SuccessFailure.java

package jp.sample.android.lib.type;

import android.support.annotation.NonNull;

public final class SuccessFailure<Success, Failure> {

    public interface SuccessResult<Success> {
        void result(Success successResult);
    }

    public interface FailureResult<Failure> {
        void result(Failure failureResult);
    }

    private enum Type {
        SUCCESS,
        FAILURE,
    }

    private final Type type;
    private final Success successResult;
    private final Failure failureResult;

    private SuccessFailure(Type type, Success successResult, Failure failureResult) {
        this.type = type;
        this.successResult = successResult;
        this.failureResult = failureResult;
    }

    public static <Success, Failure> SuccessFailure<Success, Failure> success(@NonNull Success successResult) {
        return new SuccessFailure<>(Type.SUCCESS, successResult, null);
    }

    public static <Success, Failure> SuccessFailure<Success, Failure> failure(@NonNull Failure failureResult) {
        return new SuccessFailure<>(Type.FAILURE, null, failureResult);
    }

    public void apply(SuccessResult<Success> successResult, FailureResult<Failure> failureResult) {
        if (type == Type.SUCCESS) {
            successResult.result(this.successResult);
        } else if (type == Type.FAILURE) {
            failureResult.result(this.failureResult);
        }
    }
}