Difference between revisions of "Org.eclipse.higgins.idas.udi"

/*
 * A Context UDI is defined to be any string that can be used to obtain Context UDI Metadata.
 */
 
interface IContextUDI {
 
	public IContextUDIMetadata getContextUDIMetadata();
}
 
/*
 * Context UDI Metadata is defined to be everything needed to instantiate an IContext:
 *   - required: one or more Context Types
 *   - optional: the schema of the Context
 *   - optional: a configuration map of the Context
 */
 
interface IContextMetadata {
 
	public String[] getTypes();
	public String getSchema();
	public Map getConfiguration();
}

/*
 * An Entity UDI (also called Resource UDI) is defined to be any string that can be used to obtain Entity UDI Metadata.
 */
 
interface IEntityUDI {
 
	public IEntityUDIMetadata getEntityUDIMetadata();
}
 
/*
 * Entity UDI Metadata is defined to be everything needed to instantiate an IEntity:
 *   - required: Context UDI Metadata of the Context the Entity is in
 *   - required: A relative Entity ID which identifies the Entity within its Context
 */
 
interface IEntityUDIMetadata {
 
	public IContextUDIMetadata getContextUDIMetadata();
	public String getEntityID();
}

/*
 * An Attribute UDI is defined to be any string that can be used to obtain Attribute Metadata.
 */
 
interface IAttributeUDI {
 
	public IAttributeMetadata getAttributeMetadata();
}
 
/*
 * Attribute Metadata is defined to be everything needed to instantiate an IAttribute:
 *   - required: Entity Metadata of the Entity the Attribute belongs to
 *   - required: A relative Attribute ID which identifies the Attribute on its Entity
 */
 
interface IAttributeMetadata {
 
	public IEntityMetadata getEntityMetadata();
	public URI getAttributeID();
}

public class UDIResolver implements IConfigurableComponent, IConfigurableComponentFactory {
 
	private static UDIResolver impl = null;
 
	private List udiFactoryList;
 
	public UDIResolver() {
 
		this.udiFactoryList = new ArrayList();
	}
 
	public static synchronized UDIResolver getInstance() {
 
		if (impl == null) impl = new UDIResolver();
		return(impl);
	}
 
	public IConfigurableComponent getNewInstance() {
 
		return(new IdASRegistry());
	}
 
	public IConfigurableComponent getSingletonInstance() {
 
		return(getInstance());
	}
 
	/**
	 * Register the UDIFactorys from the configuration
	 */
	public void configure(Map mapGlobalSettings, String strComponentName, Map mapComponentSettings) throws Exception {
 
		List udiFactoryInstances = (List) mapComponentSettings.get("UDIFactoryInstancesList");
 
		this.udiFactoryList.clear();
 
		for (Iterator i = udiFactoryInstances.iterator(); i.hasNext(); ) {
 
			IUDIFactory udiFactory = (IUDIFactory) i.next();
 
			this.udiFactoryList.add(udiFactory);
		}
	}
 
	/**
	 * Parse a string into an IContextUDI by trying all registered IUDIFactorys
	 * until one succeeds.
	 */
	public IContextUDI parseContextUDI(String contextUDIStr) throws IdASException {
 
		IContextUDI contextUDI = null;
 
		for (Iterator i = this.udiFactoryList.iterator(); i.hasNext(); ) {
 
			IUDIFactory udiFactory = (IUDIFactory) i.next();
 
			contextUDI = udiFactory.parseContextUDI(contextUDIStr);
			if (contextUDI != null) break;
		}
 
		return(contextUDI);
	}
 
	/**
	 * Parse a string into an IEntityUDI by trying all registered IUDIFactorys
	 * until one succeeds.
	 */
	public IEntityUDI parseEntityUDI(String entityUDIStr) throws IdASException {
 
