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Diffstat (limited to 'TAO/orbsvcs/ImplRepo_Service/LiveCheck.h')
| -rw-r--r-- | TAO/orbsvcs/ImplRepo_Service/LiveCheck.h | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/TAO/orbsvcs/ImplRepo_Service/LiveCheck.h b/TAO/orbsvcs/ImplRepo_Service/LiveCheck.h new file mode 100644 index 00000000000..1170a056c03 --- /dev/null +++ b/TAO/orbsvcs/ImplRepo_Service/LiveCheck.h @@ -0,0 +1,177 @@ +// -*- C++ -*- +/* + * @file LiveCheck.h + * + * $Id$ + * + * @author Phil Mesnier <mesnier_p@ociweb.com> + */ + +#ifndef IMR_LIVECHECK_H_ +#define IMR_LIVECHECK_H_ + +#include "locator_export.h" + +#include "tao/ImR_Client/ServerObjectS.h" // ServerObject_AMIS.h + +#include "ace/Vector_T.h" +#include "ace/Hash_Map_Manager.h" +#include "ace/SString.h" +#include "ace/Event_Handler.h" + +#if !defined (ACE_LACKS_PRAGMA_ONCE) +#pragma once +#endif /* ACE_LACKS_PRAGMA_ONCE */ + +class LiveCheck; + +/*--------------------------------------------------------------------------- + * @enum LiveStatus + * + * @brief indication of the known condition of a target server + * + * LS_UNKNOWN - The server hasn't yet been pinged + * LS_DEAD - The ping failed for reasons other than POA Activation + * LS_ALIVE - The server positively acknowledged a ping + * LS_TRANSIENT - The server connected, but acively raised a transient + * LS_TIMEDOUT - The server connected, but never returned any result. + */ +enum LiveStatus { + LS_UNKNOWN, + LS_DEAD, + LS_ALIVE, + LS_TRANSIENT, + LS_TIMEDOUT +}; + +/*--------------------------------------------------------------------------- + * @class LiveListener + * + * @brief An interface for receiving asynch liveness status updates + * + * The code waiting on a confirmation of liveness status creates an instance + * of a LiveListener and registers it with the LiveCheck object. + * When the desired ping occurs, the status_changed method is called and the + * listener is unregistered. It is up to the owner of the listener to re- + * register if the ping result was inconclusive, such as a status of TRANSIENT + * or TIMEDOUT. Such a decision is based on configuration settings. + */ +class Locator_Export LiveListener +{ + public: + /// Construct a new listener. The server name suppled is used to + /// look up a listener entry in the LiveCheck map. + LiveListener (const char *server); + + /// called by the asynch ping receiver when a reply or an exception + /// is received. + virtual void status_changed (LiveStatus status) = 0; + + /// accessor for the server name. Used by the LiveCheck to associate a listener + const ACE_CString & server (void) const; + + private: + ACE_CString server_; +}; + +/*--------------------------------------------------------------------------- + * @class LiveEntry + * + * @brief Contains a list of interested listeners for a server + * + * Each server the Locator is interested in has a live entry instance. + * This holds the liveliness status and determines the next allowed time + * for a ping. Instances of the LiveEntry class are retained until the + * locator is no longer interested in the target server. + */ +class Locator_Export LiveEntry +{ + public: + LiveEntry (LiveCheck *owner, ImplementationRepository::ServerObject_ptr ref); + ~LiveEntry (void); + + void add_listener (LiveListener * ll); + LiveStatus status (void) const; + void status (LiveStatus l); + bool do_ping (PortableServer::POA_ptr poa); + const ACE_Time_Value &next_check (void) const; + + private: + LiveCheck *owner_; + ImplementationRepository::ServerObject_var ref_; + LiveStatus liveliness_; + ACE_Time_Value next_check_; + short retry_count_; + bool ping_away_; + ACE_Vector<LiveListener *> listeners_; + TAO_SYNCH_MUTEX lock_; +}; + +/*--------------------------------------------------------------------------- + * @class PingReceiver + * + * @brief callback handler for asynch ping requests + * + * An instance of the ping receiver is used to handle the reply from a ping + * request. Instances are created for the ping, then destroyed. +`*/ +class Locator_Export PingReceiver : + public virtual POA_ImplementationRepository::AMI_ServerObjectHandler +{ + public: + PingReceiver (LiveEntry * entry, PortableServer::POA_ptr poa); + virtual ~PingReceiver (void); + + void ping (void); + void ping_excep (Messaging::ExceptionHolder * excep_holder); + + private: + PortableServer::POA_var poa_; + LiveEntry * entry_; +}; + +/*--------------------------------------------------------------------------- + * @class LiveCheck + * + * @brief The manager class used for pinging servers as needed. + * + * The LiveCheck class maintains a map of named LiveEntries. When the locator + * needs to determine the liveliness of a server, registers a LiveListener + * for the desired server. A ping to the server is then scheduled, based on the + * limits determined by the entry's state. + */ +class Locator_Export LiveCheck : public ACE_Event_Handler +{ + public: + LiveCheck (); + ~LiveCheck (void); + + void init (CORBA::ORB_ptr orb, const ACE_Time_Value &interval); + + int handle_timeout (const ACE_Time_Value ¤t_time, + const void *act = 0); + + void add_server (const char *server, + ImplementationRepository::ServerObject_ptr ref); + void remove_server (const char *server); + + void add_listener (LiveListener *waiter); + + LiveStatus is_alive (const char *server); + + const ACE_Time_Value &ping_interval (void) const; + + private: + typedef ACE_Hash_Map_Manager_Ex<ACE_CString, + LiveEntry *, + ACE_Hash<ACE_CString>, + ACE_Equal_To<ACE_CString>, + TAO_SYNCH_MUTEX> LiveEntryMap; + + LiveEntryMap entry_map_; + PortableServer::POA_var poa_; + ACE_Time_Value ping_interval_; +}; + +#endif /* IMR_LIVECHECK_H_ */ + |