// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/**
*******************************************************************************
* Copyright (C) 2001-2011, International Business Machines Corporation. *
* All Rights Reserved. *
*******************************************************************************
*/
#ifndef ICUSERV_H
#define ICUSERV_H
#include "unicode/utypes.h"
#if UCONFIG_NO_SERVICE
U_NAMESPACE_BEGIN
/*
* Allow the declaration of APIs with pointers to ICUService
* even when service is removed from the build.
*/
class ICUService;
U_NAMESPACE_END
#else
#include "unicode/unistr.h"
#include "unicode/locid.h"
#include "unicode/umisc.h"
#include "hash.h"
#include "uvector.h"
#include "servnotf.h"
class ICUServiceTest;
U_NAMESPACE_BEGIN
class ICUServiceKey;
class ICUServiceFactory;
class SimpleFactory;
class ServiceListener;
class ICUService;
class DNCache;
/*******************************************************************
* ICUServiceKey
*/
/**
* <p>ICUServiceKeys are used to communicate with factories to
* generate an instance of the service. ICUServiceKeys define how
* ids are canonicalized, provide both a current id and a current
* descriptor to use in querying the cache and factories, and
* determine the fallback strategy.</p>
*
* <p>ICUServiceKeys provide both a currentDescriptor and a currentID.
* The descriptor contains an optional prefix, followed by '/'
* and the currentID. Factories that handle complex keys,
* for example number format factories that generate multiple
* kinds of formatters for the same locale, use the descriptor
* to provide a fully unique identifier for the service object,
* while using the currentID (in this case, the locale string),
* as the visible IDs that can be localized.</p>
*
* <p>The default implementation of ICUServiceKey has no fallbacks and
* has no custom descriptors.</p>
*/
class U_COMMON_API ICUServiceKey : public UObject {
private:
const UnicodeString _id;
protected:
static const char16_t PREFIX_DELIMITER;
public:
/**
* <p>Construct a key from an id.</p>
*
* @param id the ID from which to construct the key.
*/
ICUServiceKey(const UnicodeString& id);
/**
* <p>Virtual destructor.</p>
*/
virtual ~ICUServiceKey();
/**
* <p>Return the original ID used to construct this key.</p>
*
* @return the ID used to construct this key.
*/
virtual const UnicodeString& getID() const;
/**
* <p>Return the canonical version of the original ID. This implementation
* appends the original ID to result. Result is returned as a convenience.</p>
*
* @param result the output parameter to which the id will be appended.
* @return the modified result.
*/
virtual UnicodeString& canonicalID(UnicodeString& result) const;
/**
* <p>Return the (canonical) current ID. This implementation appends
* the canonical ID to result. Result is returned as a convenience.</p>
*
* @param result the output parameter to which the current id will be appended.
* @return the modified result.
*/
virtual UnicodeString& currentID(UnicodeString& result) const;
/**
* <p>Return the current descriptor. This implementation appends
* the current descriptor to result. Result is returned as a convenience.</p>
*
* <p>The current descriptor is used to fully
* identify an instance of the service in the cache. A
* factory may handle all descriptors for an ID, or just a
* particular descriptor. The factory can either parse the
* descriptor or use custom API on the key in order to
* instantiate the service.</p>
*
* @param result the output parameter to which the current id will be appended.
* @return the modified result.
*/
virtual UnicodeString& currentDescriptor(UnicodeString& result) const;
/**
* <p>If the key has a fallback, modify the key and return true,
* otherwise return false. The current ID will change if there
* is a fallback. No currentIDs should be repeated, and fallback
* must eventually return false. This implementation has no fallbacks
* and always returns false.</p>
*
* @return true if the ICUServiceKey changed to a valid fallback value.
*/
virtual UBool fallback();
/**
* <p>Return true if a key created from id matches, or would eventually
* fallback to match, the canonical ID of this ICUServiceKey.</p>
*
* @param id the id to test.
* @return true if this ICUServiceKey's canonical ID is a fallback of id.
*/
virtual UBool isFallbackOf(const UnicodeString& id) const;
/**
* <p>Return the prefix. This implementation leaves result unchanged.
* Result is returned as a convenience.</p>
*
* @param result the output parameter to which the prefix will be appended.
* @return the modified result.
