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OOPS - concepts in php

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Object Oriented Programming (OOP) is the programming method that involves the use of the data , structure and organize classes of an application. The data structure becomes an objects that includes both functions and data. – PowerPoint PPT presentation

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Title: OOPS - concepts in php


1
OOPS -Concepts in PHP
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-110085
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(No Transcript)
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Topics to be covered
  • Interfaces
  • Abstract Classes
  • Static Methods And Properties
  • Accessor Methods
  • Determining A Object's Class
  • What is OOPS
  • Class Objects
  • Modifier
  • Constructor
  • Deconstructor
  • Class Constants
  • Inheritance In Php
  • Magic Function
  • Polymorphism

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What Is Oop ?
  • Object Oriented Programming (OOP) is the
    programming method that involves the use of the
    data , structure and organize classes of an
    application. The data structure becomes an
    objects that includes both functions and data. A
    relationship between one object and other object
    is created by the programmer

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Classes
  • A class is a programmer defined datatype which
    include local fuctions as well as local data.
  • Like a pattern or a blueprint a oops class has
    exact specifications.  The specification is the
    class' s contract.

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Object
An object is a like a container that contains
methods and properties which are require to make
a certain data types useful. An objects methods
are what it can do and its properties are what it
knows.
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Modifier
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Modifier
  • In object oriented programming, some Keywords
    are private and some are public in class. These
    keyword are known as modifier. These keywords
    help you to define how these variables and
    properties will be accessed by the user of this
    class.

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Modifier
  • Private Properties or methods declared as
    private are not allowed to be called from outside
    the class. However any method inside the same
    class can access them without a problem. In our
    Emailer class we have all these properties
    declared as private, so if we execute the
    following code we will find an error.

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Modifier
  • lt?
  • include_once("class.emailer.php")
  • emobject new Emailer("hasin_at_somewherein.net")
  • emobject-gtsubject "Hello world"
  • ?gt

The above code upon execution gives a fatal error
as shown below ltbgtFaprivate property
emailersubject in ltbgtC\OOP with
PHP5\Codes\ch1\class.emailer.phplt/bgt on line
ltbgt43lt/gtltbr /gt tal errorlt/bgt Cannot access That
means you can't access
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Modifier
  • Public Any property or method which is not
    explicitly declared as private or protected is a
    public method. You can access a public method
    from inside or outside the class.
  • Protected This is another modifier which has a
    special meaning in OOP. If any property or method
    is declared as protected, you can only access the
    method from its subclass. To see how a protected
    method or property actually works, we'll use the
    following example

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Modifier
  • To start, let's open class.emailer.php file (the
    Emailer class) and change the declaration of the
    sender variable. Make it as follows
  • protected sender
  • Now create another file name class.extendedemailer
    .php with the following code

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Modifier
  • lt?
  • class ExtendedEmailer extends emailer
  • function __construct()
  • public function setSender(sender)
  • this-gtsender sender
  • ?gt

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Constructor Destructor
  • Constructor is Acclimated to Initialize the
    Object.
  • Arguments can be taken by constructor.
  • A class name has same name as Constructor.
  • Memory allocation is done by Constructor.

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Constructor Destructor
  • The objects that are created in memory, are
    destroyed by the destructor.
  • Arguments can be taken by the destructor.
  • Overloading is possible in destructor.
  • It has same name as class name with tiled
    operator.

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Class Contants
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Class Constants
  • You can make constants in your PHP scripts
    utilizing the predefine keyword to define
    (constant name, constant value). At the same time
    to make constants in the class you need to
    utilize the const keyword. These constants really
    work like static variables, the main distinction
    is that they are read-only.

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Class Constants
  • lt?
  • class WordCounter
  • const ASC1 //you need not use sign before
    Constants
  • const DESC2
  • private words
  • function __construct(filename)
  • file_content file_get_contents(filename)
  • this-gtwords
  • (array_count_values(str_word_count(strtolower
  • (file_content),1)))

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Class Constants
  • public function count(order)
  • if (orderselfASC)
  • asort(this-gtwords)
  • else if(orderselfDESC)
  • arsort(this-gtwords)
  • foreach (this-gtwords as keygtval)
  • echo key ." ". val."ltbr/gt"
  • ?gt

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Inheritance
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Inheritance In Php
  • Inheritance is a well-known programming rule, and
    PHP makes utilization of this standard in its
    object model. This standard will influence the
    way numerous objects and classes identify with
    each other.
  • For illustration, when you extend a class, the
    subclass inherits each public and protected
    method from the guardian class. Unless a class
    overrides those techniques, they will hold their
    unique functionality

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Inheritance
23
Magic Functions
24
Magic Functions
  • There are some predefine function names which
    you cant use in your programme unless you have
    magic functionality relate with them. These
    functions are known as Magic Functions. Magic
    functions have special names which begine with
    two underscores.

