public static TaskAttemptContext getTaskAttemptContext(String alias, TaskAttemptContext context) {
    String aliasConf = context.getConfiguration().get(getAliasConfName(alias));
    TaskAttemptContext aliasContext = ShimLoader.getHadoopShims().getHCatShim().createTaskAttemptContext(
        context.getConfiguration(), context.getTaskAttemptID());
    addToConfig(aliasConf, aliasContext.getConfiguration());
    return aliasContext;
  }
Get the TaskAttemptContext with the related OutputFormat configuration populated given the alias
and the actual TaskAttemptContext
@param alias the name given to the OutputFormat configuration
@param context the Mapper or Reducer Context
@return a copy of the TaskAttemptContext with the alias configuration populated
hcatalog/core/src/main/java/org/apache/hive/hcatalog/mapreduce/MultiOutputFormat.java