*/
virtual UnicodeString& prefix(UnicodeString& result) const;
/**
* <p>A utility to parse the prefix out of a descriptor string. Only
* the (undelimited) prefix, if any, remains in result. Result is returned as a
* convenience.</p>
*
* @param result an input/output parameter that on entry is a descriptor, and
* on exit is the prefix of that descriptor.
* @return the modified result.
*/
static UnicodeString& parsePrefix(UnicodeString& result);
/**
* <p>A utility to parse the suffix out of a descriptor string. Only
* the (undelimited) suffix, if any, remains in result. Result is returned as a
* convenience.</p>
*
* @param result an input/output parameter that on entry is a descriptor, and
* on exit is the suffix of that descriptor.
* @return the modified result.
*/
static UnicodeString& parseSuffix(UnicodeString& result);
public:
/**
* UObject RTTI boilerplate.
*/
static UClassID U_EXPORT2 getStaticClassID();
/**
* UObject RTTI boilerplate.
*/
virtual UClassID getDynamicClassID() const override;
#ifdef SERVICE_DEBUG
public:
virtual UnicodeString& debug(UnicodeString& result) const;
virtual UnicodeString& debugClass(UnicodeString& result) const;
#endif
};
/*******************************************************************
* ICUServiceFactory
*/
/**
* <p>An implementing ICUServiceFactory generates the service objects maintained by the
* service. A factory generates a service object from a key,
* updates id->factory mappings, and returns the display name for
* a supported id.</p>
*/
class U_COMMON_API ICUServiceFactory : public UObject {
public:
virtual ~ICUServiceFactory();
/**
* <p>Create a service object from the key, if this factory
* supports the key. Otherwise, return nullptr.</p>
*
* <p>If the factory supports the key, then it can call
* the service's getKey(ICUServiceKey, String[], ICUServiceFactory) method
* passing itself as the factory to get the object that
* the service would have created prior to the factory's
* registration with the service. This can change the
* key, so any information required from the key should
* be extracted before making such a callback.</p>
*
* @param key the service key.
* @param service the service with which this factory is registered.
* @param status the error code status.
* @return the service object, or nullptr if the factory does not support the key.
*/
virtual UObject* create(const ICUServiceKey& key, const ICUService* service, UErrorCode& status) const = 0;
/**
* <p>Update result to reflect the IDs (not descriptors) that this
* factory publicly handles. Result contains mappings from ID to
* factory. On entry it will contain all (visible) mappings from
* previously-registered factories.</p>
*
* <p>This function, together with getDisplayName, are used to
* support ICUService::getDisplayNames. The factory determines
* which IDs (of those it supports) it will make visible, and of
* those, which it will provide localized display names for. In
* most cases it will register mappings from all IDs it supports
* to itself.</p>
*
* @param result the mapping table to update.
* @param status the error code status.
*/
virtual void updateVisibleIDs(Hashtable& result, UErrorCode& status) const = 0;
/**
* <p>Return, in result, the display name of the id in the provided locale.
* This is an id, not a descriptor. If the id is
* not visible, sets result to bogus. If the
* incoming result is bogus, it remains bogus. Result is returned as a
* convenience. Results are not defined if id is not one supported by this
* factory.</p>
*
* @param id a visible id supported by this factory.
* @param locale the locale for which to generate the corresponding localized display name.
* @param result output parameter to hold the display name.
* @return result.
*/
virtual UnicodeString& getDisplayName(const UnicodeString& id, const Locale& locale, UnicodeString& result) const = 0;
};
/*
******************************************************************
*/
/**
* <p>A default implementation of factory. This provides default
* implementations for subclasses, and implements a singleton
* factory that matches a single ID and returns a single
* (possibly deferred-initialized) instance. This implements
* updateVisibleIDs to add a mapping from its ID to itself
* if visible is true, or to remove any existing mapping
* for its ID if visible is false. No localization of display
* names is performed.</p>
*/
class U_COMMON_API SimpleFactory : public ICUServiceFactory {
protected:
UObject* _instance;
const UnicodeString _id;
const UBool _visible;
public:
/**
* <p>Construct a SimpleFactory that maps a single ID to a single
* service instance. If visible is true, the ID will be visible.
* The instance must not be nullptr. The SimpleFactory will adopt
* the instance, which must not be changed subsequent to this call.</p>
*
* @param instanceToAdopt the service instance to adopt.
* @param id the ID to assign to this service instance.
* @param visible if true, the ID will be visible.
