@Override
  public void setStoreLocation(String location, Job job) throws IOException {
    Properties udfProps = UDFContext.getUDFContext().getUDFProperties(
        this.getClass(), new String[] { sign });
    udfProps.setProperty(HCatConstants.HCAT_PIG_STORER_EXTERNAL_LOCATION, externalDir);
    super.setStoreLocation(location, job);
  }
This class is used to test the HCAT_PIG_STORER_EXTERNAL_LOCATION property used in HCatStorer.
When this property is set, HCatStorer writes the output to the location it specifies. Since
the property can only be set in the UDFContext, we need this simpler wrapper to do three things:
<ol>
<li> save the external dir specified in the Pig script </li>
<li> set the same UDFContext signature as HCatStorer </li>
<li> before {@link HCatStorer#setStoreLocation(String, Job)}, set the external dir in the UDFContext.</li>
</ol>
hcatalog/hcatalog-pig-adapter/src/test/java/org/apache/hive/hcatalog/pig/HCatStorerWrapper.java