@Override
  public int hashCode() {
    int superHashCode = super.hashCode();
    HashCodeBuilder builder = new HashCodeBuilder();
    builder.appendSuper(superHashCode);
    builder.append(index);
    if (value != null) {
      builder.append(value);
    }
    return builder.toHashCode();
  }
An expression representing dynamic parameter.
This is required for Prepare/Execute statements
ql/src/java/org/apache/hadoop/hive/ql/plan/ExprDynamicParamDesc.java