*/
SimpleFactory(UObject* instanceToAdopt, const UnicodeString& id, UBool visible = true);
/**
* <p>Destructor.</p>
*/
virtual ~SimpleFactory();
/**
* <p>This implementation returns a clone of the service instance if the factory's ID is equal to
* the key's currentID. Service and prefix are ignored.</p>
*
* @param key the service key.
* @param service the service with which this factory is registered.
* @param status the error code status.
* @return the service object, or nullptr if the factory does not support the key.
*/
virtual UObject* create(const ICUServiceKey& key, const ICUService* service, UErrorCode& status) const override;
/**
* <p>This implementation adds a mapping from ID -> this to result if visible is true,
* otherwise it removes ID from result.</p>
*
* @param result the mapping table to update.
* @param status the error code status.
*/
virtual void updateVisibleIDs(Hashtable& result, UErrorCode& status) const override;
/**
* <p>This implementation returns the factory ID if it equals id and visible is true,
* otherwise it returns the empty string. (This implementation provides
* no localized id information.)</p>
*
* @param id a visible id supported by this factory.
* @param locale the locale for which to generate the corresponding localized display name.
* @param result output parameter to hold the display name.
* @return result.
*/
virtual UnicodeString& getDisplayName(const UnicodeString& id, const Locale& locale, UnicodeString& result) const override;
public:
/**
* UObject RTTI boilerplate.
*/
static UClassID U_EXPORT2 getStaticClassID();
/**
* UObject RTTI boilerplate.
*/
virtual UClassID getDynamicClassID() const override;
#ifdef SERVICE_DEBUG
public:
virtual UnicodeString& debug(UnicodeString& toAppendTo) const;
virtual UnicodeString& debugClass(UnicodeString& toAppendTo) const;
#endif
};
/*
******************************************************************
*/
/**
* <p>ServiceListener is the listener that ICUService provides by default.
* ICUService will notify this listener when factories are added to
* or removed from the service. Subclasses can provide
* different listener interfaces that extend EventListener, and modify
* acceptsListener and notifyListener as appropriate.</p>
*/
class U_COMMON_API ServiceListener : public EventListener {
public:
virtual ~ServiceListener();
/**
* <p>This method is called when the service changes. At the time of the
* call this listener is registered with the service. It must
* not modify the notifier in the context of this call.</p>
*
* @param service the service that changed.
*/
virtual void serviceChanged(const ICUService& service) const = 0;
public:
/**
* UObject RTTI boilerplate.
*/
static UClassID U_EXPORT2 getStaticClassID();
/**
* UObject RTTI boilerplate.
*/
virtual UClassID getDynamicClassID() const override;
};
/*
******************************************************************
*/
/**
* <p>A StringPair holds a displayName/ID pair. ICUService uses it
* as the array elements returned by getDisplayNames.
*/
class U_COMMON_API StringPair : public UMemory {
public:
/**
* <p>The display name of the pair.</p>
*/
const UnicodeString displayName;
/**
* <p>The ID of the pair.</p>
*/
const UnicodeString id;
/**
* <p>Creates a string pair from a displayName and an ID.</p>
*
* @param displayName the displayName.
* @param id the ID.
* @param status the error code status.
* @return a StringPair if the creation was successful, otherwise nullptr.
*/
static StringPair* create(const UnicodeString& displayName,
const UnicodeString& id,
UErrorCode& status);
/**
* <p>Return true if either string of the pair is bogus.</p>
* @return true if either string of the pair is bogus.
*/
UBool isBogus() const;
private:
StringPair(const UnicodeString& displayName, const UnicodeString& id);
};
/*******************************************************************
* ICUService
*/
/**
* <p>A Service provides access to service objects that implement a
* particular service, e.g. transliterators. Users provide a String
* id (for example, a locale string) to the service, and get back an
* object for that id. Service objects can be any kind of object. A
* new service object is returned for each query. The caller is
* responsible for deleting it.</p>
*
* <p>Services 'canonicalize' the query ID and use the canonical ID to
* query for the service. The service also defines a mechanism to
* 'fallback' the ID multiple times. Clients can optionally request
* the actual ID that was matched by a query when they use an ID to
* retrieve a service object.</p>
*
* <p>Service objects are instantiated by ICUServiceFactory objects
* registered with the service. The service queries each
* ICUServiceFactory in turn, from most recently registered to
* earliest registered, until one returns a service object. If none
* responds with a service object, a fallback ID is generated, and the
* process repeats until a service object is returned or until the ID
* has no further fallbacks.</p>
*
* <p>In ICU 2.4, UObject (the base class of service instances) does
* not define a polymorphic clone function. ICUService uses clones to
* manage ownership. Thus, for now, ICUService defines an abstract
* method, cloneInstance, that clients must implement to create clones
* of the service instances. This may change in future releases of
* ICU.</p>
*
* <p>ICUServiceFactories can be dynamically registered and
* unregistered with the service. When registered, an
* ICUServiceFactory is installed at the head of the factory list, and
* so gets 'first crack' at any keys or fallback keys. When
* unregistered, it is removed from the service and can no longer be
* located through it. Service objects generated by this factory and
* held by the client are unaffected.</p>
*
* <p>If a service has variants (e.g., the different variants of
* BreakIterator) an ICUServiceFactory can use the prefix of the
* ICUServiceKey to determine the variant of a service to generate.
