ServiceContextStoreInterceptor.java

/*
 * Copyright 2013 The Sculptor Project Team, including the original 
 * author or authors.
 * 
 * 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.sculptor.framework.context;

import javax.interceptor.AroundInvoke;
import javax.interceptor.InvocationContext;

/**
 * This interceptor stores the {@link ServiceContext}, which is passed in one of
 * the method parameters, in {@link ServiceContextStore}. After proceed, both
 * when returning and when exception, the {@link ServiceContextStore} will be
 * cleared.
 * 
 * @author Patrik Nordwall
 */
public class ServiceContextStoreInterceptor {

    @AroundInvoke
    public Object invoke(InvocationContext context) throws Exception {
        if (ServiceContextStore.get() != null) {
            // this is not the first advice and it should therefore be ignored
            // it is the first advice that is responsible for setting/clearing
            // the service context
            return context.proceed();
        }
        try {
            Object[] args = context.getParameters();
            if (args != null) {
                for (int i = 0; i < args.length; i++) {
                    if (args[i] instanceof ServiceContext) {
                        ServiceContextStore.set((ServiceContext) args[i]);
                        break;
                    }
                }
            }
            return context.proceed();
        } finally {
            ServiceContextStore.set(null);
        }
    }

}