libraries/circuitbreaker/src/main/java/org/apache/zest/library/circuitbreaker/service/BreakCircuitConcern.java

/*
 * Copyright 2009-2010 Rickard Öberg AB
 *
 * 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 org.apache.zest.library.circuitbreaker.service;

import java.lang.reflect.Method;
import org.apache.zest.api.common.AppliesTo;
import org.apache.zest.api.concern.GenericConcern;
import org.apache.zest.api.injection.scope.This;
import org.apache.zest.library.circuitbreaker.CircuitBreaker;

/**
 * This concern will update the circuit breaker on method invocation success
 * and thrown exceptions.
 */
@AppliesTo( BreaksCircuitOnThrowable.class )
public class BreakCircuitConcern
        extends GenericConcern
{

    @This
    ServiceCircuitBreaker serviceCircuitBreaker;

    @Override
    public Object invoke( Object proxy, Method method, Object[] args )
            throws Throwable
    {
        CircuitBreaker circuitBreaker = serviceCircuitBreaker.circuitBreaker();
        try
        {
            if( !circuitBreaker.isOn() )
            {
                throw circuitBreaker.lastThrowable();
            }

            Object result = next.invoke( proxy, method, args );
            circuitBreaker.success();
            return result;
            
        } catch( Throwable throwable )
        {
            circuitBreaker.throwable( throwable );
            throw throwable;
        }
    }

}