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Resilience4j is a lightweight, easy-to-use fault tolerance library designed for Java8 and functional programming

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/*
 * Copyright 2020 Michael Pollind, Mahmoud Romeh
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.github.resilience4j.micronaut;

import io.micronaut.aop.MethodInvocationContext;
import io.micronaut.discovery.exceptions.NoAvailableServiceException;
import io.micronaut.inject.MethodExecutionHandle;
import io.micronaut.retry.exception.FallbackException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Optional;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionException;
import java.util.concurrent.CompletionStage;

public abstract class BaseInterceptor {
    private static final Logger logger = LoggerFactory.getLogger(BaseInterceptor.class);

    public abstract Optional> findFallbackMethod(MethodInvocationContext context);

    /**
     * Resolves a fallback for the given execution context and exception.
     *
     * @param context   The context
     * @param exception The exception
     * @return Returns the fallback value or throws the original exception
     */
    public Object fallback(MethodInvocationContext context, Throwable exception) {
        if (exception instanceof NoAvailableServiceException) {
            NoAvailableServiceException ex = (NoAvailableServiceException) exception;
            if (logger.isErrorEnabled()) {
                logger.debug(ex.getMessage(), ex);
                logger.error("Type [{}] attempting to resolve fallback for unavailable service [{}]", context.getTarget().getClass().getName(), ex.getServiceID());
            }
        } else {
            if (logger.isErrorEnabled()) {
                logger.error("Type [{}]  executed with error: {}", context.getTarget().getClass().getName(), exception.getMessage(), exception);
            }
        }
        Optional> fallback = findFallbackMethod(context);
        if (fallback.isPresent()) {
            MethodExecutionHandle fallbackMethod = fallback.get();
            if (logger.isDebugEnabled()) {
                logger.debug("Type [{}] resolved fallback: {}", context.getTarget().getClass().getName(), fallbackMethod);
            }
            return fallbackMethod.invoke(context.getParameterValues());
        } else {
            if(exception instanceof RuntimeException) {
                throw (RuntimeException) exception;
            } else {
                throw new CompletionException(exception);
            }
        }
    }

    public CompletionStage fallbackForFuture(CompletionStage result, MethodInvocationContext context) {
        CompletableFuture