* If it does not support all variants, it can request
* previously-registered factories to handle the ones it does not
* support.</p>
*
* <p>ICUService uses ICUServiceKeys to query factories and perform
* fallback. The ICUServiceKey defines the canonical form of the ID,
* and implements the fallback strategy. Custom ICUServiceKeys can be
* defined that parse complex IDs into components that
* ICUServiceFactories can more easily use. The ICUServiceKey can
* cache the results of this parsing to save repeated effort.
* ICUService provides convenience APIs that take UnicodeStrings and
* generate default ICUServiceKeys for use in querying.</p>
*
* <p>ICUService provides API to get the list of IDs publicly
* supported by the service (although queries aren't restricted to
* this list). This list contains only 'simple' IDs, and not fully
* unique IDs. ICUServiceFactories are associated with each simple ID
* and the responsible factory can also return a human-readable
* localized version of the simple ID, for use in user interfaces.
* ICUService can also provide an array of the all the localized
* visible IDs and their corresponding internal IDs.</p>
*
* <p>ICUService implements ICUNotifier, so that clients can register
* to receive notification when factories are added or removed from
* the service. ICUService provides a default EventListener
* subinterface, ServiceListener, which can be registered with the
* service. When the service changes, the ServiceListener's
* serviceChanged method is called with the service as the
* argument.</p>
*
* <p>The ICUService API is both rich and generic, and it is expected
* that most implementations will statically 'wrap' ICUService to
* present a more appropriate API-- for example, to declare the type
* of the objects returned from get, to limit the factories that can
* be registered with the service, or to define their own listener
* interface with a custom callback method. They might also customize
* ICUService by overriding it, for example, to customize the
* ICUServiceKey and fallback strategy. ICULocaleService is a
* subclass of ICUService that uses Locale names as IDs and uses
* ICUServiceKeys that implement the standard resource bundle fallback
* strategy. Most clients will wish to subclass it instead of
* ICUService.</p>
*/
class U_COMMON_API ICUService : public ICUNotifier {
protected:
/**
* Name useful for debugging.
*/
const UnicodeString name;
private:
/**
* Timestamp so iterators can be fail-fast.
*/
uint32_t timestamp;
/**
* All the factories registered with this service.
*/
UVector* factories;
/**
* The service cache.
*/
Hashtable* serviceCache;
/**
* The ID cache.
*/
Hashtable* idCache;
/**
* The name cache.
*/
DNCache* dnCache;
/**
* Constructor.
*/
public:
/**
* <p>Construct a new ICUService.</p>
*/
ICUService();
/**
* <p>Construct with a name (useful for debugging).</p>
*
* @param name a name to use in debugging.
*/
ICUService(const UnicodeString& name);
/**
* <p>Destructor.</p>
*/
virtual ~ICUService();
/**
* <p>Return the name of this service. This will be the empty string if none was assigned.
* Returns result as a convenience.</p>
*
* @param result an output parameter to contain the name of this service.
* @return the name of this service.
*/
UnicodeString& getName(UnicodeString& result) const;
/**
* <p>Convenience override for get(ICUServiceKey&, UnicodeString*). This uses
* createKey to create a key for the provided descriptor.</p>
*
* @param descriptor the descriptor.
* @param status the error code status.
* @return the service instance, or nullptr.
*/
UObject* get(const UnicodeString& descriptor, UErrorCode& status) const;
/**
* <p>Convenience override for get(ICUServiceKey&, UnicodeString*). This uses
* createKey to create a key from the provided descriptor.</p>
*
* @param descriptor the descriptor.
