Hama学习笔记（6）-获取各个peer(task)的信息、确定master task
有时候在bsp job中需要确定一个master task，这就需要获取各个peer(task)的信息，如host name、端口号等等。
hama中获取peer的主机名和端口号很方便：
@SuppressWarnings("unchecked") private final static <KEYIN, VALUEIN, KEYOUT, VALUEOUT, M extends Writable> void runBSP( final BSPJob job, BSPPeerImpl<KEYIN, VALUEIN, KEYOUT, VALUEOUT, M> bspPeer, final BytesWritable rawSplit, final BSPPeerProtocol umbilical) throws Exception { BSP<KEYIN, VALUEIN, KEYOUT, VALUEOUT, M> bsp = (BSP<KEYIN, VALUEIN, KEYOUT, VALUEOUT, M>) ReflectionUtils .newInstance(job.getConfiguration().getClass("bsp.work.class", BSP.class), job.getConfiguration()); // The policy is to throw the first exception and log the remaining. Exception firstException = null; try { bsp.setup(bspPeer); bsp.bsp(bspPeer); } catch (Exception e) { LOG.error("Error running bsp setup and bsp function.", e); firstException = e; } finally { try { bsp.cleanup(bspPeer); } catch (Exception e) { LOG.error("Error cleaning up after bsp executed.", e); if (firstException == null) firstException = e; } finally { try { bspPeer.close(); } catch (Exception e) { LOG.error("Error closing BSP Peer.", e); if (firstException == null) firstException = e; } if (firstException != null) throw firstException; } } }