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package hydra.compute;

import hydra.Flows;
import hydra.core.Unit;

/**
 * A convenience class for stateless coders; we use Hydra's Unit as the state type.
 * Note: using Java's Void is problematic because of the interaction of Optional with null values.
 */
public class StatelessCoder extends Coder {

    public StatelessCoder(
            java.util.function.Function> encode,
            java.util.function.Function> decode) {
        super(encode, decode);
    }

    /**
     * Construct a stateless coder.
     */
    public static  StatelessCoder of(
            java.util.function.Function> encode,
            java.util.function.Function> decode) {
        return new StatelessCoder(encode, decode);
    }

    /**
     * Construct a unidirectional coder; encoding follows the provided function, while decoding will fail gracefully.
     */
    public static  StatelessCoder unidirectional(
            java.util.function.Function> encode) {
        return StatelessCoder.of(encode, v2 -> Flows.fail("decoding is not supported"));
    }
}