Choosing Between Static and Non-Static Methods in PHP: Real-World Use Cases and Code Examples
Tags: static, nonstatic, php, staticvsnonstaticmethodsinphp
Published: 2023-07-07 19:18:52

## Introduction
In PHP development, selecting between static and non-static methods holds significant importance when it comes to code organization and functionality. Both approaches provide unique benefits and are applicable in different scenarios. This article aims to examine the utilization of static and non-static methods in PHP using practical illustrations. By comprehending the appropriate usage of each approach, you can design code that is more effective and easier to maintain.

## Scenarios to use static methods:

**1. Data validation utility:**
Demonstrating a static method for email validation, which can be accessed without instantiating the class.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/zj7672bxg58g66cft05j.png)

**2. Logging utility:**
Implementing a static method to handle logging functionality for easy access throughout the application.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ictd6nkgy8nkdaij1mv4.png)

**3. Factory Methods:**
Static methods can be used as factory methods to create instances of a class, encapsulating the object creation logic.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/1nyw9fr0upqxo2udtnwn.png)

**3. Configuration Handling:***
Static methods can be useful for handling configuration settings or retrieving values from a configuration file.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ikt9lp013ia3888la4bq.png)


## Scenarios to use non-static methods:
**1. Order Processing:**
Illustrating a non-static method to add items to an order and process the order using instance-specific data.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/brc59n7rs25kf8s1k21b.png)

So, now you may have a question here, something like - what would happen, if we used static methods here.
Don't worry, here is the reason :

If we were to use static methods in the Order class instead of non-static methods, several consequences would arise. Firstly, static methods do not have access to instance-specific data, such as the items array, as they operate at the class level rather than on individual objects. This would lead to shared data among all instances of the class, making it impossible to maintain separate order details. Secondly, encapsulation and re-usability would be compromised, as static methods cannot encapsulate functionality and data within specific instances, hindering code organization and modularity. Lastly, static methods lack the flexibility of dependency management, as they are not designed to handle dynamic dependencies, making it difficult to inject additional services or dependencies. 

In summary, using static methods would result in shared data, reduced encapsulation, limited re-usability, and inadequate dependency management within the Order class.

**2. Database Connection Wrapper:**
Creating a non-static method to establish a database connection and perform queries using the instance-specific connection.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/bwddyz3tt4bobdo3zfav.png)

So far, I have shown the example code for static and non-static methods separately. Now, it is turn to show an example code to use both static and non-static methods together:

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/gnc3npa03fxkbvrrtn1f.png)

I hope, by this far, you have understood when to use static method and when not to use. 

I can share with you one more scenario that we have faced or face many times while writing code in for example, service classes. We need to think which methods in a service class will be static or non-static. So, here is a check list to identify if you need to write a method static or non-static:

**Use Non-Static Methods When:**

1. Instance-Specific Data: When you need to access or modify data specific to each object instance.

2. Encapsulation and Reusability: When you want to encapsulate functionality and data within individual instances, promoting better code organization and modularity.

3. Independent Processing: When each object should be able to perform operations independently without affecting other instances.

4. Dependency Management: When you require the flexibility of injecting additional services or dependencies as constructor arguments or method parameters.

**Use Static Methods When:**

1. Class-Level Operations: When the functionality does not depend on or modify instance-specific data and can be performed at the class level.

2. Utility Functions: When the method provides common utility functions that do not rely on instance state.

3. Global Operations: When the functionality is applicable across multiple instances and does not require individual data.

By taking these guidelines into consideration, you can make well-informed choices regarding the usage of static or non-static methods that align with the specific requirements of your PHP code.