* @param actualReturn a pointer to a UnicodeString to hold the matched descriptor, or nullptr.
* @param status the error code status.
* @return the service instance, or nullptr.
*/
UObject* get(const UnicodeString& descriptor, UnicodeString* actualReturn, UErrorCode& status) const;
/**
* <p>Convenience override for get(ICUServiceKey&, UnicodeString*).</p>
*
* @param key the key.
* @param status the error code status.
* @return the service instance, or nullptr.
*/
UObject* getKey(ICUServiceKey& key, UErrorCode& status) const;
/**
* <p>Given a key, return a service object, and, if actualReturn
* is not nullptr, the descriptor with which it was found in the
* first element of actualReturn. If no service object matches
* this key, returns nullptr and leaves actualReturn unchanged.</p>
*
* <p>This queries the cache using the key's descriptor, and if no
* object in the cache matches, tries the key on each
* registered factory, in order. If none generates a service
* object for the key, repeats the process with each fallback of
* the key, until either a factory returns a service object, or the key
* has no fallback. If no object is found, the result of handleDefault
* is returned.</p>
*
* <p>Subclasses can override this method to further customize the
* result before returning it.
*
* @param key the key.
* @param actualReturn a pointer to a UnicodeString to hold the matched descriptor, or nullptr.
* @param status the error code status.
* @return the service instance, or nullptr.
*/
virtual UObject* getKey(ICUServiceKey& key, UnicodeString* actualReturn, UErrorCode& status) const;
/**
* <p>This version of getKey is only called by ICUServiceFactories within the scope
* of a previous getKey call, to determine what previously-registered factories would
* have returned. For details, see getKey(ICUServiceKey&, UErrorCode&). Subclasses
* should not call it directly, but call through one of the other get functions.</p>
*
* @param key the key.
* @param actualReturn a pointer to a UnicodeString to hold the matched descriptor, or nullptr.
* @param factory the factory making the recursive call.
* @param status the error code status.
* @return the service instance, or nullptr.
*/
UObject* getKey(ICUServiceKey& key, UnicodeString* actualReturn, const ICUServiceFactory* factory, UErrorCode& status) const;
/**
* <p>Convenience override for getVisibleIDs(String) that passes null
* as the fallback, thus returning all visible IDs.</p>
*
* @param result a vector to hold the returned IDs.
* @param status the error code status.
* @return the result vector.
*/
UVector& getVisibleIDs(UVector& result, UErrorCode& status) const;
/**
* <p>Return a snapshot of the visible IDs for this service. This
* list will not change as ICUServiceFactories are added or removed, but the
* supported IDs will, so there is no guarantee that all and only
* the IDs in the returned list will be visible and supported by the
* service in subsequent calls.</p>
*
* <p>The IDs are returned as pointers to UnicodeStrings. The
* caller owns the IDs. Previous contents of result are discarded before
* new elements, if any, are added.</p>
*
* <p>matchID is passed to createKey to create a key. If the key
* is not nullptr, its isFallbackOf method is used to filter out IDs
* that don't match the key or have it as a fallback.</p>
*
* @param result a vector to hold the returned IDs.
* @param matchID an ID used to filter the result, or nullptr if all IDs are desired.
* @param status the error code status.
* @return the result vector.
*/
UVector& getVisibleIDs(UVector& result, const UnicodeString* matchID, UErrorCode& status) const;
/**
* <p>Convenience override for getDisplayName(const UnicodeString&, const Locale&, UnicodeString&) that
* uses the current default locale.</p>
*
* @param id the ID for which to retrieve the localized displayName.
* @param result an output parameter to hold the display name.
* @return the modified result.
*/
UnicodeString& getDisplayName(const UnicodeString& id, UnicodeString& result) const;
/**
* <p>Given a visible ID, return the display name in the requested locale.
* If there is no directly supported ID corresponding to this ID, result is
* set to bogus.</p>
*
* @param id the ID for which to retrieve the localized displayName.
* @param result an output parameter to hold the display name.
* @param locale the locale in which to localize the ID.
* @return the modified result.
*/
UnicodeString& getDisplayName(const UnicodeString& id, UnicodeString& result, const Locale& locale) const;
/**
* <p>Convenience override of getDisplayNames(const Locale&, const UnicodeString*) that
* uses the current default Locale as the locale and nullptr for
* the matchID.</p>
*
* @param result a vector to hold the returned displayName/id StringPairs.
* @param status the error code status.
