Multiple Exception Handling in single catch clause

Exception handling is a fundamental part of writing robust and maintainable applications. In CFML, exceptions are usually handled within try, catch, and finally blocks. Typically, developers use catch blocks to handle exceptions, but what if you need to handle multiple exceptions at once? In this blog, we’ll explore how to handle multiple exceptions in CFML’s catch statements effectively, improving error management in your ColdFusion applications.

Handling multiple exception in one catch clause allows:

1. Removes Redundancy
2. Code Simplification
3. Maintainability
4. Better Readability

Note: Combining other exception with “any” is not allowed as any in same catch clause will itself catch other exception as well

Syntax:

try{

}catch(a | b | c ex){
// do something
}catch(d | f e){
// do something
}

<cftry>
<cfcatch type="a" | "b" | "c" name="ex">
</cfcatch>
</cftry>

Example Without Multiple Catch exception

try {
    // Code that might throw exceptions
    throw(type="IOException", message="File not found error.");
    throw(type="SQLException", message="Database connection error.");
} catch (IOException e) {
         writeOutput("An Exception occurred: " & e.message);
}catch (SQLException e) {
        writeOutput("An Exception occurred: " & e.message); // redundant code
    }
}

With Multiple Catch exception

try {
    // Code that might throw exceptions
    throw(type="IOException", message="File not found error.");
    throw(type="SQLException", message="Database connection error.");
} catch (IOException | SQLException e) {
     writeOutput("An Exception occurred: " & e.message);
}

}

Example:

<cfscript>
    function validateUserInput(input) {
        try {
            // Simulate input validation
            if (len(input) == 0) {
                 throw(type="MissingFieldException", message="Input field is required.");
            } else if (len(input) < 5) {
                throw(type="ValidationException", message="Input is too short. Minimum length is 5 characters.");
            }
            writeOutput("Input is valid: " & input);
        }
        catch (MissingFieldException | ValidationException e) {
            // Catching both validation exceptions in one block
            writeOutput("Validation Error: " & e.message);
        }
    }
</cfscript>

<cfset validateUserInput("")> <!-- Empty input, MissingFieldException will be thrown -->
<cfset validateUserInput("abc")> <!-- Short input, ValidationException will be thrown -->

In the example above, we are simulating the validation of user input within a web form. The goal is to catch and handle two potential exceptions related to invalid input: