ball_userfieldvalue

Detailed Description

Outline

• Purpose
• Classes
• Description
  • Usage
    • Example 1: Basic Use of ball::UserFieldValue

Purpose

Provide a type for the value of a user supplied field.

Classes

• ball::UserFieldValue: the value of a user supplied field

See also

ball_userfields, ball_userfieldtype

Description

This component provides a value-semantic class, ball::UserFieldValue, that represents the value of a user supplied log field value. A user field value acts as a discriminated union, and may represent a value of any of types described in ball::UserFieldType or an unset value (indicated by the type ball::UserFieldType::e_VOID).

Usage

This section illustrates intended use of this component.

Example 1: Basic Use of ball::UserFieldValue

The following snippets of code illustrate how to create and use a ball::UserFieldValue object. Note that ball::UserFieldValue objects are typically used in a description of a sequence of user fields (see ball_userfields ).

First, we create a default ball::UserFieldValue, valueA, and observe that it is in the unset state, meaning that isUnset is true and its type is ball::UserFieldValue::e_VOID:

ball::UserFieldValue valueA;
 
assert(true                         == valueA.isUnset());
assert(ball::UserFieldValue::e_VOID == valueA.type());

Next, we create a second ball::UserFieldValue having the value 5, and then confirm its value and observe that it does not compare equal to the valueA:

ball::UserFieldValue valueB(5);
 
assert(false                         == valueB.isUnset());
assert(ball::UserFieldValue::e_INT64 == valueB.type());
assert(5                             == valueB.theInt64();
 
assert(valueA != valueB);

Finally, we call reset of valueB resetting it to the unset state, and observe that valueA now compares equal to valueB:

valueB.reset();
 
assert(valueA == valueB);