//File: DAFUpdate.idl
#ifndef _DAF_UPDATE_IDL_
#define _DAF_UPDATE_IDL_

#include <DAFDescriptions.idl>

#pragma prefix "omg.org"
module DAFUpdate
{
	// types imported from the descriptions and identifiers modules
	typedef DAFDescriptions::ResourceDescription ResourceDescription;	
	typedef DAFIdentifiers::ResourceIDSequence ResourceIDSequence;

	// An Action is is the "verb" for an UpdateCommand structure.
	typedef short Action;
	const Action CREATE_RESOURCE_ACTION = 1;
	const Action SET_VALUES_ACTION = 2;
	const Action DELETE_RESOURCE_ACTION = 3;
	const Action ENFORCE_PRECONDITION_ACTION = 4;


	// an Update consists of a command and its associated data.
	struct UpdateCommand
	{
		Action action;
		ResourceDescription resource;
	};
	typedef sequence<Update> UpdateCommandSequence;

	// updates can raise these exeptions
	exception PreconditionFailed { string reason };
	exception UpdateError { string reason; };
	exception UnknownResource{ string reason; };

	// the update service
	interface ResourceUpdateService 
	{
		// generate identifiers for use in create_resource and CREATE_RESOURCE_ACTION 
		ResourceIDSequence create_resource_ids(
			in ResourceID prototype,
			in int how_many )
			raises ( UnknownResource );

		// create a new resource with the given description and identifier
		ResourceID create_resource( in ResourceDescription new_resource )
		 	raises( PreconditionFailed, UpdateError );

		// update the resource that matches precondition according to the resource description
		void set_values( 
			in ResourceDescription precondition,
			in ResourceDescription resource )
		 	raises( Preconditionfailed, UpdateError );

		// delete the resource that matches the given description
		void delete_resource( in ResourceDescription resource )
		 	raises( Preconditionfailed, UpdateError );

		// perform multiple updates in one operation
		void apply_updates( UpdateCommandSequence updates )
		 	raises( Preconditionfailed, UpdateError );
	};
};
#endif // _DAF_UPDATE_IDL_