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UniRetryGen Class Reference

A UniConfGen that reconnects to an inner generator specified by a moniker whenever the inner generator is no longer OK. More...

#include <uniretrygen.h>

Inheritance diagram for UniRetryGen:
Inheritance graph
[legend]

List of all members.

Public Types

typedef wv::function< void(UniRetryGen &)> ReconnectCallback
typedef ::UniListIter ListIter
 An iterator over a constant list of keys (see below)

Public Member Functions

 UniRetryGen (WvStringParm _moniker, ReconnectCallback _reconect_callback=ReconnectCallback(), time_t _retry_internal_ms=5000)
virtual void commit ()
 Commits any changes.
virtual bool refresh ()
 Refreshes information about a key recursively.
virtual void prefetch (const UniConfKey &key, bool recursive)
 Indicate that we will eventually be interested in doing get(), haschildren(), or other "get-like" operations on a particular key or tree of keys.
virtual void flush_buffers ()
 Flushes any commitment/notification buffers .
virtual WvString get (const UniConfKey &key)
 Fetches a string value for a key from the registry.
virtual void set (const UniConfKey &key, WvStringParm value)
 Stores a string value for a key into the registry.
virtual bool exists (const UniConfKey &key)
 Without fetching its value, returns true if a key exists.
virtual bool haschildren (const UniConfKey &key)
 Returns true if a key has children.
virtual bool isok ()
 Determines if the generator is usable and working properly.
virtual Iteriterator (const UniConfKey &key)
 Returns an iterator over the children of the specified key.
virtual Iterrecursiveiterator (const UniConfKey &key)
 Like iterator(), but the returned iterator is recursive, that is, it will return children of the immediate children, not just the immediate children themselves.
IUniConfGeninner () const
 Returns the inner generator.
virtual bool keymap (const UniConfKey &unmapped_key, UniConfKey &mapped_key)
 A mapping function for filters that remap one keyspace onto another.
virtual bool reversekeymap (const UniConfKey &mapped_key, UniConfKey &unmapped_key)
 A mapping function for filters that unmap a keyspace.
virtual void setv (const UniConfPairList &pairs)
 Stores multiple key-value pairs into the registry.
virtual void add_callback (void *cookie, const UniConfGenCallback &callback)
 Adds a callback for change notification.
virtual void del_callback (void *cookie)
 Removes a callback for change notification.
void dispatch_delta (const UniConfKey &key, WvStringParm value)
 Immediately sends notification that a key has possibly changed.
void hold_delta ()
 Pauses notifications until matched with a call to unhold_delta().
void unhold_delta ()
 Resumes notifications when each hold_delta() has been matched.
void clear_delta ()
 Clears the list of pending notifications without sending them.
void flush_delta ()
 Flushes the list of pending notifications by sending them.
void delta (const UniConfKey &key, WvStringParm value)
 Call this when a key's value or children have possibly changed.
virtual int str2int (WvStringParm s, int defvalue) const
 Converts a string to an integer.
virtual unsigned int addRef ()=0
 Indicate you are using this object.
virtual unsigned int release ()=0
 Indicate that you are finished using this object.
virtual IObjectgetInterface (const UUID &)=0
 Returns the requested XPLC interface.
virtual IWeakRefgetWeakRef ()=0
 Return a weak reference to this object.

Protected Member Functions

void setinner (IUniConfGen *inner)
 Rebinds the inner generator and prepares its callback.
virtual void gencallback (const UniConfKey &key, WvStringParm value)
 Called by inner generator when a key changes.
void setv_naive (const UniConfPairList &pairs)

Detailed Description

A UniConfGen that reconnects to an inner generator specified by a moniker whenever the inner generator is no longer OK.

It will try to periodically recreate the inner generator until the resulting object returns isok() true.

The UniRetryGen's moniker takes either of the forms retry:<inner moniker>=""> or retry:{<inner moniker>=""> <retry timeout>="">}; in the second form the retry timeout is specified in milliseconds. If not specified, the retry timout is 5000ms. Specifically this means that whenever the retry generator is does not have a good inner generator and at least 5000ms have passed since the disconnect or last reconnect attempt, reconnection will be attempted again.

The connection is created through the underlying backend's moniker and destroyed by delete.