* @return the modified result vector.
*/
UVector& getDisplayNames(UVector& result, UErrorCode& status) const;
/**
* <p>Convenience override of getDisplayNames(const Locale&, const UnicodeString*) that
* uses nullptr for the matchID.</p>
*
* @param result a vector to hold the returned displayName/id StringPairs.
* @param locale the locale in which to localize the ID.
* @param status the error code status.
* @return the modified result vector.
*/
UVector& getDisplayNames(UVector& result, const Locale& locale, UErrorCode& status) const;
/**
* <p>Return a snapshot of the mapping from display names to visible
* IDs for this service. This set will not change as factories
* are added or removed, but the supported IDs will, so there is
* no guarantee that all and only the IDs in the returned map will
* be visible and supported by the service in subsequent calls,
* nor is there any guarantee that the current display names match
* those in the result.</p>
*
* <p>The names are returned as pointers to StringPairs, which
* contain both the displayName and the corresponding ID. The
* caller owns the StringPairs. Previous contents of result are
* discarded before new elements, if any, are added.</p>
*
* <p>matchID is passed to createKey to create a key. If the key
* is not nullptr, its isFallbackOf method is used to filter out IDs
* that don't match the key or have it as a fallback.</p>
*
* @param result a vector to hold the returned displayName/id StringPairs.
* @param locale the locale in which to localize the ID.
* @param matchID an ID used to filter the result, or nullptr if all IDs are desired.
* @param status the error code status.
* @return the result vector. */
UVector& getDisplayNames(UVector& result,
const Locale& locale,
const UnicodeString* matchID,
UErrorCode& status) const;
/**
* <p>A convenience override of registerInstance(UObject*, const UnicodeString&, UBool)
* that defaults visible to true.</p>
*
* @param objToAdopt the object to register and adopt.
* @param id the ID to assign to this object.
* @param status the error code status.
* @return a registry key that can be passed to unregister to unregister
* (and discard) this instance.
*/
URegistryKey registerInstance(UObject* objToAdopt, const UnicodeString& id, UErrorCode& status);
/**
* <p>Register a service instance with the provided ID. The ID will be
* canonicalized. The canonicalized ID will be returned by
* getVisibleIDs if visible is true. The service instance will be adopted and
* must not be modified subsequent to this call.</p>
*
* <p>This issues a serviceChanged notification to registered listeners.</p>
*
* <p>This implementation wraps the object using
* createSimpleFactory, and calls registerFactory.</p>
*
* @param objToAdopt the object to register and adopt.
* @param id the ID to assign to this object.
* @param visible true if getVisibleIDs is to return this ID.
* @param status the error code status.
* @return a registry key that can be passed to unregister() to unregister
* (and discard) this instance.
*/
virtual URegistryKey registerInstance(UObject* objToAdopt, const UnicodeString& id, UBool visible, UErrorCode& status);
/**
* <p>Register an ICUServiceFactory. Returns a registry key that
* can be used to unregister the factory. The factory
* must not be modified subsequent to this call. The service owns
* all registered factories. In case of an error, the factory is
* deleted.</p>
*
* <p>This issues a serviceChanged notification to registered listeners.</p>
*
* <p>The default implementation accepts all factories.</p>
*
* @param factoryToAdopt the factory to register and adopt.
* @param status the error code status.
* @return a registry key that can be passed to unregister to unregister
* (and discard) this factory.
*/
virtual URegistryKey registerFactory(ICUServiceFactory* factoryToAdopt, UErrorCode& status);
/**
* <p>Unregister a factory using a registry key returned by
* registerInstance or registerFactory. After a successful call,
* the factory will be removed from the service factory list and
* deleted, and the key becomes invalid.</p>
*
* <p>This issues a serviceChanged notification to registered
* listeners.</p>
*
* @param rkey the registry key.
* @param status the error code status.
* @return true if the call successfully unregistered the factory.
*/
virtual UBool unregister(URegistryKey rkey, UErrorCode& status);
/**
* </p>Reset the service to the default factories. The factory
* lock is acquired and then reInitializeFactories is called.</p>
*
* <p>This issues a serviceChanged notification to registered listeners.</p>
*/
virtual void reset();
/**
* <p>Return true if the service is in its default state.</p>
*
* <p>The default implementation returns true if there are no
* factories registered.</p>
*/
virtual UBool isDefault() const;
/**
* <p>Create a key from an ID. If ID is nullptr, returns nullptr.</p>
*
* <p>The default implementation creates an ICUServiceKey instance.
