php - why does assigning a reference to a static class variable break inheritance of such variable? -


i don't understand why, in code below, $my_foo , $my_bar correctly inherited child class, if change $my_foo assigning reference $my_var, child class still sees original value..

  <?php     class foo     {         public static $my_foo = 'foo';         public static $my_bar = 'bar';          public static function break_inheritance() {             self::$my_bar = &self::$my_foo;         }          public static function foo_print_vars() {             print self::$my_foo." ";             print self::$my_bar."\n";         }     }      class bar extends foo     {         public static function bar_print_vars() {             print self::$my_foo." ";             print self::$my_bar."\n";         }     }       bar::bar_print_vars(); // outputs foo bar     foo::break_inheritance();      foo::foo_print_vars(); // outputs foo foo     bar::bar_print_vars(); // outputs foo bar

edit: similar question: do extended classes inherit static var values (php)? mine more focused on inheritance , references.

edit2: please note point of question not late static binding, it's why, since $my_foo , $my_bar inherited, changing them in foo doesn't affect them when accessed in bar. , only happens references. in fact if change:

 public static function break_inheritance() {             self::$my_bar = self::$my_foo; // removed reference in assignment         }

the behavior totally changes , last bar::bar_print_vars(); // outputs foo foo

foo different class bar. try calling bar::break_inheritance(); , see happens.


Comments

Post a Comment

Popular posts from this blog

java - Spring Data JPA: Why findOne(id) executing delete query internally? -

i have 1 application using @manytomany annotation link 2 different entities 1 parent entity. not sure if have implemented properly. when execute .findone() on parent entity's repository find it, @ first fetch data along executing delete queries internally delete record mapping table (a table jpa creates after adding @manytomany annotation.). following generated sql queries , code snippet: java class @entity @table(name = "inventory") public class inventory { @id long id; // many other properties @manytomany(fetch=fetchtype.lazy) private list<stream> streams; @manytomany(fetch=fetchtype.lazy) private list<subject> subjects; } there no other annotation i've put in stream , subject entity class link inventory class. when run app, create following tables: inventory stream subject inventory_stream inventory_subject (inventory_stream , inventory_subject, 2 tables created automatically, don't k...
Read more

python - Mongodb How to add addtional information when aggregating? -

i beginner , wrote line pipeline works, wanna add other information output, screen name , or number of tweets.i tried add under $group gave me syntax error everytime here pipeline: def make_pipeline(): # complete aggregation pipeline pipeline = [ { '$match': { "user.statuses_count": {"$gt":99 }, "user.time_zone": "brasilia" } }, { "$group": { "_id": "$user.id", "followers": { "$max": "$user.followers_count" } } }, { "$sort": { "followers": -1 } }, { "$limit" : 1 } ]; i using on example : { "_id" : objectid("5304e2e3cc9e684aa98bef97"), "text" : "first week of school on :p", "in_reply_to_status_id" : null, "retweet_count" : null, ...
Read more

java - Incorrect order of records in M-M relationship in hibernate -

Image
i have 4 records in bridge table in mysql database. using @manytomany in hibernate, accurate order of employees incorrect incorrect of projects. following required material figure out doing mistake. this source. @entity @table(name="project") public class projectbean { @id @generatedvalue @column(name="project_id") private int projectid; @column(name="title") private string projecttitle; @manytomany(mappedby="projects") private collection<employeebean> employees; public projectbean() { employees = new arraylist<employeebean>(); } //getters & setters } @entity @table(name="employee") public class employeebean { @id @generatedvalue @column(name="employee_id") private int employee_id; @column(name="first_name") private string ...
Read more