michael@0: /**
michael@0:  *******************************************************************************
michael@0:  * Copyright (C) 2001-2011, International Business Machines Corporation and    *
michael@0:  * others. All Rights Reserved.                                                *
michael@0:  *******************************************************************************
michael@0:  */
michael@0: #ifndef ICUNOTIF_H
michael@0: #define ICUNOTIF_H
michael@0: 
michael@0: #include "unicode/utypes.h"
michael@0: 
michael@0: #if UCONFIG_NO_SERVICE
michael@0: 
michael@0: U_NAMESPACE_BEGIN
michael@0: 
michael@0: /*
michael@0:  * Allow the declaration of APIs with pointers to BreakIterator
michael@0:  * even when break iteration is removed from the build.
michael@0:  */
michael@0: class ICUNotifier;
michael@0: 
michael@0: U_NAMESPACE_END
michael@0: 
michael@0: #else
michael@0: 
michael@0: #include "unicode/uobject.h"
michael@0: #include "unicode/unistr.h"
michael@0: 
michael@0: #include "mutex.h"
michael@0: #include "uvector.h"
michael@0: 
michael@0: U_NAMESPACE_BEGIN
michael@0: 
michael@0: class U_COMMON_API EventListener : public UObject {
michael@0: public: 
michael@0:     virtual ~EventListener();
michael@0: 
michael@0: public:
michael@0:     static UClassID U_EXPORT2 getStaticClassID();
michael@0: 
michael@0:     virtual UClassID getDynamicClassID() const;
michael@0: 
michael@0: public:
michael@0: #ifdef SERVICE_DEBUG
michael@0:     virtual UnicodeString& debug(UnicodeString& result) const {
michael@0:       return debugClass(result);
michael@0:     }
michael@0: 
michael@0:     virtual UnicodeString& debugClass(UnicodeString& result) const {
michael@0:       return result.append("Key");
michael@0:     }
michael@0: #endif
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * <p>Abstract implementation of a notification facility.  Clients add
michael@0:  * EventListeners with addListener and remove them with removeListener.
michael@0:  * Notifiers call notifyChanged when they wish to notify listeners.
michael@0:  * This queues the listener list on the notification thread, which
michael@0:  * eventually dequeues the list and calls notifyListener on each
michael@0:  * listener in the list.</p>
michael@0:  *
michael@0:  * <p>Subclasses override acceptsListener and notifyListener 
michael@0:  * to add type-safe notification.  AcceptsListener should return
michael@0:  * true if the listener is of the appropriate type; ICUNotifier
michael@0:  * itself will ensure the listener is non-null and that the
michael@0:  * identical listener is not already registered with the Notifier.
michael@0:  * NotifyListener should cast the listener to the appropriate 
michael@0:  * type and call the appropriate method on the listener.
michael@0:  */
michael@0: 
michael@0: class U_COMMON_API ICUNotifier : public UMemory  {
michael@0: private: UVector* listeners;
michael@0:          
michael@0: public: 
michael@0:     ICUNotifier(void);
michael@0:     
michael@0:     virtual ~ICUNotifier(void);
michael@0:     
michael@0:     /**
michael@0:      * Add a listener to be notified when notifyChanged is called.
michael@0:      * The listener must not be null. AcceptsListener must return
michael@0:      * true for the listener.  Attempts to concurrently
michael@0:      * register the identical listener more than once will be
michael@0:      * silently ignored.  
michael@0:      */
michael@0:     virtual void addListener(const EventListener* l, UErrorCode& status);
michael@0:     
michael@0:     /**
michael@0:      * Stop notifying this listener.  The listener must
michael@0:      * not be null.  Attemps to remove a listener that is
michael@0:      * not registered will be silently ignored.
michael@0:      */
michael@0:     virtual void removeListener(const EventListener* l, UErrorCode& status);
michael@0:     
michael@0:     /**
michael@0:      * ICU doesn't spawn its own threads.  All listeners are notified in
michael@0:      * the thread of the caller.  Misbehaved listeners can therefore
michael@0:      * indefinitely block the calling thread.  Callers should beware of
michael@0:      * deadlock situations.  
michael@0:      */
michael@0:     virtual void notifyChanged(void);
michael@0:     
michael@0: protected: 
michael@0:     /**
michael@0:      * Subclasses implement this to return TRUE if the listener is
michael@0:      * of the appropriate type.
michael@0:      */
michael@0:     virtual UBool acceptsListener(const EventListener& l) const = 0;
michael@0:     
michael@0:     /**
michael@0:      * Subclasses implement this to notify the listener.
michael@0:      */
michael@0:     virtual void notifyListener(EventListener& l) const = 0;
michael@0: };
michael@0: 
michael@0: U_NAMESPACE_END
michael@0: 
michael@0: /* UCONFIG_NO_SERVICE */
michael@0: #endif
michael@0: 
michael@0: /* ICUNOTIF_H */
michael@0: #endif