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package org.glassfish.javaee.services;

import com.sun.appserv.connectors.internal.api.ResourceNamingService;
import org.glassfish.resource.common.ResourceInfo;
import org.glassfish.api.naming.NamingObjectProxy;
import org.jvnet.hk2.annotations.Inject;
import org.jvnet.hk2.annotations.Service;
import org.jvnet.hk2.annotations.Scoped;
import org.jvnet.hk2.component.Habitat;
import org.jvnet.hk2.component.PerLookup;

import javax.naming.Context;
import javax.naming.NamingException;

import com.sun.appserv.connectors.internal.spi.ResourceDeployer;
import com.sun.enterprise.config.serverbeans.Resource;

import java.util.Collection;


/**
 * Represents the proxy object for a resource. Proxy will be bound in jndi
 * during startup and the actual <i>resource</i> will be deployed during
 * first lookup
 *
 * @author Jagadish Ramu
 */
@Service
@Scoped(PerLookup.class)
public class ResourceProxy implements NamingObjectProxy.InitializationNamingObjectProxy {

    @Inject
    private Habitat deployerHabitat;

    @Inject
    private ResourceNamingService namingService;

    private Resource resource = null;
    private Object result = null;
    private ResourceInfo resourceInfo = null;

    public Object create(Context ic) throws NamingException {
        //this is a per-lookup object and once we have the resource,
        //we remove the proxy and bind the resource (ref) with same jndi-name
        //hence block synchronization is fine as it blocks only callers
        //of this particular resource and also only for first time (initialization)
        synchronized(this){
            try{
                if(result == null){
                    getResourceDeployer(resource).deployResource(resource, resourceInfo.getApplicationName(),
                            resourceInfo.getModuleName());
                }
                result = namingService.lookup(resourceInfo, resourceInfo.getName(), ic.getEnvironment());
            }catch(Exception e){
                throwResourceNotFoundException(e, resourceInfo);
            }
        }
        return result;
    }

    /**
     * Set the resource config bean instance
     * @param resource config bean
     */
    public void setResource(Resource resource){
        this.resource = resource;
    }


    /**
     * Name by which the proxy (or the resource) will be bound in JNDI
     * @param resourceInfo resource-info
     */
    public void setResourceInfo(ResourceInfo resourceInfo) {
        this.resourceInfo = resourceInfo;
    }

    protected Object throwResourceNotFoundException(Exception e, ResourceInfo resourceInfo) throws NamingException {
        NamingException ne = new NamingException("Unable to lookup resource : " + resourceInfo);
        ne.initCause(e);
        throw ne;
    }

    /**
     * Given a <i>resource</i> instance, appropriate deployer will be provided
     *
     * @param resource resource instance
     * @return ResourceDeployer
     */
    protected ResourceDeployer getResourceDeployer(Object resource){
        Collection<ResourceDeployer> deployers = deployerHabitat.getAllByContract(ResourceDeployer.class);

        for(ResourceDeployer deployer : deployers){
            if(deployer.handles(resource)){
                return deployer;
            }
        }
        return null;
    }
}