🚀 go-pugleaf

gary wrote:

> now, i'm wondering if there is a java API equivalent to the Visual C++ 
> "FindFirstChangeNotification() / FindNextChangeNotification()", 

This is not a "Visual C++", or even a "C++" feature - it's a Windows OS 
feature. And no, there's nothing like that in Java.

Java generally doesn't include features that are found only in a single 
OS, and are extremely specific to that OS implementation (like the 
Windows ChangeNotification APIs, etc.).

If you really need to use extremely Windows-specific features, write a 
JNI wrapper, and call that. Your program will then only run on Windows, 
but that's apparently what you want, so that's OK..

shankar:

thanks.  you are right, of course, about the Windows API.  i let myself 
get a bit too terse in my question, which was about performing a task in 
Java that i used to perform in C++ via the mentioned Windows API calls. 
  This got contracted into a mention of non-existent "C++" calls.

i guess your comment about the JNI wrapper is the "right" answer to my 
somewhat screwed up question.  the utility i need is one that would only 
run on windows, because it is meant to support a 3rd-party program that 
only runs under windows.  even so, i'd rather do it in a way that was 
more generic.  in C, i'd probably just traverse directories doing stat() 
calls and looking at timestamps, but i don't know java enough to know 
its file system features yet, so i'll have to look into a rough 
equivalent to this C library call.

thanks for your reply.


Shankar Unni wrote:

> gary wrote:
> 
>> now, i'm wondering if there is a java API equivalent to the Visual C++ 
>> "FindFirstChangeNotification() / FindNextChangeNotification()", 
> 
> 
> This is not a "Visual C++", or even a "C++" feature - it's a Windows OS 
> feature. And no, there's nothing like that in Java.
> 
> Java generally doesn't include features that are found only in a single 
> OS, and are extremely specific to that OS implementation (like the 
> Windows ChangeNotification APIs, etc.).
> 
> If you really need to use extremely Windows-specific features, write a 
> JNI wrapper, and call that. Your program will then only run on Windows, 
> but that's apparently what you want, so that's OK..

On 12/31/2003 at 10:08:49 PM, gary wrote:

> even so, i'd rather do it in a way that was more generic.  in C, i'd
> probably just traverse directories doing stat() calls and looking at
> timestamps, but i don't know java enough to know its file system
> features yet, so i'll have to look into a rough equivalent to this C
> library call.

See the java.io.File class.  You can list the contents of a directory
with the list() or listFiles() methods on a File object that refers to
a directory.  You can get attributes of a file using methods such as
lastModified(), canRead(), canWrite(), and length().

-- 
Regards,

John McGrath [TeamB]

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gary wrote:

> in C, i'd probably just traverse directories doing stat() 
> calls and looking at timestamps, 

Oh, hey, if you're willing to do that, there's a portable way to do it: 
use the java.io.File class.

File has a lot of "stat"-like information, and you can use 
File.listFiles() to list all the Files under a File which corresponds to 
a directory (e.g. new File("c:\\temp").listFiles()).  Just walk the 
array, and look at the lastModified() time. Be prepared to test 
isDirectory() and recursively walk any subdirectories.

This is definitely not efficient, either time or memory wise (the 
listFiles() will do a full ls -d inside the directory and return you one 
giant list, so if you have 100000 files in that directory, watch out). 
But it's quite portable.