Solved

contains 1 abstract method and must be declared abstract or implement remaining methods

Posted on 2014-03-24
2
2,060 Views
Last Modified: 2014-03-30
from
matt zandstra php objects patterns and practice

listing4.06.php
<?php
require_once( "listing04.03.php" );

abstract class ShopProductWriter {
    protected $products = array();

    public function addProduct( ShopProduct $shopProduct ) {
        $this->products[]=$shopProduct;
    }

    abstract public function write( );
}

class ErroredWriter extends ShopProductWriter{
}

$writer = new ErroredWriter();
?>

Open in new window


listing4.03.php
<?php
class ShopProduct {
    private $title;
    private $producerMainName;
    private $producerFirstName;
    protected $price;
    private $discount = 0; 
    private $id = 0;
    
    public function __construct(   $title, $firstName, 
                            $mainName, $price ) { 
        $this->title             = $title;
        $this->producerFirstName = $firstName;
        $this->producerMainName  = $mainName;
        $this->price             = $price;
    }

    public function setID( $id ) {
        $this->id = $id;
    }

    public function getProducerFirstName() {
        return $this->producerFirstName;
    }

    public function getProducerMainName() {
        return $this->producerMainName;
    }

    public function setDiscount( $num ) {
        $this->discount=$num;
    }

    public function getDiscount() {
        return $this->discount;
    }
    
    public function getTitle() {
        return $this->title;
    }

    public function getPrice() {
        return ($this->price - $this->discount);
    }

    public function getProducer() {
        return "{$this->producerFirstName}".
               " {$this->producerMainName}";
    }

    function getSummaryLine() {
        $base  = "$this->title ( $this->producerMainName, ";
        $base .= "$this->producerFirstName )"; 
        return $base;
    }

    public static function getInstance( $id, PDO $pdo ) {
        $query = "select * from products where id='$id'";
        $stmt = $pdo->prepare("select * from products where id=?");
        $result = $stmt->execute( array( $id ) );
        $row = $stmt->fetch( );
        if ( empty( $row ) ) { return null; }

        if ( $row['type'] == "book" ) {
            $product = new BookProduct( 
                                    $row['title'], 
                                    $row['firstname'], $row['mainname'], 
                                    $row['price'], $row['numpages'] ); 
        } else if ( $row['type'] == "cd" ) {
            $product = new CdProduct(
                                    $row['title'], 
                                    $row['firstname'], $row['mainname'], 
                                    $row['price'], $row['playlength'] ); 
        } else {
            $product = new ShopProduct(     
                                    $row['title'], 
                                    $row['firstname'], $row['mainname'], 
                                    $row['price'] ); 
        }
        $product->setId(            $row['id'] );
        $product->setDiscount(      $row['discount'] );
        return $product;
    }
}

class CdProduct extends ShopProduct {
    private $playLength = 0;

    public function __construct(   $title, $firstName, 
                            $mainName, $price, $playLength ) { 
        parent::__construct(    $title, $firstName, 
                                $mainName, $price );
        $this->playLength = $playLength;
    }

    public function getPlayLength() {
        return $this->playLength;
    }

    function getSummaryLine() {
        $base = parent::getSummaryLine();
        $base .= ": playing time - $this->playLength";
        return $base;
    }
 
}

class BookProduct extends ShopProduct {
    private $numPages = 0;

    public function __construct(   $title, $firstName, 
                            $mainName, $price, $numPages ) { 
        parent::__construct(    $title, $firstName, 
                                $mainName, $price );
        $this->numPages = $numPages;
    }

    public function getNumberOfPages() {
        return $this->numPages;
    }
   
    function getSummaryLine() {
        $base = parent::getSummaryLine();
        $base .= ": page count - $this->numPages";
        return $base;
    }

    public function getPrice() {
        return $this->price;
    }
}

require_once("generate_product_pdo.php");
$pdo = getPDO();
$obj = ShopProduct::getInstance( 1, $pdo );
print_r( $obj );
$obj = ShopProduct::getInstance( 2, $pdo );
print_r( $obj );
$obj = ShopProduct::getInstance( 3, $pdo );
print_r( $obj );
?>

Open in new window




Fatal error: Class ErroredWriter contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (ShopProductWriter::write) in C:\wamp\www\POPP-edition4-code\9781430260318_Chapter_04_Code\listing4.06.php on line 15
0
Comment
Question by:rgb192
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 110

Accepted Solution

by:
Ray Paseur earned 500 total points
ID: 39951855
If a child class extends an abstract parent class, the child must implement all of the abstract methods of the parent.  It's just a rule you have to follow.

The child may implement overriding methods for the non-abstract methods, but that's not very common.  

The parent has this:

abstract public function write( );

Therefore the child must provide the code for the write() method.
http://php.net/manual/en/language.oop5.abstract.php
0
 

Author Closing Comment

by:rgb192
ID: 39964960
child must contain write method

thanks.
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Part of the Global Positioning System A geocode (https://developers.google.com/maps/documentation/geocoding/) is the major subset of a GPS coordinate (http://en.wikipedia.org/wiki/Global_Positioning_System), the other parts being the altitude and t…
Many old projects have bad code, but the budget doesn't exist to rewrite the codebase. You can update this code to be safer by introducing contemporary input validation, sanitation, and safer database queries.
The viewer will learn how to create and use a small PHP class to apply a watermark to an image. This video shows the viewer the setup for the PHP watermark as well as important coding language. Continue to Part 2 to learn the core code used in creat…
This tutorial will teach you the core code needed to finalize the addition of a watermark to your image. The viewer will use a small PHP class to learn and create a watermark.

688 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question