. }
86. // ------------------------------------------------ --------------------
88. / **
89. * Clears the collection.
90. *
91. * @return mixed collection
92. * /
93. public function clear () {
94. $ this -> __ collection = array ();
95. return $ this ;
96. }
98. // ------------------------------------------------ --------------------
100. / **
101. * Determines if the collection is empty.
102. *
103. * @return bool
104. * /
105. public function isEmpty () {
106. return empty ($ this -> __ collection);
107. }
109. // ------------------------------------------------ --------------------
111. / **
112. * IteratorAggregate interface implementation
113. * /
115. / **
116. * Returns an iterator object.
117. *
118. * @return CollectionIterator
119. * /
120. public function getIterator () {
121. return new CollectionIterator ($ this -> __ collection);
122. }
124. // ------------------------------------------------ --------------------
127. / **
128. * Implementation of the ArrayAccess interface.
129. * /
131. / **
132. * Sets an element of collection at the offset
133. *
134. * @param ineter $ offset Offset
135. * @param mixed $ offset Object
136. * @return void
137. * /
138. public function offsetSet ($ offset, $ object ) {
139. $ this -> __ check_type ($ object );
140. if ($ offset === NULL) {
141. $ offset = max (array_keys ($ this -> __ collection)) + 1;
142. }
143. $ this -> __ collection [$ offset] = $ object ;
144. }
146. // ------------------------------------------------ --------------------
148. / **
149. * Find out if an item exists with a given key.
150. *
151. * @param integer $ offset Key
152. * @return bool
153. * /
154. public function offsetExists ($ offset) {
155. return isset ($ this -> __ collection [$ offset]);
156. }
158. // ------------------------------------------------ --------------------
160. / **
161. * Removes the item referenced by the $ offset key.
162. *
163. * @param integer $ offset Key
164. * @return void
165. * /
166. public function offsetUnset ($ offset) {
167. unset ($ this -> __ collection [$ offset]);
168. }
170. // ------------------------------------------------ --------------------
172. / **
173. * Returns an item by key.
174. *
175. * @param integer $ offset Key
176. * @return mixed
177. * /
178. public function offsetGet ($ offset) {
179. if (isset ($ this -> __ collection [$ offset]) === FALSE) {
180. return NULL;
181. }
182. return $ this -> __ collection [$ offset];
183. }
185. // ------------------------------------------------ --------------------
188. / **
189. * Implementing the Countable Interface
190. * /
192. / **
193. * Returns the number of items in the collection.
194. *
195. * @return integer
196. * /
197. public function count () {
198. return sizeof ($ this -> __ collection);
199. }
200. }

* This source code was highlighted with Source Code Highlighter .

Examples of using

1. <? php
3. class BookStore {
4. function addBooks (BookCollection $ books) {
5. // implementation
6. }
8. function addMagazines (MagazineCollection $ magazines) {
9. // implementation
10. }
12. function addGoods (Collection $ goods) {
13. // If collection type is not important,
14. // you can specify the base type of collection
15. }
16. }
17. class Book {
18. var $ id;
19. function Book ($ id) {
20. $ this -> id = $ id;
21. }
22. }
25. class Magazine {
26. var $ id;
27. function Magazine ($ id) {
28. $ this -> id = $ id;
29. }
30. }
31. // Create a collection
32. $ books = CollectionFactory :: create ( 'Book' );
34. echo get_class ($ books); // BookCollection
36. // Add objects to the collection:
37. $ books-> add ( new Book (1), new Book (2));
38. $ books-> add ( new Book (3)) -> add ( new Book (2));
39. $ books [] = new Book (5);
41. echo count ($ books); // five
43. ...
45. foreach ($ books as $ book) {
46. echo $ book-> id;
47. } // 12345
49. ...
51. $ books-> add ( new Magazine (1)); // Error (wrong type)
53. ...
55. $ magazines = CollectionFactory :: create ( 'Magazine' );
56. $ magazines-> add ( new Magazine (1));
58. ...
60. $ bookStore = new BookStore ();
62. $ bookStore-> addBooks ($ books); // Everything is good
64. $ bookStore-> addBooks ($ magazines); // Error (wrong type)
65. $ bookStore-> addMagazines ($ magazines); // Everything is good
67. $ bookStore-> addGoods ($ books); // Everything is good
68. $ bookStore-> addGoods ($ magazines); // Everything is good
70. ?>

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