#-------------------------------------------------------------------------------
# CLASS DEF
#-------------------------------------------------------------------------------

Shabubu <- setRefClass(
	Class="Shabubu",
	fields=list(
		BUFFER="environment",
		HISTORY="environment",
		DYNCNTRL="environment",
		main="data.frame"
	),
 	methods=list(
		# GENERIC
		GENERATOR=function() getRefClass("Shabubu"), 
		fields=function() GENERATOR()$fields(),
		methods=function() GENERATOR()$methods(),
#		accessors=function() GENERATOR()$accessors,
		# /
		# DATA RETRIEVAL
		data.retrieve=function() data.retrieve.core(.self=.self),
		# /
		# BUFFER
		buffer.refresh=function() assign("main", data.retrieve(), envir=BUFFER),  
		buffer.clean=function() rm(list=ls(BUFFER, all.names=TRUE), envir=BUFFER),
		# /
		# DYNCNTRL
		dyncntrl.set=function(field, arg, val)
		{
			if(!exists(field, DYNCNTRL)) 
				assign(field, new.env(parent=emptyenv()), DYNCNTRL)
			
			assign(arg, val, get(field, DYNCNTRL))
			cat(paste("Setting '", arg, "=", val, "' for field '", field, 
				"'.", sep=""), sep="\n")
		},
		dyncntrl.get=function(field, arg)
		{
			if(!exists(field, DYNCNTRL)) return(NULL)
			if(!exists(arg, get(field, DYNCNTRL))) return(NULL)
			
			get(arg, get(field, DYNCNTRL))
		},
		# /
		# STATIC
		static.clean=function(field)
		{
			expr <- paste("cls <- class(", field, ")", sep="")
			eval(parse(text=expr))
			expr.val <- paste("as.", cls, "(NULL)", sep="")
			expr <- paste(field, " <<- ", expr.val, sep="")
			eval(parse(text=expr))
			cat(paste("Removing values for field '", field, "' (STATIC).", 
				sep=""), sep="\n")
		},
		# /
		# GET
		main.get=function(
			do.static=dyncntrl.get(field="main", arg="do.static"),
			do.buffer.clean=dyncntrl.get(field="main", arg="do.buffer.clean")
		)	
		{
			if(is.null(do.static))
			{
				dyncntrl.set(field="main", arg="do.static", val=TRUE)	
				do.static <- dyncntrl.get(field="main", arg="do.static")
			}
			if(is.null(do.buffer.clean))
			{
				dyncntrl.set(field="main", arg="do.buffer.clean", val=FALSE)	
				do.buffer.clean <- dyncntrl.get(field="main", 
					arg="do.buffer.clean")
			}
			if(do.static)
			{
				cat("Field 'main' (STATIC).", sep="\n")
				if(!length(main))
				{
					cat("Initializing ...", sep="\n")
					main <<- main.get(do.static=FALSE, do.buffer.clean=TRUE)
				}
				rtn <- main
			} else 
			{
				cat("Field 'main' (DYNAMIC).", sep="\n")
				# REFRESH BUFFER
				buffer.refresh()
				# /
				rtn <- BUFFER$main
				if(do.buffer.clean)
				{
					cat("Cleaning BUFFER.", sep="\n")
					buffer.clean()
				}	
			}
			return(rtn)
		},
		# /
		# SET
		main.set=function(
			val,
			do.update.remote=dyncntrl.get(field="main", arg="do.update.remote")
		)	
		{
			if(is.null(do.update.remote))
			{
				dyncntrl.set(field="main", arg="do.update.remote", val=FALSE)
				do.update.remote <- dyncntrl.get(field="main", 
					arg="do.update.remote")
			}
			cat("Setting value for field 'main' (STATIC).", sep="\n")
			main <<- val
			if(do.update.remote)
			{
				cat("Updating remote data linked to field 'main'.", sep="\n")
				BUFFER$main <<- val
				data.writeback.core(.self=.self, val=val)	
			}
		}
		# /
	)
)

# /CLASS DEF -----

#-------------------------------------------------------------------------------
# GENERICS
#-------------------------------------------------------------------------------

setGeneric(name="data.retrieve.core", 
	def=function(.self, ...){standardGeneric("data.retrieve.core")},
	signature=c(".self")
)
setGeneric(name="data.writeback.core", 
	def=function(.self, val, ...){standardGeneric("data.writeback.core")},
	signature=c(".self")
)

# /GENERICS -----

#-------------------------------------------------------------------------------
# METHODS
#-------------------------------------------------------------------------------

setMethod(
	f="data.retrieve.core", 
	signature=signature("Shabubu"), 
	definition=function(.self, ...)
	{
		cat("THIS IS THE METHOD FOR 'SHABUBU'.", sep="\n")
		rtn <- DB$Shabubu
		return(rtn)
	}
)
setMethod(
	f="data.writeback.core", 
	signature=signature("Shabubu"), 
	definition=function(.self, val, ...)
	{
		cat("THIS IS THE METHOD FOR 'SHABUBU'.", sep="\n")
		DB$Shabubu <- val
		return(TRUE)
	}
)

# /METHODS -----

#-------------------------------------------------------------------------------
# EXAMPLE
#-------------------------------------------------------------------------------

# Environment as database imitation (remote location):
DB 			<- new.env(parent=emptyenv())
DB$Shabubu 	<- data.frame(a=1:10, b=letters[1:10])
DB$Shabubu

# Instance init:
shabubu <- Shabubu$new()
shabubu$GENERATOR() 
shabubu$fields()
shabubu$methods()

shabubu$main
# Get dynamical value for 'main' (as default for 'do.static=FALSE'):
shabubu$main.get()	
# In case I'd wanted static values before dynamic values were ever retrieved,
# the method automatically takes care of initialization.
ls(shabubu$BUFFER)	
# BUFFER was cleaned right after dynamic retrieval because default for 
# do.buffer.clean=TRUE

shabubu$main
# Get static value for 'main' via explicitly setting 'do.static':
shabubu$main.get(do.static=TRUE)	

# Get dynamic value for 'main' without cleaning buffer afterwards:
shabubu$main.get(do.static=FALSE, do.buffer.clean=FALSE)	
ls(shabubu$BUFFER)
shabubu$BUFFER$main

# Inspect method defaults:
shabubu$dyncntrl.get(field="main", arg="do.static")
shabubu$dyncntrl.get(field="main", arg="do.buffer.clean")
shabubu$dyncntrl.get(field="main", arg="do.update.clean")

# Change defaults:
shabubu$dyncntrl.set(field="main", arg="do.static", val=TRUE)
shabubu$dyncntrl.set(field="main", arg="do.buffer.clean", val=FALSE)
shabubu$dyncntrl.set(field="main", arg="do.update.clean", val=FALSE)

# As default was changed, this now calls the static value:
shabubu$main.get()	

shabubu$main.set(val=shabubu$main[1:5,])
shabubu$main			# Values changed
shabubu$main.get()
shabubu$main.get(do.static=FALSE)
shabubu$main.set(val=shabubu$main.get(do.static=FALSE))
shabubu$main
shabubu$main.set(val=shabubu$main[1:5,], do.update.remote=TRUE)
DB$Shabubu	# Values in DB changed

# Cleaning fields:
shabubu$static.clean(field="main")
shabubu$main	# Values gone

# /EXAMPLE