Drupal investigation

EventArgs.php 2.4KB

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  1. <?php
  2. /*
  3. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  4. * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  5. * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  6. * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  7. * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  8. * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  9. * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  10. * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  11. * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  12. * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  13. * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  14. *
  15. * This software consists of voluntary contributions made by many individuals
  16. * and is licensed under the MIT license. For more information, see
  17. * <http://www.doctrine-project.org>.
  18. */
  19. namespace Doctrine\Common;
  20. /**
  21. * EventArgs is the base class for classes containing event data.
  22. *
  23. * This class contains no event data. It is used by events that do not pass state
  24. * information to an event handler when an event is raised. The single empty EventArgs
  25. * instance can be obtained through {@link getEmptyInstance}.
  26. *
  27. * @link www.doctrine-project.org
  28. * @since 2.0
  29. * @author Guilherme Blanco <guilhermeblanco@hotmail.com>
  30. * @author Jonathan Wage <jonwage@gmail.com>
  31. * @author Roman Borschel <roman@code-factory.org>
  32. */
  33. class EventArgs
  34. {
  35. /**
  36. * Single instance of EventArgs.
  37. *
  38. * @var EventArgs
  39. */
  40. private static $_emptyEventArgsInstance;
  41. /**
  42. * Gets the single, empty and immutable EventArgs instance.
  43. *
  44. * This instance will be used when events are dispatched without any parameter,
  45. * like this: EventManager::dispatchEvent('eventname');
  46. *
  47. * The benefit from this is that only one empty instance is instantiated and shared
  48. * (otherwise there would be instances for every dispatched in the abovementioned form).
  49. *
  50. * @see EventManager::dispatchEvent
  51. *
  52. * @link http://msdn.microsoft.com/en-us/library/system.eventargs.aspx
  53. *
  54. * @return EventArgs
  55. */
  56. public static function getEmptyInstance()
  57. {
  58. if ( ! self::$_emptyEventArgsInstance) {
  59. self::$_emptyEventArgsInstance = new EventArgs;
  60. }
  61. return self::$_emptyEventArgsInstance;
  62. }
  63. }