[X10-core] Java Interop Puzzle

[Bard B. <ba...@us...>]

Here's a little X10 puzzle.

I've got a *Java* method I need to call from X10:
  table.get(get);
This method can throw java.io.IOException, so I have to wrap calls to it in
a
try/catch block.   If I don't, I get Java compilation errors:

    x10c: ----------
         1. ERROR in clsss/xjj/HTabler.java (at line 474)
         	thingTable.get(((org.apache.hadoop.hbase.client.Get)(this.
         get)));

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

         Unhandled exception type IOException
         ----------
         1 problem (1 error)
    x10c: Non-zero return code: 255

So I have to put a try/catch around it:
        try {
          return thingTable.get(get);
        }
        catch(e:x10.lang.Exception) {
          e.printStackTrace();
          throw new RuntimeException("Oh no from
HTabler.retrieveThingRecord!  " + e);
        }

And that compiles fine.  (I'm a bit confused about why, since I didn't
think
java.io.IOException was consistent with x10.lang.Exception.)

But what I really want to do is write a method that behaves like various
things named 'with' in LISP and Python and such.
  public static def withThingTable[T]( body : (HTableInterface) => T ) {T
haszero} : T
So that withThingTable(useThingTable) will call the function useThingTable
on
a properly-opened Thing Table, and, after it's done (even exceptionally)
will
properly close it.

withThingTable is pretty careful with catching exceptions, so it should run
OK.   It's a convenience method, encapsulating a required programming
pattern.

The point of a convenience method is that it be convenient. I *want* to
write:
   return withThingTable( (tt:HTableInterface) => tt.get(get) )

But X10 and Java don't know that I'm being careful with exceptions.  So I
have
to write the try/catch block inside the closure:

      return withThingTable[Result]((thingTable:HTableInterface) => {
        try {
          return thingTable.get(get);
        }
        catch(e:x10.lang.Exception) {
          e.printStackTrace();
          throw new RuntimeException("Oh no from
HTabler.retrieveThingRecord!  " + e);
        }
        });

And this makes my convenience method not so convenient.

Any suggestions about how I could avoid having to write the try/catch block
in
the closure?  Preferably without having to write my own 'get' (and all N
other
HBase methods)?

Thanks,

 Bard