Coprocessor for creating secondary index in Hbase

secondary_index.java

public class TestCoprocessor extends BaseRegionObserver{

    private HTablePool pool = null;

    private final static String  INDEX_TABLE  = "INDEX_TBL";
    private final static String  SOURCE_TABLE = "SOURCE_TBL";

    @Override
    public void start(CoprocessorEnvironment env) throws IOException {  
        pool = new HTablePool(env.getConfiguration(), 10);
    }

    @Override
    public void postPut(
        final ObserverContext<RegionCoprocessorEnvironment> observerContext,
        final Put put,
        final WALEdit edit,
        final boolean writeToWAL)
        throws IOException {

        byte[] table = observerContext.getEnvironment(
            ).getRegion().getRegionInfo().getTableName();

        // Not necessary though if you register the coprocessor
        // for the specific table, SOURCE_TBL
        if (!Bytes.equals(table, Bytes.toBytes(SOURCE_TABLE))) {
            return; 
        }

        try {
            final List<KeyValue> filteredList = put.get(
                Bytes.toBytes ( "colfam1"), Bytes.toBytes(" qaul"));
            filteredList.get( 0 ); //get the column value

            // get the values 
            HTableInterface table = pool.getTable(Bytes.toBytes(INDEX_TABLE));

            // create row key             
            byte [] rowkey = mkRowKey () //make the row key
            Put indexput = new Put(rowkey); 
            indexput.add(
                Bytes.toBytes( "colfam1"),
                Bytes.toBytes(" qaul"),
                Bytes.toBytes(" value.."));

            table.put(indexput);
            table.close();

        } catch ( IllegalArgumentException ex) {
            // handle excepion.
        }

    }


    @Override
    public void stop(CoprocessorEnvironment env) throws IOException {
        pool.close();
    }

}