? PHP Custom Exception Classes

? Quick Overview

Custom exception classes allow developers to define specialized error types in PHP. By extending the built-in Exception class, you gain better control, cleaner code structure, and more meaningful error handling.

? Key Concepts

• Custom exceptions extend the built-in Exception class
• They allow categorization of different error types
• Additional methods can be added for logging or formatting

? Syntax & Theory

A custom exception is created using the class keyword and the extends Exception syntax. You can define custom methods to enhance error messages or behaviors.

// Define a custom exception class
<?php
class MyCustomException extends Exception {
    public function errorMessage() {
        // Build and return a detailed error message
        return "Error on line " . $this->getLine() . ": " . $this->getMessage();
    }
}

// Throw and catch the custom exception
try {
    throw new MyCustomException("Something went wrong!");
}
catch (MyCustomException $e) {
    echo $e->errorMessage();
}
?>

? Interactive Visualization

Exception Flow

? Use Cases

• Database connection failures
• File upload or read/write errors
• API or external service failures
• Validation and business logic errors