		IEntityUDI entityUDI = null;
 
		for (Iterator i = this.udiFactoryList.iterator(); i.hasNext(); ) {
 
			IUDIFactory udiFactory = (IUDIFactory) i.next();
 
			entityUDI = udiFactory.parseEntityUDI(entityUDIStr);
			if (entityUDI != null) break;
		}
 
		return(entityUDI);
	}
 
	/**
	 * Parse a string into an IAttributeUDI by trying all registered IUDIFactorys
	 * until one succeeds.
	 */
	public IAttributeUDI parseAttributeUDI(String attributeUDIStr) throws IdASException {
 
		IAttributeUDI attributeUDI = null;
 
		for (Iterator i = this.udiFactoryList.iterator(); i.hasNext(); ) {
 
			IUDIFactory udiFactory = (IUDIFactory) i.next();
 
			attributeUDI = udiFactory.parseAttributeUDI(attributeUDIStr);
			if (attributeUDI != null) break;
		}
 
		return(attributeUDI);
	}
 
	/**
	 * Resolve an IContextUDI to an IContext by retrieving the IContextUDIMetadata
	 */
	public IContext resolve(IContextUDI contextUDI, Object authentication) throws IdASException {
 
		IContextUDIMetadata contextUDIMetadata = contextUDI.getContextMetadata();
 
		return(this.resolve(contextUDIMetadata, authentication));
	}
 
	/**
	 * Resolve an IEntityUDI to an IEntity by retrieving the IEntityUDIMetadata
	 */
	public IEntity resolve(IEntityUDI entityUDI, Object authentication) throws IdASException {
 
		IEntityUDIMetadata entityUDIMetadata = entityUDI.getEntityUDIMetadata();
 
		return(this.resolve(entityUDIMetadata, authentication));
	}
 
	/**
	 * Resolve an IAttributeUDI to an IAttribute by retrieving the IAttributeUDIMetadata
	 */
	public IAttribute resolve(IAttributeUDI attributeUDI, Object authentication) throws IdASException {
 
		IAttributeUDIMetadata attributeUDIMetadata = attributeUDI.getAttributeUDIMetadata();
 
		return(this.resolve(attributeUDIMetadata, authentication));
	}
 
	/**
	 * With the IContextUDIMetadata, we have everything we need to instantiate the IContext.
	 */
	private IContext resolve(IContextUDIMetadata contextUDIMetadata, Object authentication) throws IdASException {
 
		IdASRegistry idasRegistry = IdASRegistry.getInstance();
 
		String[] types = contextUDIMetadata.getTypes();
		Map configuration = contextUDIMetadata.getConfiguration();
 
		IContextFactory contextFactory = idasRegistry.getContextFactory(types);
 
		IContext context = contextFactory.createContext(configuration);
		context.open(authentication);
 
		return(context);
	}
 
	/**
	 * With the IEntityUDIMetadata, we have everything we need to instantiate the IContext and the IEntity.
	 */
	private IEntity resolve(IEntityUDIMetadata entityUDIMetadata, Object authentication) throws IdASException {
 
		IContextUDIMetadata contextUDIMetadata = entityUDIMetadata.getContextUDIMetadata();
		String entityID = entityUDIMetadata.getEntityID();
 
		IContext context = this.resolve(contextUDIMetadata, authentication);
		IEntity entity = context.getEntity(entityID);
 
		return(entity);
	}
 
	/**
	 * With the IAttributeUDIMetadata, we have everything we need to instantiate the IContext, the IEntity, and the IAttribute.
	 */
	private IAttribute resolve(IAttributeUDIMetadata attributeUDIMetadata, Object authentication) throws IdASException {
 
		IEntityUDIMetadata entityUDIMetadata = attributeUDIMetadata.getEntityUDIMetadata();
		URI attributeID = attributeUDIMetadata.getAttributeID();
 
		IEntity entity = this.resolve(entityUDIMetadata, authentication);
		IAttribute attribute = entity.getAttribute(attributeID);
 
		return(attribute);
	}
}

public interface IUDIFactory {
 
	public IContextUDI parseContextUDI(String contextUDI);
	public IEntityUDI parseEntityUDI(String entityUDI);
	public IAttributeUDI parseAttributeUDI(String attributeUDI);
}