/**
    * Copyright 2005-2014 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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.kuali.rice.krad.config;
  
  import org.apache.commons.lang.StringUtils;
  import org.kuali.rice.core.api.config.ConfigurationException;
  import org.kuali.rice.core.api.resourceloader.GlobalResourceLoader;
  import org.kuali.rice.core.framework.util.ApplicationThreadLocal;
  import org.springframework.beans.factory.FactoryBean;
  import org.springframework.beans.factory.InitializingBean;
  
  import javax.xml.namespace.QName;
  
  /**
   * Exports services in the {@link org.kuali.rice.core.api.resourceloader.GlobalResourceLoader} as beans available to Spring.
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   *
   */
  public class GlobalResourceLoaderServiceFactoryBean implements FactoryBean<Object>, InitializingBean {
  
      private String serviceNamespace;
  	private String serviceName;
  	private boolean singleton;
  	private boolean mustExist;
  
  	// used to prevent a stack overflow when trying to get the service
  	private ThreadLocal<Boolean> isFetchingService = new ApplicationThreadLocal<Boolean>() {
          @Override
          protected Boolean initialValue() {
              return false;
          }
  	};
  	
  	public GlobalResourceLoaderServiceFactoryBean() {
  		this.mustExist = true;
  	}
  	
  	public Object getObject() throws Exception {
  		if (isFetchingService.get()) return null; // we already have been invoked, don't recurse, just return null.
  		isFetchingService.set(true);
  		try {
              Object service = null;
              if (StringUtils.isBlank(getServiceNamespace())) {
  			    service = GlobalResourceLoader.getService(this.getServiceName());
              } else {
                  service = GlobalResourceLoader.getService(new QName(getServiceNamespace(), getServiceName()));
              }
  			if (mustExist && service == null) {
  				throw new IllegalStateException("Service must exist and no service could be located with serviceNamespace='" + getServiceNamespace() + "' and name='" + this.getServiceName() + "'");
  			}
  			return service;
  		} finally {
  			isFetchingService.remove();
  		}
  	}
  
  	public Class<?> getObjectType() {
  		return Object.class;
  	}
  
  	public boolean isSingleton() {
  		return singleton;
  	}
  
      public String getServiceNamespace() {
          return serviceNamespace;
      }
  
      public void setServiceNamespace(String serviceNamespace) {
          this.serviceNamespace = serviceNamespace;
      }
  
      public String getServiceName() {
  		return serviceName;
  	}
  
  	public void setServiceName(String serviceName) {
  		this.serviceName = serviceName;
  	}
  
  	public void setSingleton(boolean singleton) {
  		this.singleton = singleton;
  	}
  	
  	public boolean isMustExist() {
 		return mustExist;
 	}
 	
 	public void setMustExist(boolean mustExist) {
 		this.mustExist = mustExist;
 	}
 	
 
 	public void afterPropertiesSet() throws Exception {
 		if (StringUtils.isBlank(this.getServiceName())) {
 			throw new ConfigurationException("No serviceName given.");
 		}
 	}
 
 }