public void reduce(GFKey key, Iterable<PEIWritable> values, Context context)
        throws IOException, InterruptedException {
      // For a particular key ... process all records and output what we would have expected in this
      // concKnownKeys test
      // Note that we either
      // 1. do a single create
      // 2. create + update
      // 3. create + destroy
      // look at all ops ... and output either
      // 1. create
      // 2. create (with value from update)
      // 3. do nothing (overall result is destroy, so do not create the entry in the gemfire
      // validation region
      String keyStr = (String) key.getKey();
      ValueHolder updateValue = null;
      ValueHolder createValue = null;
      boolean destroyed = false;
      System.out.println("KnownKeysMRv2.reduce() invoked with " + keyStr);
      for (PEIWritable value : values) {
        PersistedEventImpl event = value.getEvent();
        Operation op = event.getOperation();

        ValueHolder vh = null;
        if (op.isDestroy()) {
          destroyed = true;
        } else {
          try {
            vh = (ValueHolder) event.getDeserializedValue();
          } catch (ClassNotFoundException e) {
            System.out.println(
                "KnownKeysMRv2.map() caught " + e + " : " + TestHelper.getStackTrace(e));
          }
          if (op.isUpdate()) {
            updateValue = vh;
          } else {
            createValue = vh;
          }
        }
        System.out.println(
            "KnownKeysMRv2.reduce() record: "
                + op.toString()
                + ": key = "
                + keyStr
                + " and op "
                + op.toString());
      }
      if (!destroyed) {
        if (updateValue != null) {
          context.write(key.getKey(), updateValue);
        } else {
          context.write(key.getKey(), createValue);
        }
      }
    }
    // Identity mapper (log and write out processed key/value pairs, the value is the
    // PersistedEventImpl)
    public void map(GFKey key, PersistedEventImpl value, Context context)
        throws IOException, InterruptedException {

      String keyStr = (String) key.getKey();
      Operation op = value.getOperation();
      ValueHolder entryValue = null;
      System.out.println("map method invoked with " + keyStr + " " + op.toString());
      try {
        entryValue = (ValueHolder) value.getDeserializedValue();
      } catch (ClassNotFoundException e) {
        System.out.println("KnownKeysMRv2.map() caught " + e + " : " + TestHelper.getStackTrace(e));
      }
      context.write(key, new PEIWritable(value));
    }