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Magic Functions
  • _ _construct()
  • _ _deconstruct()
  • _ _call()
  • _ _callStatic()
  • _ _get()
  • _ _set()
  • _ _isset()
  • _ _unset()
  • __sleep()
  • __wakeup()
  • __tostring()
  • __invoke()
  • __ set_state()
  • __ clone()
  • __ debugInfo()

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Magic Functions
  • _ _construct()
  • Construct function is called when object is
    instantiated. Generally it is used in php 5 for
    creating constructor
  • _ _deconstruct()
  • It is the opposite of construct function. When
    object of a class is unset, this function is
    called.

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Magic Functions
  • _ _call()
  • When a class in a function is try to call an
    accessible or inaccessible function , this method
    is called.
  • _ _callStatic()
  • It is similar to __callStatic() with only one
    difference that is its triggered when you try to
    call an accessible or inaccessible function in
    static context.

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Magic Functions
  • _ _get()
  • This function is triggered when your object try
    call a variable of a class which is either
    unavailable or inaccessible.
  • _ _set()
  • This function is called when we try to change to
    value of a property which is unavailable or
    inaccessible.

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Polymorphism
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Polymorphism
  • The ability of a object, variable or function to
    appear in many form is known as polymorphism. It
    allows a developer to programme in general rather
    than programme in specific. There are two types
    of polymorphism.
  • compile time polymorphism
  • run-time polymorphism".

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Interfaces
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Interfaces
  • There are some specific set of variable and
    functions which can be called outside a class
    itself. These are known as interfaces. Interfaces
    are declared using interface keyword.
  • lt?
  • //interface.dbdriver.php
  • interface DBDriver
  • public function connect()
  • public function execute(sql)
  • ?gt

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Abstract Classes
34
Abstract Classes
  • A class which is declared using abstract keyword
    is known as abstract class. An abstract class is
    not implemented just declared only (followed by
    semicolon without braces)
  • lt?
  • //abstract.reportgenerator.php
  • abstract class ReportGenerator
  • public function generateReport(resultArray)
  • //write code to process the multidimensional
    result array and
  • //generate HTML Report
  • ?

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Static Method And Properties
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Static Methods Properties
  • In object oriented programming, static keyword is
    very crucial. Static properties and method acts
    as a significant element in design pattern and
    application design. To access any method or
    attribute in a class you must create an instance
    (i.e. using new keyword, like object new
    emailer()), otherwise you can't access them. But
    there is a difference for static methods and
    properties. You can access a static method or
    property directly without creating any instance
    of that class. A static member is like a global
    member for that class and all instances of that
    class

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Static Methods Properties
  • lt?
  • //class.dbmanager.php
  • class DBManager
  • public static function getMySQLDriver()
  • //instantiate a new MySQL Driver object and
    return
  • public static function getPostgreSQLDriver()

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Static Methods Properties
  • //instantiate a new PostgreSQL Driver object and
    return
  • public static function getSQLiteDriver()
  • //instantiate a new MySQL Driver object and
    return
  • ?gt

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Accessor Method
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Accessor Method
  • Accessor methods are simply methods that are
    solely devoted to get and set the value of any
    class properties. It's a good practice to access
    class properties using accessor methods instead
    of directly setting or getting their value.
    Though accessor methods are the same as other
    methods, there are some conventions writing them.
    There are two types of accessor methods. One is
    called getter, whose purpose is returning value
    of any class property. The other is setter that
    sets a value into a class property.

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Accessor Method
  • lt?
  • class Student
  • private name
  • private roll
  • More free ebooks http//fast-file.blogspot.com
  • Chapter 2
  • 39
  • public function setName(name)
  • this-gtname name

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Accessor Method
  • public function setRoll(roll)
  • this-gtroll roll
  • public function getName()
  • return this-gtname
  • public function getRoll()
  • return this-gtroll
  • ?gt

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Determining A Object's Class
  • public function setRoll(roll)
  • this-gtroll roll
  • public function getName()
  • return this-gtname
  • public function getRoll()
  • return this-gtroll
  • ?gt

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