Requirements:
The maxAttempts variable must:
Preserve its value for the length of the Apex transaction.
Be able to share the variable's state between trigger executions.
Solution:
To meet these requirements, the variable should be declared as a private static variable on a helper class.
Option D: Declare maxAttempts as a private static variable on a helper class.
Correct Approach.
Static Variables:
Static variables retain their value throughout the execution context of the Apex transaction.
They are shared across trigger contexts and can be used to maintain state between trigger executions.
Private Modifier:
Keeps the variable encapsulated within the class.
Helper Class:
Placing the variable in a helper class allows it to be accessed from multiple triggers or classes within the transaction.
Sample Code:
public class MyHelperClass {
private static Integer maxAttempts = 0;
public static void incrementAttempts() {
maxAttempts++;
}
public static Integer getMaxAttempts() {
return maxAttempts;
}
}
Benefits:
State Preservation: Static variables maintain their state during the transaction.
Accessibility: Can be accessed from different triggers or classes.
Declaring as static final makes the variable a constant.
Constants cannot change value once initialized.
We need the variable to preserve and change its value during the transaction.
Option B: Declare maxAttempts as a member variable on the trigger definition.
Not Possible.
You cannot declare variables directly on the trigger definition.
Triggers do not support member variables.
Option C: Declare maxAttempts as a variable on a helper class.
Insufficient.
Declaring it as an instance variable (non-static) on a helper class means it does not retain its value across trigger executions within the same transaction.
Each instantiation would have its own copy of the variable.
Conclusion:
Declaring maxAttempts as a private static variable on a helper class satisfies the requirements.
It ensures the variable retains its value throughout the Apex transaction and can be shared between trigger executions.
Reference:
Static and Instance Variables
Understanding Apex Transactions
Why Other Options are Not Suitable:
Option A: Declare maxAttempts as a constant using the static and final keywords.
Incorrect.