If UniRetryGen's constructor is used directly, a callback of type UniRetryGen::ReconnectCallback can be specified, which will be called whenever the UniRetryGen reconnects to the underlying moniker. This allows for any necessary resynchronisation, such as a call to refresh().

UniRetryGen can be used in combination with UniReplicateGen to create a connection to a UniConf daemon that is robust against network failures through a moniker such as replicate:{retry:tcp:192.168.0.1 tmp:}

Definition at line 41 of file uniretrygen.h.


Member Function Documentation

void UniRetryGen::commit ( ) [virtual]

Commits any changes.

The default implementation does nothing.

Reimplemented from UniFilterGen.

Definition at line 124 of file uniretrygen.cc.

References UniFilterGen::isok().

bool UniRetryGen::refresh ( ) [virtual]

Refreshes information about a key recursively.

May discard uncommitted data.

The default implementation always returns true.

Reimplemented from UniFilterGen.

Definition at line 135 of file uniretrygen.cc.

References UniFilterGen::isok().

void UniRetryGen::prefetch ( const UniConfKey key,
bool  recursive 
) [virtual]

Indicate that we will eventually be interested in doing get(), haschildren(), or other "get-like" operations on a particular key or tree of keys.

The generator may be able to speed up these operations by, say, caching them in advance.

This function is not allowed to do blocking operations. It is allowed to do nothing at all, however, and then get() might block later.

Reimplemented from UniFilterGen.

Definition at line 151 of file uniretrygen.cc.

References UniFilterGen::isok().

virtual void UniRetryGen::flush_buffers ( ) [inline, virtual]

Flushes any commitment/notification buffers .

The default implementation always returns true. NOTE: This method should be 'protected'

Reimplemented from UniFilterGen.

Definition at line 72 of file uniretrygen.h.

WvString UniRetryGen::get ( const UniConfKey key) [virtual]

Fetches a string value for a key from the registry.

If the key doesn't exist, the return value has .isnull() == true.

Reimplemented from UniFilterGen.

Definition at line 162 of file uniretrygen.cc.

References WvFastString::cstr(), UniFilterGen::isok(), and UniConfKey::printable().

void UniRetryGen::set ( const UniConfKey key,
WvStringParm  value 
) [virtual]

Stores a string value for a key into the registry.

If the value is WvString::null, the key is deleted.

Reimplemented from UniFilterGen.

Definition at line 189 of file uniretrygen.cc.

References UniFilterGen::isok().

bool UniRetryGen::exists ( const UniConfKey key) [virtual]

Without fetching its value, returns true if a key exists.

This is provided because it is often more efficient to test existance than to actually retrieve the value.

The default implementation returns !get(key).isnull().

Reimplemented from UniFilterGen.

Definition at line 200 of file uniretrygen.cc.

References WvFastString::cstr(), UniFilterGen::isok(), and UniConfKey::printable().

bool UniRetryGen::haschildren ( const UniConfKey key) [virtual]

Returns true if a key has children.

This is provided because it is often more efficient to test existance than to actually retrieve the keys.

The default implementation uses the iterator returned by iterator() to test whether the child has any keys. Subclasses are strongly encouraged to provide a better implementation.

Reimplemented from UniFilterGen.

Definition at line 234 of file uniretrygen.cc.

References UniFilterGen::isok().

bool UniRetryGen::isok ( ) [virtual]

Determines if the generator is usable and working properly.

The default implementation always returns true.

Reimplemented from UniFilterGen.

Definition at line 250 of file uniretrygen.cc.

UniConfGen::Iter * UniRetryGen::iterator ( const UniConfKey key) [virtual]

Returns an iterator over the children of the specified key.

May return NULL or an empty iterator if the key has no children.

The caller takes ownership of the returned iterator and is responsible for deleting it when finished.

Reimplemented from UniFilterGen.

Definition at line 262 of file uniretrygen.cc.

References UniFilterGen::isok().

Like iterator(), but the returned iterator is recursive, that is, it will return children of the immediate children, not just the immediate children themselves.

May return NULL if the key has no immediate children (since that means there are also no indirect children).

Note that UniConfGen::recursiveiterator() is a default implementation that just calls iterator() recursively, so it'll work in any derived class without you overriding this function. However, you might want to do it anyway if it would be more efficient in your particular case.

