package org.kuali.rice.ksb.impl.bus;
   
   import javax.xml.namespace.QName;
   
   import org.apache.commons.lang.StringUtils;
   import org.kuali.rice.ksb.api.bus.Endpoint;
   import org.kuali.rice.ksb.api.bus.ServiceConfiguration;
   import org.kuali.rice.ksb.api.registry.ServiceDescriptor;
   import org.kuali.rice.ksb.api.registry.ServiceInfo;
  import org.kuali.rice.ksb.api.registry.ServiceRegistry;
  
  public final class RemoteService {
  	
  	private final ServiceInfo serviceInfo;
  	private final ServiceRegistry serviceRegistry;
  	
  	private final Object endpointAcquisitionLock = new Object();
  	private volatile Endpoint endpoint;
  	
  	public RemoteService(ServiceInfo serviceInfo, ServiceRegistry serviceRegistry) {
  		validateServiceInfo(serviceInfo);
  		if (serviceRegistry == null) {
  			throw new IllegalArgumentException("serviceRegistry cannot be null");
  		}
  		this.serviceInfo = serviceInfo;
  		this.serviceRegistry = serviceRegistry;
  	}
  	
  	private static void validateServiceInfo(ServiceInfo serviceInfo) {
  		if (serviceInfo == null) {
  			throw new IllegalArgumentException("serviceInfo cannot be null");
  		}
  		if (serviceInfo.getServiceId() == null) {
  			throw new IllegalArgumentException("serviceInfo must have a serviceId but was null");
  		}
  	}
  	
  	public QName getServiceName() {
  		return serviceInfo.getServiceName();
  	}
  		
  	public ServiceInfo getServiceInfo() {
  		return serviceInfo;
  	}
  	
  	public Endpoint getEndpoint() {
  		// double-checked locking idiom - see Effective Java, Item 71
  		Endpoint internalEndpoint = this.endpoint;
  		if (internalEndpoint == null) {
  			synchronized (endpointAcquisitionLock) {
  				internalEndpoint = this.endpoint;
  				if (internalEndpoint == null) {
  					this.endpoint = internalEndpoint = new LazyEndpoint(constructServiceConfiguration()); 
  				}
  			}
  		}
  		return internalEndpoint;
  	}
  	
  	protected ServiceConfiguration constructServiceConfiguration() {
  		ServiceDescriptor serviceDescriptor = serviceRegistry.getServiceDescriptor(serviceInfo.getServiceDescriptorId());
  		if (serviceDescriptor == null) {
  			throw new IllegalStateException("Failed to locate ServiceDescriptor for ServiceInfo with serviceDescriptorId=" + serviceInfo.getServiceDescriptorId());
  		} else if (StringUtils.isBlank(serviceDescriptor.getDescriptor())) {
  			throw new IllegalStateException("ServiceDescriptor descriptor value is blank or null for descriptor with serviceEndpointId=" + serviceInfo.getServiceId());
  		}
  		return ServiceConfigurationSerializationHandler.unmarshallFromXml(serviceDescriptor.getDescriptor());
  	}
  	
  	@Override
      public boolean equals(Object obj) {
  		if (!(obj instanceof RemoteService)) {
  			return false;
  		}
  		return serviceInfo.equals(((RemoteService)obj).getServiceInfo());
      }
  
  	@Override
      public int hashCode() {
          return serviceInfo.hashCode();
      }
  	
  }