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Customizing object construction

From: Object-Oriented Programming with PHP

Video: Customizing object construction

Starting in PHP5, developers could use a magic method for initializing new objects. Before they were used. It's called _ construct (), and this magic method is Optional. It's flexible enough that even can be empty, which is the same as not having a magic construct method at all. If you don't need to initialize an object, don't use it, as it's just wasted code. Developers shouldn't be paid by the line. In the Address class, I'm going to use the magic construct method to set the creation time. Let's open the Address class. Add the following after the properties, before the Magic _get and _set methods.

Customizing object construction

Starting in PHP5, developers could use a magic method for initializing new objects. Before they were used. It's called _ construct (), and this magic method is Optional. It's flexible enough that even can be empty, which is the same as not having a magic construct method at all. If you don't need to initialize an object, don't use it, as it's just wasted code. Developers shouldn't be paid by the line. In the Address class, I'm going to use the magic construct method to set the creation time. Let's open the Address class. Add the following after the properties, before the Magic _get and _set methods.

function __construct. In its current form, this will have no functional effect, neither positive nor negative. If you are declaring a class, and have no need to customize the constructor, leave it out. In the case of your address, you want to set the time created upon initialization. In between the brackets, add the following line: this ->time_created = time(). Save the address class, then rerun the demo.

In the debug, you'll see that time created is now set. This technically works, but it's impractical to specify each property name when populating an object. Fortunately, I can pass arguments to the _construct() magic method, which I can then use to optionally populate the object. Let's go back to the Address class. data = array. And some documentation. Optional array of property names and values.

Next, add a sanity check by ensuring that the argument is really an array. If not, trigger an error and fail. Ensure that the Address can be populated. If not, array trigger_error. Unable to construct address with a get_class$name.

If there is data in array, if there is at least one value, populate the Address with it. Iterate through the array. Later, you will want to be able to set the time created and time updated from an existing record. So, include logic for these protected properties that will allow them to be sent. Special case for protected properties, if in_array name, array time_created, and time_updated, $ name start with an underscore (_).

Finally, set the property. The existing Magic _set() method will trigger an error if you attempt to set an invalid property. $this->name = $value. You can now create a new address object with an array of properties and values. Save the Address class, then open the demo. Start with a title. echo h2 Testing Address __construct with an array. Next, create a new address object, but this time with an array as a property.

$address_2 is a new Address, which will populate with an array. street_address_1 is 123 Phony Ave. The city_name is Villageland, the subdivision_name is Region, postal_code is 67890, and the country_name is Canada.

Finally, display the result. echo $address_ 2 display. Save and test in your browser. You have laid the groundwork that will allow for easy object population from a database record that has been returned as an array. Next, you can simplify address displaying by defining how the object is rendered as a string.

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This video is part of

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Object-Oriented Programming with PHP

37 video lessons · 17796 viewers

Jon Peck
Author

 
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  1. 4m 10s
    1. Welcome
      39s
    2. Exercise files
      2m 16s
    3. What you should know
      1m 15s
  2. 7m 47s
    1. What is an object?
      2m 6s
    2. What is a class?
      2m 7s
    3. Why should you use object-oriented programming?
      2m 14s
    4. The history of object-oriented PHP
      1m 20s
  3. 16m 40s
    1. Defining a class
      2m 58s
    2. Defining class properties
      3m 26s
    3. Creating a method and exploring object context with $this
      2m 50s
    4. Instantiating an object and accessing its contents
      3m 19s
    5. Specifying the visibility scope
      4m 7s
  4. 15m 51s
    1. What is a magic method, and do I need one?
      2m 23s
    2. Overloading property access
      6m 37s
    3. Customizing object construction
      4m 34s
    4. Standardizing object rendering as a string
      2m 17s
  5. 20m 54s
    1. Using the static keyword
      3m 36s
    2. Leveraging scope resolution operators
      1m 10s
    3. Setting constant values
      2m 47s
    4. Implementing static methods
      5m 43s
    5. Creating a database class
      7m 38s
  6. 26m 19s
    1. Extending your class
      6m 8s
    2. Abstracting classes
      5m 57s
    3. Sharing interfaces using polymorphism
      4m 39s
    4. Overriding methods, properties, and constants
      3m 25s
    5. Cloning and comparing objects
      2m 51s
    6. Referencing objects
      3m 19s
  7. 14m 52s
    1. Leveraging standard class objects
      2m 42s
    2. Retrieving objects from the database
      5m 41s
    3. Error handling with exceptions
      2m 6s
    4. Customizing PHP exceptions
      4m 23s
  8. 8m 2s
    1. Identifying the singleton pattern
      1m 42s
    2. Using the factory method pattern
      1m 51s
    3. Implementing a strategy pattern
      4m 29s
  9. 2m 57s
    1. Looking forward to namespaces
      47s
    2. Next steps
      1m 6s
    3. Goodbye
      1m 4s

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