net.greencoding.thysdrus.circuitbreaker.aspectj.CircuitBreakerAspect.java Source code

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Here is the source code for net.greencoding.thysdrus.circuitbreaker.aspectj.CircuitBreakerAspect.java

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/*
 * Copyright 2010 Nabil Ben Said.
 *
 * 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 net.greencoding.thysdrus.circuitbreaker.aspectj;

import net.greencoding.thysdrus.circuitbreaker.annotation.MonitoredByCircuitBreaker;
import net.greencoding.thysdrus.circuitbreaker.core.handler.CircuitBreakerHandler;
import net.greencoding.thysdrus.circuitbreaker.core.handler.DefaultCircuitBreakerHandler;
import net.greencoding.thysdrus.circuitbreaker.core.handler.MethodInvocationResult;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 
 * @author Nabil Ben Said (nabil.bensaid@gmail.com)
 * 
 */
@Aspect
public class CircuitBreakerAspect {

    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    //private final static String ANNOTATION_SIGNATURE =  MonitoredByCircuitBreaker.class.getName();
    private final static String ANNOTATION_SIGNATURE = "net.greencoding.thysdrus.circuitbreaker.annotation.MonitoredByCircuitBreaker";
    private final static String POINTCUT = "execution(@" + ANNOTATION_SIGNATURE
            + " * * (..)) && @annotation(annotation)";

    private AnnotationDiscoverer annotationDiscoverer = new CircuitBreakerAnnotationDiscoverer();

    public CircuitBreakerAspect() {
        annotationDiscoverer.discover();
    }

    private CircuitBreakerHandler cbHandler = DefaultCircuitBreakerHandler.getSingleton();

    @Around(POINTCUT)
    public Object breakCircuit(final ProceedingJoinPoint pjp, final MonitoredByCircuitBreaker annotation)
            throws Throwable {

        String circuitBreakerKey = getCircuitBreakerKey(pjp.getSignature().toLongString(), annotation);
        logger.info("CB: {}", circuitBreakerKey);
        MethodInvocationResult methodInvocationResult = cbHandler.handleMethodInvocation(pjp, circuitBreakerKey);
        if (methodInvocationResult.getReturnObject() != null) {
            return methodInvocationResult.getReturnObject();
        } else if (methodInvocationResult.getCause() != null) {
            throw methodInvocationResult.getCause();
        } else {
            return null;
        }
    }

    private String getCircuitBreakerKey(final String methodSignature,
            final MonitoredByCircuitBreaker cbAnnotation) {
        return cbAnnotation.groupId().isEmpty() ? methodSignature : cbAnnotation.groupId();
    }

}