I have a Java application that will be used both from the Windows Command Prompt and the Cygwin terminal. The program uses and manipulates file paths. It we be very useful to have a sep variable that would be / when the program is launched from Cygwin but \\ when the program is launched from Windows.
Looking here, I'm not sure it will be possible, but I want to ask.
I will post a small, compilable app that shows the issue in a few minutes. For now, I'll just say that I want a set of functions that something like:
// in main
...
String sep = getSeparatorToUse();
...
// member functions
...
private boolean wasLaunchedFromWinCmd()
{
if (<something-here-that-knows-it-was-cmd-not-cygwin>)
return true;
return false;
}//endof: private boolean wasLaunchedFromWinCmd()
private String getSeparatorToUse()
{
if (wasLaunchedFromWinCmd)
return "\\"
return "/"
}//endof: private String getSeparatorToUse()
Thanks @Raphael_Moita. Those are very useful, and I will likely use them in the Linux version of the app that I will be using. @Luke_Lee, I feel dumb not having realized it. I think you two might have solved my problem while I was getting the compilable code ready. There's still one issue when the program run from a batch script - when it is fed a filename from a find command. I hope what I show will illustrate that.
Examples
All examples are as run from Cygwin.
Works: the way most volunteers use the code, just the filename that's in the same directory as the java code.
$ java FileSeparatorExample pic_4.jpg
Here, something will be done with the file,
C:\Users\bballdave025\Desktop\pic_4.jpg
Works: with relative filepaths and spaces in filenames/file paths
$ java FileSeparatorExample pretty\ pictures/pic\ 1.jpg
Here, something will be done with the file,
C:\Users\me\Desktop\pretty pictures/pic 1.jpg
$ java FileSeparatorExample ../pic_5.jpg
Here, something will be done with the file,
C:\Users\me\Desktop\../pic_5.jpg
DOESN'T WORK. Sometimes, the output of a find command will come with the complete filepath in Cygwin/UNIX format:
$ java FileSeparatorExample /cygdrive/c/David/example/pic.jpg
The file:
C:\Users\bballdave025\Desktop\/cygdrive/c/David/example/pic.jpg
doesn't exist
Compilable Code
I'm just cutting down from my original code, so I'm sorry if it seems too big.
/**********************************
* @file FileSeparatorExample.java
**********************************/
// Import statements
import java.io.File;
import java.io.IOException;
public class FileSeparatorExample
{
// Member variables
private static String sep;
public static void main(String[] args)
{
////****** DOESN'T WORK AS DESIRED ******////
sep = java.io.File.separator;
////** I want **////
// sep = getFileSeparator();
String imageToLoad = null;
boolean argumentExists = ( args != null && args.length != 0 );
if (argumentExists)
{
boolean thereIsExactlyOneArgument = ( args.length == 1 );
if (thereIsExactlyOneArgument)
{
imageToLoad = args[0];
}//endof: if (thereIsExactlyOneArgument)
else
{
// do some other stuff
}
}//endof: if (argumentExists)
String filenamePath = getFilenamePath(imageToLoad);
String filenameFile = getFilenameFile(imageToLoad);
imageToLoad = filenamePath + sep + filenameFile;
File f = new File(imageToLoad);
if (! f.exists())
{
System.err.println("The file:");
System.err.println(imageToLoad);
System.err.println("doesn\'t exist");
System.exit(1);
}//endof: if (! f.exists())
System.out.println("Here, something will be done with the file,");
System.out.println(imageToLoad);
}//endof: main
// member methods
/**
* Separates the filename arg into: full path to directory; bare filename
*/
private static String[] splitFilename(String imageToLoad)
{
String[] fileParts = new String[2];
int indexOfLastSep = imageToLoad.lastIndexOf(sep);
boolean fullFilenameHasSeparator = ( indexOfLastSep != -1 );
if (fullFilenameHasSeparator)
{
fileParts[0] = imageToLoad.substring(0, indexOfLastSep);
fileParts[1] = imageToLoad.substring(indexOfLastSep + 1);
}//endof: if (fullFilenameHasSeparator)
else
{
// Use the user's directory as the path
fileParts[0] = System.getProperty("user.dir");
fileParts[1] = imageToLoad;
}//endof: if/else (fullFilenameHasSeparator)
return fileParts;
}//endof: private static String[] splitFilename(String imageToLoad)
/**
* Gives the full path to the file's directory (from the filename arg)
* but not the bare filename
*/
private static String getFilenamePath(String imageToLoad)
{
String[] fileParts = splitFilename(imageToLoad);
return fileParts[0];
}//endof: private static String getFilenamePath(String imageToLoad)
/**
* Gives the bare filename (no path information)
*/
private static String getFilenameFile(String imageToLoad)
{
String[] fileParts = splitFilename(imageToLoad);
return fileParts[1];
}//endof: private static String getFilenamePath(String imageToLoad)
}//endof: public class FileSeparatorExample
You don't need to know which SO is under your Java. If your goal is to find the correct file separator to use, call this:
java.io.File.separator;
Anyway ... to find out which SO java is running over (not sure how cygwin is detected by this), try:
boolean isWindows = System.getProperty("os.name").startsWith("win");