A Java incubator project 'Java Native Access' looks promising :
https://jna.dev.java.net/
Can we include LGPL jar in Hadoop?
From examples, code for accessing atol() from libc looks very simple :
https://jna.dev.java.net/source/browse/jna/trunk/jnalib/src/com/sun/jna/examples/CLibrary.java?rev=7&view=markup
Raghu.
Raghu Angadi wrote:
> I think you'd need to exec a shell command and parse the output.
We might need to invoke this for a lot of blocks at run time.
The use case is that datanode needs to know if a block is also linked by
a back up (after start-dfs.sh -upgrade).
The current use case is when we want to update block metadata when
datanode verifies a block (HADOOP-2012). Shell command might fine for
this. Later this might be used for appends.
Raghu.
Doug Cutting wrote:
Raghu Angadi wrote:
Is there a way to find hard link count for a file in Java? (id
'st_nlink' in struct stat).
I think you'd need to exec a shell command and parse the output.
You could add this to FileUtil.java...
Doug
