downloads | documentation | faq | getting help | mailing lists | licenses | wiki | reporting bugs | php.net sites | links | conferences | my php.net

search for in the

命名空间概述> <对象序列化
[edit] Last updated: Fri, 22 Jul 2011

view this page in



add a note add a note User Contributed Notes 命名空间
Anonymous 25-May-2011 06:06
The keyword 'use' has two different applications, but the reserved word table links to here.

It can apply to namespace constucts:

file1:
<?php namespace foo;
  class
Cat {
    static function
says() {echo 'meoow';}  } ?>

file2:
<?php namespace bar;
  class
Dog {
    static function
says() {echo 'ruff';}  } ?>

file3:
<?php namespace animate;
  class
Animal {
    static function
breathes() {echo 'air';}  } ?>

file4:
<?php namespace fub;
  include
'file1.php';
  include
'file2.php';
  include
'file3.php';
  use
foo as feline;
  use
bar as canine;
  use
animate;
  echo \
feline\Cat::says(), "<br />\n";
  echo \
canine\Dog::says(), "<br />\n";
  echo \
animate\Animal::breathes(), "<br />\n"?>

Note that
felineCat::says()
should be
\feline\Cat::says()
(and similar for the others)
but this comment form deletes the backslash (why???)

The 'use' keyword also applies to closure constructs:

<?php function getTotal($products_costs, $tax)
    {
       
$total = 0.00;
       
       
$callback =
            function (
$pricePerItem) use ($tax, &$total)
            {
               
               
$total += $pricePerItem * ($tax + 1.0);
            };
       
       
array_walk($products_costs, $callback);
        return
round($total, 2);
    }
?>
netmosfera at gmail dot com 22-Apr-2011 06:09
for example, if you use a lot of .php files (once per class) you need to know that require() a lot of files will slow down consistently the page load

so you can use namespaces + autoload to implement package-specific initialization handlers

i used this to put an entire package (lot of classes) in one php file

!!! please note you can't use this as-is but you need to adapt it to your project

the file __init.php is placed inside every namespace/folder you want to load
there you can startup your namespace, check for environment, debugging, or as i do, you can merge all the package in one php file and require it to load other classes too.

<?php

class Loader
{
   
// here we store the already-initialized namespaces
   
private static $loadedNamespaces = array();
 
    static function
loadClass($className)
    {
       
// we assume the class AAA\BBB\CCC is placed in /AAA/BBB/CCC.php
       
$className = str_replace(array('/', '\\'), \DIRECTORY_SEPARATOR, $className);
      
       
// we get the namespace parts
       
$namespaces = explode(\DIRECTORY_SEPARATOR, $className);
        unset(
$namespaces[sizeof($namespaces)-1]); // the last item is the classname
      
        // now we loops over namespaces
       
$current=""; foreach($namespaces as $namepart)
        {
           
// we chain $namepart to parent namespace string
           
$current.='\\' . $namepart;
           
// skip if the namespace is already initialized
           
if(in_array($current, self::$loadedNamespaces)) continue;
           
// wow, we got a namespace to load, so:
           
$fnload = $current . \DIRECTORY_SEPARATOR . "__init.php";
            if(
file_exists($fnload)) require($fnload);
           
// then we flag the namespace as already-loaded
           
self::$loadedNamespaces[] = $current;
        }

       
// we build the filename to require
       
$load = $className . ".php";
       
// check for file existence
       
!file_exists($load) ?: require($load);
       
// return true if class is loaded
       
return class_exists($className, false);
    }
    static function
register()
    {
       
spl_autoload_register("Loader::loadClass");
    }
    static function
unregister()
    {
       
spl_autoload_unregister("Loader::loadClass");
    }
}

Loader::register();

?>

 
show source | credits | sitemap | contact | advertising | mirror sites