Connection::VariablesCache Class Reference

The class to handle variable caches. More...

#include <connection.h>

Public Member Functions
	VariablesCache (Connection *connection)
	The constructor.
	~VariablesCache ()
	The destructor.
Globals::Results	update (VariablesDict &varDict, bool useCoherentValues)
	Updates the variables' cache with the current dictionary values.
Globals::Results	getCacheItem (Client &client, uint32_t cacheId, bool forceVarDictUpdate, bool useCoherentValues, bool checkFullVar, uint32_t startMsgOffset, uint32_t splitOffset, VariablesCacheItem *&vcache)
	Query a cached item given its ID.
uint32_t	add (const String &name, const String &extraTag="")
	Adds a variable to the cache.
bool	contains (uint32_t cacheId)
	Helper to check if cacheId is a valid identifier stored into the cache.
uint32_t	find (const String &name, const String &extraTag="")
	Check if the variable of specified in name with extraTag is cached.
Globals::Results	remove (uint32_t cacheId)
	Removes the variable specified by cacheId from the cache.
Message::DataTypes	dataType (uint32_t cacheId)
	Get the data types for the specified cacheId stored into the cache.
uint32_t	count ()
	Get the number of cached items.
void	clear ()
	Clears the variables' cache removing all the cached variables.
void	cleanup ()
	Clears each cached variable without removing the cache entry.
VariablesCacheItem *	item (uint32_t cacheId)
	Returns the pointer to the cache item with cache id cacheId
bool	needUpdate () const
	get the flag to indicate if the variable cache needs to be udpated

Protected Types
typedef std::map< uint32_t, VariablesCacheItem * >	VariablesCacheItemHash

Protected Member Functions
uint32_t	getCacheId (const String &name, const String &extraTag)
	Get the cache identifier from the name.
VariablesCacheItemHash &	varCaches ()
	Get the cached variable dictionary ( See also VariablesCacheItem )
Connection *	connection () const
	Get the connection internal object.
void	setNeedUpdate (bool value)
	Set/reset the flag for variable cache to be udpated on the next operation using the cache.

Detailed Description

The class to handle variable caches.

Member Typedef Documentation

VariablesCacheItemHash

typedef std::map<uint32_t, VariablesCacheItem*> VariablesCacheItemHash

protected

Constructor & Destructor Documentation

VariablesCache()

VariablesCache

(

Connection *

connection

)

The constructor.

Parameters

connection

The connection to use

~VariablesCache()

~VariablesCache

(

)

The destructor.

Member Function Documentation

add()

uint32_t add	(	const String &	name,
		const String &	extraTag = "" )

Adds a variable to the cache.

Parameters

name	The name of the variable to add to the cache
extraTag	The optional extra tag used in cache id calculation: you can set this to different values to force caching of distinct entries of the same variable

Returns

Returns the variable cache identifier or 0 if some error occurred

All successive operation onto the variable (Client.readVariable(ClientStruct::ReadVariableData &) , Client.writeVariable(ClientStruct::WriteVariableData &) etc) must refer to returned cache identifier

Variable naming convention must the same as RDE.

Using different extraTag values for the same name may be useful to maximize performance when accessing the same variable from Monitor, Client ( e.g. Client.readVariable(ClientStruct::ReadVariableData &), Client.writeVariable(ClientStruct::WriteVariableData &) , Monitor::read(MonitorStruct::ReadData &), etc) or Oscilloscope: in that cases, using different extraTag values (e.g. "MON", "CLIENT", "OSC" ) will force the caching of distinct entry , improving the overall performance

cleanup()

void cleanup

(

)

Clears each cached variable without removing the cache entry.

clear()

void clear

(

)

Clears the variables' cache removing all the cached variables.

connection()

Connection * connection ( ) const

protected

Get the connection internal object.

Returns

The parameter value

contains()

bool contains

(

uint32_t

cacheId

)

Helper to check if cacheId is a valid identifier stored into the cache.

Parameters

cacheId

The cache identifier to check

Returns

Returns true if the cacheId is a valid identifier stored into the cache

count()

uint32_t count

(

)

Get the number of cached items.

Returns

Returns the number of cached items

dataType()

Message::DataTypes dataType

(

uint32_t

cacheId

)

Get the data types for the specified cacheId stored into the cache.

Parameters

cacheId

The cache identifier for which to get the data type

Returns

Returns the Message::DataTypes for the cached variable if the cacheId was found , or Message::DataTypes::dtUndef if not found

find()

uint32_t find	(	const String &	name,
		const String &	extraTag = "" )

Check if the variable of specified in name with extraTag is cached.

Parameters

name	The name of the variable to earch for
extraTag	The optional extra tag used in cache id calculation See also addToVarsCache(const String &, const String &)

Returns

Returns the variable cache identifier or 0 if some error occurred or variable not cached

The search is case insensitive: leading and traling whites char are trimmed.

getCacheId()

uint32_t getCacheId ( const String & name, const String & extraTag )

protected

Get the cache identifier from the name.

The id is calculated from the 'normalized' name i.e the name is trimmed and converted to upper case

Parameters

name	the name from which to get the cache id
extraTag	The extra tag used in cache id calculation: you can set this to different values to force caching of distinct entries of the same variable

Returns

The cache id

getCacheItem()

Globals::Results getCacheItem	(	Client &	client,
		uint32_t	cacheId,
		bool	forceVarDictUpdate,
		bool	useCoherentValues,
		bool	checkFullVar,
		uint32_t	startMsgOffset,
		uint32_t	splitOffset,
		VariablesCacheItem *&	vcache )

Query a cached item given its ID.

Parameters

client	The client to use for comunicate to the device.
cacheId	The identifier of the variable into the cache
forceVarDictUpdate	Flag to force the variable dictionary update
useCoherentValues	Flag to indicate that coherent operations are required, so no packet splitting will be performed
checkFullVar	Flag to enable the variable full check when parsing
startMsgOffset	Message offset to be used on new var
splitOffset	Offset to be applyed to the to the parsing variable logic to properly split the variable. Thats applies when a variable has to be fitted into a BCC message which contains other data (tipcally when using monitors)
vcache	The cache object , or null if some error occurred

Returns

Return the operation result code.

item()

VariablesCacheItem * item

(

uint32_t

cacheId

)

Returns the pointer to the cache item with cache id cacheId

Parameters

cacheId

the item cache id

Returns

Returns the pointer to the item, NULL if no item was found for cacheId

needUpdate()

bool needUpdate

(

)

const

get the flag to indicate if the variable cache needs to be udpated

Returns

The parameter value

remove()

Globals::Results remove

(

uint32_t

cacheId

)

Removes the variable specified by cacheId from the cache.

Parameters

cacheId

The cache identifier to remove

Returns

Returns Globals::resSuccess if the cacheId was found and succesfully removed from cache

setNeedUpdate()

void setNeedUpdate ( bool value )

protected

Set/reset the flag for variable cache to be udpated on the next operation using the cache.

Parameters

value

The value to set

update()

Globals::Results update	(	VariablesDict &	varDict,
		bool	useCoherentValues )

Updates the variables' cache with the current dictionary values.

Parameters

varDict	the variable dictionay to use
useCoherentValues	Flag to ensure coherent values operation

Returns

Return true if each cached variable was successfully updated

varCaches()

QHash< uint32_t, VariablesCacheItem * > & varCaches ( )

protected

Get the cached variable dictionary (

See also

VariablesCacheItem

)

Returns

The parameter value