code: public static Condition newUserAgentCondition(StringComparisonType comparisonType, String value) {
          return new StringCondition(comparisonType, USER_AGENT_CONDITION_KEY, value);
      }
docs: Constructs a new access control policy condition that tests the incoming
  request's user agent field against the specified value, using the
  specified comparison type. This condition can be used to allow or deny
  access to a resource based on what user agent is specified in the
  request.
  
  @param comparisonType
  The type of string comparison to perform when testing an
  incoming request's user agent field with the specified value.
  @param value
  The value against which to compare the incoming request's user
  agent.
  
  @return A new access control policy condition that tests an incoming
  request's user agent field.