Component ball_userfieldvalue [Package ball]

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

Namespaces
namespace	ball

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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:

Component ball_userfields, Component 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);