sl@0: /**
sl@0:  *******************************************************************************
sl@0:  * Copyright (C) 2001-2004, International Business Machines Corporation and    *
sl@0:  * others. All Rights Reserved.                                                *
sl@0:  *******************************************************************************
sl@0:  */
sl@0: #ifndef ICUNOTIF_H
sl@0: #define ICUNOTIF_H
sl@0: 
sl@0: #include "unicode/utypes.h"
sl@0: 
sl@0: #if UCONFIG_NO_SERVICE
sl@0: 
sl@0: U_NAMESPACE_BEGIN
sl@0: 
sl@0: /*
sl@0:  * Allow the declaration of APIs with pointers to BreakIterator
sl@0:  * even when break iteration is removed from the build.
sl@0:  */
sl@0: class ICUNotifier;
sl@0: 
sl@0: U_NAMESPACE_END
sl@0: 
sl@0: #else
sl@0: 
sl@0: #include "unicode/uobject.h"
sl@0: #include "unicode/unistr.h"
sl@0: 
sl@0: #include "mutex.h"
sl@0: #include "uvector.h"
sl@0: 
sl@0: U_NAMESPACE_BEGIN
sl@0: 
sl@0: class U_COMMON_API EventListener : public UObject {
sl@0: public: 
sl@0:     virtual ~EventListener();
sl@0: 
sl@0: public:
sl@0:     static UClassID U_EXPORT2 getStaticClassID();
sl@0: 
sl@0:     virtual UClassID getDynamicClassID() const;
sl@0: 
sl@0: public:
sl@0: #ifdef SERVICE_DEBUG
sl@0:     virtual UnicodeString& debug(UnicodeString& result) const {
sl@0:       return debugClass(result);
sl@0:     }
sl@0: 
sl@0:     virtual UnicodeString& debugClass(UnicodeString& result) const {
sl@0:       return result.append("Key");
sl@0:     }
sl@0: #endif
sl@0: };
sl@0: 
sl@0: /**
sl@0:  * <p>Abstract implementation of a notification facility.  Clients add
sl@0:  * EventListeners with addListener and remove them with removeListener.
sl@0:  * Notifiers call notifyChanged when they wish to notify listeners.
sl@0:  * This queues the listener list on the notification thread, which
sl@0:  * eventually dequeues the list and calls notifyListener on each
sl@0:  * listener in the list.</p>
sl@0:  *
sl@0:  * <p>Subclasses override acceptsListener and notifyListener 
sl@0:  * to add type-safe notification.  AcceptsListener should return
sl@0:  * true if the listener is of the appropriate type; ICUNotifier
sl@0:  * itself will ensure the listener is non-null and that the
sl@0:  * identical listener is not already registered with the Notifier.
sl@0:  * NotifyListener should cast the listener to the appropriate 
sl@0:  * type and call the appropriate method on the listener.
sl@0:  */
sl@0: 
sl@0: class U_COMMON_API ICUNotifier : public UMemory  {
sl@0: private: UMTX notifyLock;
sl@0: private: UVector* listeners;
sl@0:          
sl@0: public: 
sl@0:     ICUNotifier(void);
sl@0:     
sl@0:     virtual ~ICUNotifier(void);
sl@0:     
sl@0:     /**
sl@0:      * Add a listener to be notified when notifyChanged is called.
sl@0:      * The listener must not be null. AcceptsListener must return
sl@0:      * true for the listener.  Attempts to concurrently
sl@0:      * register the identical listener more than once will be
sl@0:      * silently ignored.  
sl@0:      */
sl@0:     virtual void addListener(const EventListener* l, UErrorCode& status);
sl@0:     
sl@0:     /**
sl@0:      * Stop notifying this listener.  The listener must
sl@0:      * not be null.  Attemps to remove a listener that is
sl@0:      * not registered will be silently ignored.
sl@0:      */
sl@0:     virtual void removeListener(const EventListener* l, UErrorCode& status);
sl@0:     
sl@0:     /**
sl@0:      * ICU doesn't spawn its own threads.  All listeners are notified in
sl@0:      * the thread of the caller.  Misbehaved listeners can therefore
sl@0:      * indefinitely block the calling thread.  Callers should beware of
sl@0:      * deadlock situations.  
sl@0:      */
sl@0:     virtual void notifyChanged(void);
sl@0:     
sl@0: protected: 
sl@0:     /**
sl@0:      * Subclasses implement this to return TRUE if the listener is
sl@0:      * of the appropriate type.
sl@0:      */
sl@0:     virtual UBool acceptsListener(const EventListener& l) const = 0;
sl@0:     
sl@0:     /**
sl@0:      * Subclasses implement this to notify the listener.
sl@0:      */
sl@0:     virtual void notifyListener(EventListener& l) const = 0;
sl@0: };
sl@0: 
sl@0: U_NAMESPACE_END
sl@0: 
sl@0: /* UCONFIG_NO_SERVICE */
sl@0: #endif
sl@0: 
sl@0: /* ICUNOTIF_H */
sl@0: #endif