Mute Idiom
Intent
Provide a template to suppress any exceptions that either are declared but cannot occur or should only be logged;
while executing some business logic. The template removes the need to write repeated try-catch blocks.
Explanation
Real World Example
The vending machine contained in your office displays a warning when making a transaction. The issue occurs when the
customer decides to pay with physical money that is not recognized by the system. However, you and everyone in the office
only pays with the company credit card and will never encounter this issue.
In plain words
The Mute Idiom design pattern is used to reduce the requirement of catching exceptions when they cannot be thrown or
should be ignored when thrown. This applies in cases such as API functions, where the underlying code cannot be changed
to include individual use cases.
Programmatic Example
Converting the real-world example into a programmatic representation, we represent an API function as the
office Vending machine
public class VendingMachine {
public void purchaseItem(int itemID, PaymentMethod paymentMethod) throws Exception {
if (paymentMethod == PaymentMethod.Cash) {
throw new Exception();
}
else {
System.out.println("Here is your item");
}
}
}
public enum PaymentMethod {
Card,Cash
}
We then run our office's daily routine, which involves purchasing items
from the vending machine with the company card, using the mute pattern to ignore the exceptions that can't be thrown
package com.iluwatar.mute;
public class Office {
private PaymentMethod companyCard = PaymentMethod.Card;
private VendingMachine officeVendingMachine = new VendingMachine();
public static void main(String[] args) {
Office office = new Office();
office.dailyRoutine();
}
public void dailyRoutine() {
Mute.mute(() -> {
officeVendingMachine.purchaseItem(1,companyCard);
officeVendingMachine.purchaseItem(1,companyCard);
officeVendingMachine.purchaseItem(1,companyCard);
});
}
}
Class diagram
Applicability
Use this idiom when
- an API declares some exception but can never throw that exception eg. ByteArrayOutputStream bulk write method.
- you need to suppress some exception just by logging it, such as closing a resource.