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package com.sun.jersey.server.impl.ejb;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicBoolean;

import javax.annotation.ManagedBean;
import javax.annotation.PostConstruct;
import javax.interceptor.InvocationContext;
import javax.ws.rs.ext.Provider;

import com.sun.jersey.core.spi.component.ComponentScope;
import com.sun.jersey.core.spi.component.ioc.IoCComponentProcessor;
import com.sun.jersey.core.spi.component.ioc.IoCComponentProcessorFactory;

final class EJBInjectionInterceptor {

    private IoCComponentProcessorFactory cpf;

    private final ConcurrentMap<Class, IoCComponentProcessor> componentProcessorMap =
            new ConcurrentHashMap<Class, IoCComponentProcessor>();
    
    public void setFactory(IoCComponentProcessorFactory cpf) {
        this.cpf = cpf;
    }

	private final AtomicBoolean initializing = new AtomicBoolean(false);

    @PostConstruct
    private void init(final InvocationContext context) throws Exception {
        if (cpf == null) {
            // Not initialized
            return;
        }

        boolean setInitializing = initializing.compareAndSet(false, true);
        if (!setInitializing) {
            return;
        }
        final Object beanInstance = context.getTarget();
        final IoCComponentProcessor icp = get(beanInstance.getClass());
        if (icp != null) {
            icp.postConstruct(beanInstance);
        }

        // Invoke next interceptor in chain
        context.proceed();
    }

    private static final IoCComponentProcessor NULL_COMPONENT_PROCESSOR = new IoCComponentProcessor() {
        public void preConstruct() {
        }

        public void postConstruct(Object o) {
        }
    };
    
    private IoCComponentProcessor get(final Class c) {
        IoCComponentProcessor cp = componentProcessorMap.get(c);
        if (cp != null) {
            return (cp == NULL_COMPONENT_PROCESSOR) ? null : cp;
        }

        synchronized (componentProcessorMap) {
            cp = componentProcessorMap.get(c);
            if (cp != null) {
                return (cp == NULL_COMPONENT_PROCESSOR) ? null : cp;
            }

            final ComponentScope cs = c.isAnnotationPresent(ManagedBean.class)
                    ? c.isAnnotationPresent(Provider.class)
                        ? ComponentScope.Singleton
                        : cpf.getScope(c)
                    : ComponentScope.Singleton;
            cp = cpf.get(c, cs);
            if (cp != null) {
                componentProcessorMap.put(c, cp);
            } else {
                componentProcessorMap.put(c, NULL_COMPONENT_PROCESSOR);
            }
        }
        return cp;
    }
}