Reimplemented from UniFilterGen.

Definition at line 278 of file uniretrygen.cc.

void UniFilterGen::setinner ( IUniConfGen inner) [protected, inherited]

Rebinds the inner generator and prepares its callback.

The previous generator is NOT destroyed.

Definition at line 26 of file unifiltergen.cc.

References IUniConfGen::add_callback(), IUniConfGen::del_callback(), UniFilterGen::gencallback(), and UniFilterGen::inner().

IUniConfGen* UniFilterGen::inner ( ) const [inline, inherited]

Returns the inner generator.

Definition at line 33 of file unifiltergen.h.

Referenced by UniDefGen::get(), UniDefGen::set(), UniPermGen::setgroup(), UniFilterGen::setinner(), and UniPermGen::setowner().

bool UniFilterGen::keymap ( const UniConfKey unmapped_key,
UniConfKey mapped_key 
) [virtual, inherited]

A mapping function for filters that remap one keyspace onto another.

The default implementation of the various functions (get, set, exists, etc) run their keys through this function before forwarding the requests on to the inner generator.

The default implementation of this function doesn't change the key.

Returns true if the key can be mapped, else false.

Reimplemented in UniDefGen, UniAutoMountGen, and UniSubtreeGen.

Definition at line 37 of file unifiltergen.cc.

Referenced by UniFilterGen::exists(), UniFilterGen::get(), UniFilterGen::haschildren(), UniFilterGen::iterator(), UniFilterGen::prefetch(), UniFilterGen::recursiveiterator(), and UniFilterGen::set().

bool UniFilterGen::reversekeymap ( const UniConfKey mapped_key,
UniConfKey unmapped_key 
) [virtual, inherited]

A mapping function for filters that unmap a keyspace.

The default implementation of this function doesn't change the key.

Returns true if the key can be reverse-mapped, else false.

Reimplemented in UniSubtreeGen.

Definition at line 44 of file unifiltergen.cc.

Referenced by UniFilterGen::gencallback().

void UniFilterGen::setv ( const UniConfPairList &  pairs) [virtual, inherited]

Stores multiple key-value pairs into the registry.

If the value is WvString::null, the key is deleted.

Implements UniConfGen.

Definition at line 101 of file unifiltergen.cc.

References IUniConfGen::setv().

void UniFilterGen::gencallback ( const UniConfKey key,
WvStringParm  value 
) [protected, virtual, inherited]

Called by inner generator when a key changes.

The default implementation calls delta(key).

Reimplemented in UniFastRegetGen.

Definition at line 157 of file unifiltergen.cc.

References UniConfGen::delta(), and UniFilterGen::reversekeymap().

Referenced by UniFilterGen::setinner().

void UniConfGen::add_callback ( void *  cookie,
const UniConfGenCallback &  callback 
) [virtual, inherited]

Adds a callback for change notification.

Must *not* be reimplemented by subclasses of UniConfGen.

Implements IUniConfGen.

Definition at line 158 of file uniconfgen.cc.

Referenced by UniConfRoot::UniConfRoot().

void UniConfGen::del_callback ( void *  cookie) [virtual, inherited]

Removes a callback for change notification.

Implements IUniConfGen.

Definition at line 165 of file uniconfgen.cc.

Referenced by UniConfRoot::~UniConfRoot().

void UniConfGen::dispatch_delta ( const UniConfKey key,
WvStringParm  value 
) [inherited]

Immediately sends notification that a key has possibly changed.

Takes care of the details of invoking the callback.

Note: You probably want to be using delta() instead.

Definition at line 71 of file uniconfgen.cc.

Referenced by UniConfGen::delta(), and UniConfGen::flush_delta().

void UniConfGen::hold_delta ( ) [inherited]

Pauses notifications until matched with a call to unhold_delta().

While paused, notification events are placed into a pending list. Redundant notifications may be discarded.

Use this to safeguard non-reentrant code.

Definition at line 32 of file uniconfgen.cc.

