private Hook ponderGlobalPreReadHook(Class<?> clazz) {
      Hook globalHook = this.globalHook;
      return (globalHook != null && globalHook.preRead(clazz)) ? globalHook : null;
    }
Provides general-purpose hooks for specific types, as well as a global hook.
ql/src/java/org/apache/hadoop/hive/ql/exec/SerializationUtilities.java