KernDX

Appearance

UTIL_Retry ​

Class · Group: Resilience

apex
global inherited sharing class UTIL_Retry

Factory for retry strategies with nested interface definitions. Provides a clean API for creating and configuring retry strategies with exponential or linear backoff. This factory pattern reduces namespace pollution by nesting the interface inside the factory class. Features: Nested interfaces for clean type organization Fluent configuration API Standard implementations (exponential, linear) Custom strategy support via interface Jitter support to prevent thundering herd

Since: 1.0

Example:

Example 1: Simple exponential backoff

apex
UTIL_Retry.Strategy strategy = UTIL_Retry.exponential();
UTIL_Retry.Context context = UTIL_Retry.newContext(1);
if(strategy.shouldRetry(context))
{
    Integer backoffSeconds = strategy.calculateBackoff(context);
    Datetime nextRetry = Datetime.now().addSeconds(backoffSeconds);
}

Example 2: Custom configuration

apex
UTIL_Retry.Strategy strategy = UTIL_Retry.exponential()
    .withMaxRetries(5)
    .withBaseBackoff(10)
    .withJitter(true);

Example 3: Custom strategy implementation

apex
public class RateLimitStrategy implements UTIL_Retry.Strategy
{
    public Boolean shouldRetry(UTIL_Retry.Context ctx)
    {
        return context.getRetryCount() < 3;
    }
    public Integer calculateBackoff(UTIL_Retry.Context ctx)
    {
        // Custom logic based on rate limit headers
        return 60; // Wait 1 minute for rate limit
    }
    // Implement fluent setters...
}

Properties ​

PropertyDescription
global interface ContextInterface defining the retry context.
global interface StrategyInterface defining the retry strategy logic.

Methods ​

MethodDescription
global static UTIL_Retry.Strategy dontRetryOnException(UTIL_Retry.Strategy base, Set<Type> exceptionTypes)Wraps an existing strategy with an exception-type denylist.
global static UTIL_Retry.Strategy exponential()Returns a standard exponential backoff strategy.
global static UTIL_Retry.Strategy linear()Returns a standard linear backoff strategy.
global static UTIL_Retry.Context newContext(Integer retryCount)Creates a new retry context with the specified retry count.
global static UTIL_Retry.Strategy retryOnlyOnException(UTIL_Retry.Strategy base, Set<Type> exceptionTypes)Wraps an existing strategy with an exception-type allowlist.

Method Details ​

dontRetryOnException ​

apex
global static UTIL_Retry.Strategy dontRetryOnException(UTIL_Retry.Strategy base, Set<Type> exceptionTypes)

Wraps an existing strategy with an exception-type denylist. The wrapped strategy delegates calculateBackoff and the fluent setters (withMaxRetries, etc.) to the base strategy, but shouldRetry returns false whenever the caught exception (passed via Context.withCustomData(Exception)) matches any type in the denylist by exact type name (e.g. System.IllegalArgumentException). Subclass relationships are NOT considered — denylisting Exception.class does not catch concrete subclasses; list each concrete type explicitly. Use for "never retry on these errors" cases — e.g. authentication failures that won't recover via retry.

Wrapping (rather than adding setters to the Strategy interface) keeps the contract for subscriber Strategy implementations unchanged.

Parameters:

  • base (UTIL_Retry.Strategy) - The base retry strategy to wrap.
  • exceptionTypes (Set) - Set of exception types that should NEVER be retried.

Returns: UTIL_Retry.Strategy - A wrapped Strategy that suppresses retries when the caught exception matches any type in the denylist.

Since: 1.0

Example:

apex
UTIL_Retry.Strategy strategy = UTIL_Retry.dontRetryOnException(
        UTIL_Retry.exponential().withMaxRetries(5),
        new Set<Type>{System.IllegalArgumentException.class}
);
UTIL_Retry.Context context = UTIL_Retry.newContext(0).withCustomData(caughtException);
Boolean shouldRetry = strategy.shouldRetry(context);

exponential ​

apex
global static UTIL_Retry.Strategy exponential()

Returns a standard exponential backoff strategy. Defaults: max retries = 3, base backoff = 10s, jitter = false

Returns: UTIL_Retry.Strategy - Configured exponential backoff strategy

Since: 1.0

Example:

apex
UTIL_Retry.Strategy strategy = UTIL_Retry.exponential()
    .withMaxRetries(5)
    .withJitter(true);

linear ​

apex
global static UTIL_Retry.Strategy linear()

Returns a standard linear backoff strategy. Defaults: max retries = 3, base backoff = 10s

Returns: UTIL_Retry.Strategy - Configured linear backoff strategy

Since: 1.0

Example:

apex
UTIL_Retry.Strategy strategy = UTIL_Retry.linear()
    .withMaxRetries(5)
    .withBaseBackoff(15);

newContext ​

apex
global static UTIL_Retry.Context newContext(Integer retryCount)

Creates a new retry context with the specified retry count.

Parameters:

  • retryCount (Integer) - The current retry attempt number (0 = first attempt, 1 = first retry, etc.)

Returns: UTIL_Retry.Context - New context instance

Since: 1.0

Example:

apex
UTIL_Retry.Context context = UTIL_Retry.newContext(1)
    .withLastAttemptTime(Datetime.now())
    .withCustomData(apiCall);

retryOnlyOnException ​

apex
global static UTIL_Retry.Strategy retryOnlyOnException(UTIL_Retry.Strategy base, Set<Type> exceptionTypes)

Wraps an existing strategy with an exception-type allowlist. The wrapped strategy delegates everything to the base, but shouldRetry returns false UNLESS the caught exception (passed via Context.withCustomData(Exception)) matches one of the allowed types by exact type name. Subclass relationships are NOT considered. Use for "only retry on these errors" cases — e.g. a narrow set of transient errors a remote service might throw.

Calls without a caught Exception in Context.getCustomData() always retry per the base strategy (the allowlist only applies when an exception is present).

Parameters:

  • base (UTIL_Retry.Strategy) - The base retry strategy to wrap.
  • exceptionTypes (Set) - Set of exception types that ARE allowed to be retried. Empty or null disables the filter (delegates fully to base).

Returns: UTIL_Retry.Strategy - A wrapped Strategy that only retries when the caught exception matches an allowed type.

Since: 1.0

Example:

apex
UTIL_Retry.Strategy strategy = UTIL_Retry.retryOnlyOnException(
        UTIL_Retry.exponential().withMaxRetries(5),
        new Set<Type>{System.CalloutException.class}
);