icuSources/common/servnotf.h

   1 /**
   2  *******************************************************************************
   3  * Copyright (C) 2001-2004, International Business Machines Corporation and    *
   4  * others. All Rights Reserved.                                                *
   5  *******************************************************************************
   6  */
   7 #ifndef ICUNOTIF_H
   8 #define ICUNOTIF_H
   9
  10 #include "unicode/utypes.h"
  11
  12 #if UCONFIG_NO_SERVICE
  13
  14 U_NAMESPACE_BEGIN
  15
  16 /*
  17  * Allow the declaration of APIs with pointers to BreakIterator
  18  * even when break iteration is removed from the build.
  19  */
  20 class ICUNotifier;
  21
  22 U_NAMESPACE_END
  23
  24 #else
  25
  26 #include "unicode/uobject.h"
  27 #include "unicode/unistr.h"
  28
  29 #include "mutex.h"
  30 #include "uvector.h"
  31
  32 U_NAMESPACE_BEGIN
  33
  34 class U_COMMON_API EventListener : public UObject {
  35 public:
  36     virtual ~EventListener();
  37
  38 public:
  39     static UClassID U_EXPORT2 getStaticClassID();
  40
  41     virtual UClassID getDynamicClassID() const;
  42
  43 public:
  44 #ifdef SERVICE_DEBUG
  45     virtual UnicodeString& debug(UnicodeString& result) const {
  46       return debugClass(result);
  47     }
  48
  49     virtual UnicodeString& debugClass(UnicodeString& result) const {
  50       return result.append("Key");
  51     }
  52 #endif
  53 };
  54
  55 /**
  56  * <p>Abstract implementation of a notification facility.  Clients add
  57  * EventListeners with addListener and remove them with removeListener.
  58  * Notifiers call notifyChanged when they wish to notify listeners.
  59  * This queues the listener list on the notification thread, which
  60  * eventually dequeues the list and calls notifyListener on each
  61  * listener in the list.</p>
  62  *
  63  * <p>Subclasses override acceptsListener and notifyListener
  64  * to add type-safe notification.  AcceptsListener should return
  65  * true if the listener is of the appropriate type; ICUNotifier
  66  * itself will ensure the listener is non-null and that the
  67  * identical listener is not already registered with the Notifier.
  68  * NotifyListener should cast the listener to the appropriate
  69  * type and call the appropriate method on the listener.
  70  */
  71
  72 class U_COMMON_API ICUNotifier : public UMemory  {
  73 private: UMTX notifyLock;
  74 private: UVector* listeners;
  75
  76 public:
  77     ICUNotifier(void);
  78
  79     virtual ~ICUNotifier(void);
  80
  81     /**
  82      * Add a listener to be notified when notifyChanged is called.
  83      * The listener must not be null. AcceptsListener must return
  84      * true for the listener.  Attempts to concurrently
  85      * register the identical listener more than once will be
  86      * silently ignored.
  87      */
  88     virtual void addListener(const EventListener* l, UErrorCode& status);
  89
  90     /**
  91      * Stop notifying this listener.  The listener must
  92      * not be null.  Attemps to remove a listener that is
  93      * not registered will be silently ignored.
  94      */
  95     virtual void removeListener(const EventListener* l, UErrorCode& status);
  96
  97     /**
  98      * ICU doesn't spawn its own threads.  All listeners are notified in
  99      * the thread of the caller.  Misbehaved listeners can therefore
 100      * indefinitely block the calling thread.  Callers should beware of
 101      * deadlock situations.
 102      */
 103     virtual void notifyChanged(void);
 104
 105 protected:
 106     /**
 107      * Subclasses implement this to return TRUE if the listener is
 108      * of the appropriate type.
 109      */
 110     virtual UBool acceptsListener(const EventListener& l) const = 0;
 111
 112     /**
 113      * Subclasses implement this to notify the listener.
 114      */
 115     virtual void notifyListener(EventListener& l) const = 0;
 116 };
 117
 118 U_NAMESPACE_END
 119
 120 /* UCONFIG_NO_SERVICE */
 121 #endif
 122
 123 /* ICUNOTIF_H */
 124 #endif