package org.wamblee.system.spring;

import org.springframework.beans.factory.FactoryBean;
import org.wamblee.system.ProvidedInterface;
import org.wamblee.system.RequiredInterface;
import org.wamblee.system.SystemAssemblyException;

/**
 * Bean which adds a service required by the spring component to 
 * the application context so that other spring beans can use it.  
 *  
 * @author Erik Brakkee
 */
class RequiredServiceBean implements FactoryBean {
	
	private RequiredInterface _required; 
	
	/**
	 * Constructs the bean. 
	 * @param aId Id of the bean in the service registry.  
	 */
	public RequiredServiceBean(String aId) { 
		RequiredInterface[] required = SpringComponent.THIS.get().getRequiredServices();
		for ( RequiredInterface intf: required) { 
			if ( intf.getName().equals(aId)) { 
				_required = intf; 
				return;
			}
		}
		throw new SystemAssemblyException("Cannot resolve provided component '" + aId + "'");
	}

	@Override
	public Object getObject() throws Exception {
		return _required.getImplementation(Object.class);
	}

	@Override
	public Class getObjectType() {
		return null;
	}

	@Override
	public boolean isSingleton() {
		return true; 
	}

}