R/javaVersion.R

In ssaxe-usgs/rgt:

javaVersion <- function(verbose = T, asNum = F){
  # check system type
  sysType <- .Platform$OS.type

  # If windows:
  if ( sysType == 'windows' ){
    ret <- system( command                = "java -version",
                   intern                 = T,
                   show.output.on.console = F )
    # java version
    jv = ret[ grep( pattern     = "java version",
                    x           = ret,
                    ignore.case = T) ]
    jv.matches <- regmatches( x = jv,
                              m = gregexpr( pattern = "[[:digit:]]+",
                                            text    = jv ) )
    jv.version <- as.numeric( x = unlist( x = jv.matches ) )
    jv.version <- paste( jv.version[1], jv.version[2], sep = '.' )

    # Write to console
    if ( verbose ) cat( paste0( "Java version:\n", jv.version, '\n' ) )

    # return
    if ( asNum ){
      return( as.numeric( jv.version ) )
    }else{
      return( jv.version )
    }
  }else{
    stop( "Not currently set up for UNIX systems." )
  }
}