R/xlcCall.R

In XLConnect: Excel Connector for R

#############################################################################
#
# XLConnect
# Copyright (C) 2010-2024 Mirai Solutions GmbH
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#
#############################################################################

#############################################################################
#
# Utility function for vectorizing argument lists and default Java exception
# handling (jTryCatch)
#
# Atomic objects are replicated as is, others are wrapped in a list as defined
# by wrapList and then replicated
# 
# Author: Martin Studer, Mirai Solutions GmbH
#
#############################################################################

xlcCall <- function(obj, fun, ..., .recycle = TRUE, .simplify = TRUE,
					.checkWarnings = TRUE, .withAttributes = FALSE) {
	
	g = eval(parse(text = paste("obj@jobj$", fun, sep = "")))
	f <- if (.withAttributes) function(...) withAttributesFromJava(g(...)) else g
	args <- list(...)
	
	if (.recycle) {
		args <- lapply(args, function(x) {
			if (is.atomic(x)) x
			else wrapList(x)
		})
		
		res = jTryCatch(do.call("mapply", args = c(FUN = f, args, SIMPLIFY = FALSE)))
		
		if (.simplify) {
			if (.withAttributes) {
				attrs_of_results <- lapply(res, attributes)
				res_attr <- 
					Reduce(
						function(atts1, atts2) { # TODO is Reduce idiomatic ? 
							aNames <- unique(c(names(atts1), names(atts2)))
							sapply(aNames, function(aName) { list(c(atts1[aName][[1]], atts2[aName][[1]])) })
						},
						attrs_of_results
					)
				res <- simplify2array(res)
				attributes(res) <- res_attr
			} else {
				res <- simplify2array(res)
			}
		}
	} else {
		res = jTryCatch(do.call(f, args))
	}

	if (.checkWarnings) {
		warnings = .jcall(obj@jobj, "[S", "retrieveWarnings")
		for(w in warnings) warning(w, call. = FALSE)
	}
	
	res
}