PHP 객체 지향의 일부 메서드 및 함수 응용 프로그램에 대한 코드

<?php
class ConstructTest {
    private $arg1;
    private $arg2;
 
    public function __construct($arg1, $arg2) {
        $this->arg1 = $arg1;
        $this->arg2 = $arg2;
        print "__construct is called...\n";
    }
    public function printAttributes() {
        print &#39;$arg1 = &#39;.$this->arg1.&#39; $arg2 = &#39;.$this->arg2."\n";
    }
}
$testObject = new ConstructTest("arg1","arg2");
$testObject->printAttributes();

Stephens-Air:Desktop$ php Test.php 
__construct is called...
$arg1 = arg1 $arg2 = arg2

<?php
class BaseClass {
    protected $arg1;
    protected $arg2;
 
    function __construct($arg1, $arg2) {
        $this->arg1 = $arg1;
        $this->arg2 = $arg2;
        print "__construct is called...\n";
    }
    function getAttributes() {
        return &#39;$arg1 = &#39;.$this->arg1.&#39; $arg2 = &#39;.$this->arg2;
    }
}
 
class SubClass extends BaseClass {
    protected $arg3;
 
    function __construct($baseArg1, $baseArg2, $subArg3) {
        parent::__construct($baseArg1, $baseArg2);
        $this->arg3 = $subArg3;
    }
    function getAttributes() {
        return parent::getAttributes().&#39; $arg3 = &#39;.$this->arg3;
    }
}
$testObject = new SubClass("arg1","arg2","arg3");
print $testObject->getAttributes()."\n";

Stephens-Air:Desktop$ php Test.php 
__construct is called...
$arg1 = arg1 $arg2 = arg2 $arg3 = arg3

<?php
class StaticExample {
    static public $arg1 = "Hello, This is static field.\n";
    static public function sayHello() {
        print self::$arg1;
    }
}
 
print StaticExample::$arg1;
StaticExample::sayHello();

Stephens-Air:Desktop$ php Test.php 
Hello, This is static field.
Hello, This is static field.

<?php
abstract class Base {
    public static function getInstance() {
        //这里的new static()实例化的是调用该静态方法的当前类。
        return new static();
    }
    abstract public function printSelf();
}
 
class SubA extends Base {
    public function printSelf() {
        print "This is SubA::printSelf.\n";
    }
}
 
class SubB extends Base {
    public function printSelf() {
        print "This is SubB::printSelf.\n";
    }
}
 
SubA::getInstance()->printSelf();
SubB::getInstance()->printSelf();

Stephens-Air:Desktop$ php Test.php 
This is SubA::printSelf.
This is SubB::printSelf.

<?php
abstract class Base {
    private $ownedGroup;
    public function __construct() {
        //这里的static和上面的例子一样，表示当前调用该方法的实际类。
        //需要另外说明的是，这里的getGroup方法即便不是静态方法，也会得到相同的结果。然而倘若
        //getGroup真的只是普通类方法，那么这里还是建议使用$this。
        $this->ownedGroup = static::getGroup();
    }
    public function printGroup() {
        print "My Group is ".$this->ownedGroup."\n";
    }
    public static function getInstance() {
        return new static();
    }
    public static function getGroup() {
        return "default";
    }
}
 
class SubA extends Base {
}
 
class SubB extends Base {
    public static function getGroup() {
        return "SubB";
    }
}
 
SubA::getInstance()->printGroup();
SubB::getInstance()->printGroup();

Stephens-Air:Desktop$ php Test.php 
My Group is default
My Group is SubB

<?php
class TestClass {
    function __destruct() {
        print "TestClass destructor is called.\n";
    }
}
 
$testObj = new TestClass();
unset($testObj);
print "Application will exit.\n";

Stephens-Air:Desktop$ php Test.php 
TestClass destructor is called.
Application will exit.

<?php
class InnerClass {
    public $id = 10;
    public function printSelf() {
        print &#39;$id = &#39;.$this->id."\n";
    }
}
 
class OuterClass {
    public $innerClass;
    public function __construct() {
        $this->innerClass = new InnerClass();
    }
    public function __clone() {
        $this->innerClass = clone $this->innerClass;
        print "__clone is called.\n";
    }
}
 
$outerA = new OuterClass();
print "Before calling to clone.\n";
$outerB = clone $outerA;
print "After calling to clone.\n";
$outerA->innerClass->id = 20;
print "In outerA: ";
$outerA->innerClass->printSelf();
print "In outerB: ";
$outerB->innerClass->printSelf();

Stephens-Air:Desktop$ php Test.php 
Before calling to clone.
__clone is called.
After calling to clone.
In outerA: $id = 20
In outerB: $id = 10

<?php
class TestClass {
    const AVAILABLE = 0;
}
print "TestClass::AVAILABLE = ".TestClass::AVAILABLE."\n";

0Stephens-Air:Desktop$ php Test.php 
TestClass::AVAILABLE = 0