How to Map Multiple Values to One Variant¶

Activate a single variant implementation from multiple flag values.

Goal¶

Route different flag values (e.g., "CLASSIC" and "LEGACY") to the same variant without duplicating code.

Prerequisites¶

FlagZen basics: @Feature, @Variant
Understanding of variant matching

Steps¶

1. Define multiple values in a single variant¶

Use array syntax in the @Variant value field:

@Feature("checkout-flow")
public interface CheckoutFlow {
    String execute();
}

@Variant(value = {"CLASSIC", "LEGACY"}, of = CheckoutFlow.class)
public class ClassicCheckout implements CheckoutFlow {
    @Override
    public String execute() { return "classic"; }
}

@Variant(value = "STREAMLINED", of = CheckoutFlow.class)
public class StreamlinedCheckout implements CheckoutFlow {
    @Override
    public String execute() { return "streamlined"; }
}

Now both "CLASSIC" and "LEGACY" flag values activate the ClassicCheckout variant.

2. For typed flags, use type-specific array fields¶

Provide arrays for numeric types:

@Feature(value = "retry-level", type = FeatureType.INT)
public interface RetryStrategy {
    int getMaxRetries();
}

@Variant(intValue = {3, 5, 7}, of = RetryStrategy.class)
public class ConservativeRetry implements RetryStrategy {
    @Override
    public int getMaxRetries() { return 3; }
}

Values 3, 5, and 7 all dispatch to ConservativeRetry.

3. Compose with `@Repeatable` for cleaner syntax (optional)¶

If you need complex variant definitions, repeat the @Variant annotation:

@Variant(value = "CLASSIC", of = CheckoutFlow.class)
@Variant(value = "LEGACY", of = CheckoutFlow.class)
public class ClassicCheckout implements CheckoutFlow { ... }

Both forms are equivalent. Use arrays for simple cases; use @Repeatable when variant logic is more complex.

4. Test with multiple values¶

provider.set("checkout-flow", "CLASSIC");
CheckoutFlow flow = dispatcher.resolve(CheckoutFlow.class);
flow.execute(); // ClassicCheckout

provider.set("checkout-flow", "LEGACY");
flow = dispatcher.resolve(CheckoutFlow.class);
flow.execute(); // Still ClassicCheckout

Result¶

A single variant implementation handles multiple flag values, reducing code duplication and keeping variant logic centralized.