* Subclasses can override to define more useful keys appropriate
* to the factories they accept.</p>
*
* @param a pointer to the ID for which to create a default ICUServiceKey.
* @param status the error code status.
* @return the ICUServiceKey corresponding to ID, or nullptr.
*/
virtual ICUServiceKey* createKey(const UnicodeString* id, UErrorCode& status) const;
/**
* <p>Clone object so that caller can own the copy. In ICU2.4, UObject doesn't define
* clone, so we need an instance-aware method that knows how to do this.
* This is public so factories can call it, but should really be protected.</p>
*
* @param instance the service instance to clone.
* @return a clone of the passed-in instance, or nullptr if cloning was unsuccessful.
*/
virtual UObject* cloneInstance(UObject* instance) const = 0;
/************************************************************************
* Subclassing API
*/
protected:
/**
* <p>Create a factory that wraps a single service object. Called by registerInstance.</p>
*
* <p>The default implementation returns an instance of SimpleFactory.</p>
*
* @param instanceToAdopt the service instance to adopt.
* @param id the ID to assign to this service instance.
* @param visible if true, the ID will be visible.
* @param status the error code status.
* @return an instance of ICUServiceFactory that maps this instance to the provided ID.
*/
virtual ICUServiceFactory* createSimpleFactory(UObject* instanceToAdopt, const UnicodeString& id, UBool visible, UErrorCode& status);
/**
* <p>Reinitialize the factory list to its default state. After this call, isDefault()
* must return true.</p>
*
* <p>This issues a serviceChanged notification to registered listeners.</p>
*
* <p>The default implementation clears the factory list.
* Subclasses can override to provide other default initialization
* of the factory list. Subclasses must not call this method
* directly, since it must only be called while holding write
* access to the factory list.</p>
*/
virtual void reInitializeFactories();
/**
* <p>Default handler for this service if no factory in the factory list
* handled the key passed to getKey.</p>
*
* <p>The default implementation returns nullptr.</p>
*
* @param key the key.
* @param actualReturn a pointer to a UnicodeString to hold the matched descriptor, or nullptr.
* @param status the error code status.
* @return the service instance, or nullptr.
*/
virtual UObject* handleDefault(const ICUServiceKey& key, UnicodeString* actualReturn, UErrorCode& status) const;
/**
* <p>Clear caches maintained by this service.</p>
*
* <p>Subclasses can override if they implement additional caches
* that need to be cleared when the service changes. Subclasses
* should generally not call this method directly, as it must only
* be called while synchronized on the factory lock.</p>
*/
virtual void clearCaches();
/**
* <p>Return true if the listener is accepted.</p>
*
* <p>The default implementation accepts the listener if it is
* a ServiceListener. Subclasses can override this to accept
* different listeners.</p>
*
* @param l the listener to test.
* @return true if the service accepts the listener.
*/
virtual UBool acceptsListener(const EventListener& l) const override;
/**
* <p>Notify the listener of a service change.</p>
*
* <p>The default implementation assumes a ServiceListener.
* If acceptsListener has been overridden to accept different
* listeners, this should be overridden as well.</p>
*
* @param l the listener to notify.
*/
virtual void notifyListener(EventListener& l) const override;
/************************************************************************
* Utilities for subclasses.
*/
/**
* <p>Clear only the service cache.</p>
*
* <p>This can be called by subclasses when a change affects the service
* cache but not the ID caches, e.g., when the default locale changes
* the resolution of IDs also changes, requiring the cache to be
* flushed, but not the visible IDs themselves.</p>
*/
void clearServiceCache();
/**
* <p>Return a map from visible IDs to factories.
* This must only be called when the mutex is held.</p>
*
* @param status the error code status.
* @return a Hashtable containing mappings from visible
* IDs to factories.
*/
const Hashtable* getVisibleIDMap(UErrorCode& status) const;
/**
* <p>Allow subclasses to read the time stamp.</p>
*
* @return the timestamp.
*/
int32_t getTimestamp() const;
/**
* <p>Return the number of registered factories.</p>
*
* @return the number of factories registered at the time of the call.
*/
int32_t countFactories() const;
private:
friend class ::ICUServiceTest; // give tests access to countFactories.
};
U_NAMESPACE_END
/* UCONFIG_NO_SERVICE */
#endif
/* ICUSERV_H */
#endif
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