Referenced by UniTransactionGen::commit(), UniMountGen::commit(), UniConfGen::delta(), UniConfGen::haschildren(), UniMountGen::mountgen(), UniIniGen::refresh(), UniTransactionGen::refresh(), UniMountGen::refresh(), UniTempGen::set(), UniClientGen::set(), UniTransactionGen::set(), UniClientGen::setv(), UniTransactionGen::setv(), and UniMountGen::unmount().

void UniConfGen::unhold_delta ( ) [inherited]

Resumes notifications when each hold_delta() has been matched.

On resumption, dispatches all pending notifications except those that were destined to watches that were removed.

Use this to safeguard non-reentrant code.

Definition at line 38 of file uniconfgen.cc.

References UniConfGen::flush_delta().

Referenced by UniTransactionGen::commit(), UniMountGen::commit(), UniConfGen::delta(), UniConfGen::haschildren(), UniMountGen::mountgen(), UniIniGen::refresh(), UniTransactionGen::refresh(), UniMountGen::refresh(), UniTempGen::set(), UniClientGen::set(), UniTransactionGen::set(), UniClientGen::setv(), UniTransactionGen::setv(), and UniMountGen::unmount().

void UniConfGen::clear_delta ( ) [inherited]

Clears the list of pending notifications without sending them.

Does not affect the hold nesting count.

Definition at line 47 of file uniconfgen.cc.

void UniConfGen::flush_delta ( ) [inherited]

Flushes the list of pending notifications by sending them.

Does not affect the hold nesting count.

Definition at line 53 of file uniconfgen.cc.

References UniConfGen::dispatch_delta().

Referenced by UniConfGen::unhold_delta().

void UniConfGen::delta ( const UniConfKey key,
WvStringParm  value 
) [inherited]
int UniConfGen::str2int ( WvStringParm  s,
int  defvalue 
) const [virtual, inherited]

Converts a string to an integer.

If the string is null or not recognized, return defvalue.

This is here to support the common str2int(get(key)).

The default implementation recognizes the booleans 'true', 'yes', 'on' and 'enabled' as 1, and 'false', 'no', 'off' and 'disabled' as 0.

Implements IUniConfGen.

Definition at line 126 of file uniconfgen.cc.

References WvFastString::cstr(), and WvFastString::isnull().

virtual unsigned int IObject::addRef ( ) [pure virtual, inherited]

Indicate you are using this object.

This increases the reference count of the object by one. Usually, when the reference count reaches zero, the object is freed automatically.

This called a "strong reference", because they will prevent the object from being destroyed. They should thus be used carefully, as they control the lifetime of the object. For example, you do not need to call addRef() on object passed as parameters, unless you intend on keeping them.

addRef() is often called automatically for you in XPLC, but you'll have to call release() by hand sometimes unless you use xplc_ptr.

Referenced by WvIStreamList::execute(), IObjectImplInternal::getInterface(), StaticServiceHandler::getObject(), WeakRef::getObject(), WvIStreamList::post_select(), WvQtStreamClone::WvQtStreamClone(), and WvSSLStream::WvSSLStream().

virtual unsigned int IObject::release ( ) [pure virtual, inherited]

Indicate that you are finished using this object.

This decreases the reference count of the object by one. Usually, when the reference count reaches zero, the object is freed automatically.

You will usually need to manually release() any object given to you by any other XPLC function, unless you give the object to someone else who will call release.

If you use xplc_ptr, it will do this for you.

Referenced by WvIStreamList::execute(), mutate(), NewMoniker::resolve(), and MonikerService::resolve().

virtual IObject* IObject::getInterface ( const UUID ) [pure virtual, inherited]

Returns the requested XPLC interface.

Will return NULL if the interface is not supported. The returned interface has been addRef()ed, so you will need to release() it when done. Note that the interface returned may be a pointer to the same object or a different one - that's none of your business. Asking for the IObject interface should always return the same pointer for a given logical object, so this can be used for comparison by identity.

You should probably use the convenient mutate() and get() functions instead of this, or use an xplc_ptr, which mutates the object for you.

Referenced by mutate().

virtual IWeakRef* IObject::getWeakRef ( ) [pure virtual, inherited]

Return a weak reference to this object.

A weak reference points at the object, but does not control the lifetime of the object. An object can thus still be deleted while someone holds a weak reference. You will still need to release() the weak reference when you are done with it.

See also:
IWeakRef

The documentation for this class was generated from the following files: