Custom Errors in CLIPS

Custom error types in Java are typically implemented by extending the Exception class. Here’s an example that demonstrates a custom error type and its usage:

import java.util.function.Function;

// A custom exception type usually extends Exception or RuntimeException
class ArgError extends Exception {
    private int arg;
    private String message;

    public ArgError(int arg, String message) {
        super(arg + " - " + message);
        this.arg = arg;
        this.message = message;
    }

    public int getArg() {
        return arg;
    }

    public String getCustomMessage() {
        return message;
    }
}

public class CustomErrors {
    public static int f(int arg) throws ArgError {
        if (arg == 42) {
            // Throw our custom exception
            throw new ArgError(arg, "can't work with it");
        }
        return arg + 3;
    }

    public static void main(String[] args) {
        try {
            f(42);
        } catch (Exception e) {
            // In Java, we use instanceof to check the type of an exception
            if (e instanceof ArgError) {
                ArgError ae = (ArgError) e;
                System.out.println(ae.getArg());
                System.out.println(ae.getCustomMessage());
            } else {
                System.out.println("Exception doesn't match ArgError");
            }
        }
    }
}

In this Java example, we define a custom exception ArgError that extends the Exception class. This is similar to implementing the error interface in other languages.

The f method throws our custom exception when the input is 42. In the main method, we catch the exception and use instanceof to check if it’s an ArgError. This is similar to using errors.As in other languages.

To run this program:

$ javac CustomErrors.java
$ java CustomErrors
42
can't work with it

This example demonstrates how to create and use custom exceptions in Java, which is a common way to handle custom errors in Java applications.

Errors in CLIPS

Goroutines in CLIPS

Learn X By Example

Title here

Custom Errors in CLIPS