nws (version 1.6.2)

nwsFetchTry: netWorkSpace Class Method

Description

Attempt to fetch value associates with a variable from the shared netWorkSpace; a non-blocking version of nwsFetch.

Usage

## S3 method for class 'netWorkSpace':
nwsFetchTry(.Object, xName, defaultVal=NULL)

Arguments

.Object

a netWorkSpace class object

xName

name of the variable to be fetched

defaultVal

value to return, if xName is not found in the netWorkSpace

Details

Look in the shared netWorkSpace for a value bound to xName. If found, remove a value associated with xName from the shared netWorkSpace. This operation is atomic. If there are multiple NetWorkSpaces clients nwsFetch or nwsFetchTry a given xName, any given value from the set of values associated with xName will be returned to just one client session.

If variable is not found, return immediately rather than block on the operation (as in the case of nwsFetch). If variable is not found, the value of argument defaultVal is returned. By default, defaultVal is NULL.

See Also

nwsDeclare, nwsFetch

Examples

ws <- netWorkSpace('nws example')
# If variable 'x' is not found in the shared netWorkSpace,
# return default value, NULL.
nwsFetchTry(ws, 'x')
# If variable 'x' is not found in the shared netWorkSpace, return 10.
nwsFetchTry(ws, 'x', 10)