public bool?Apply(string from)
{
// Perform identity equality here to differentiate between the default value (which is explicitly allocated
// as a new instance, and is thus known to be unique), and explicitly being configured as "true".
//noinspection StringEquality
if (string.ReferenceEquals(from, AS_DEFAULT_VALUE)) // yes, this should really be ==
{ // the default value, as opposed to explicitly configured to "true"
// Should result in UDC being enabled, unless one of the other ways to configure explicitly disables it
string enabled = System.getProperty(udc_enabled.Name());
if (FALSE.equalsIgnoreCase(enabled))
{ // the 'enabled' system property tries to disable UDC
string disabled = System.getProperty(UdcDisabled());
if (string.ReferenceEquals(disabled, null) || disabled.Equals(TRUE, StringComparison.OrdinalIgnoreCase))
{ // the 'disabled' system property does nothing to enable UDC
return(false);
}
}
else if (TRUE.equalsIgnoreCase(System.getProperty(UdcDisabled())))
{ // the 'disabled' system property tries to disable UDC
return(!string.ReferenceEquals(enabled, null)); // only disable if 'enabled' was not defined
}
return(true);
}
else if (FALSE.equalsIgnoreCase(from))
{ // the setting tries to disable UDC
// if any other way of configuring UDC enables it, trust that instead.
string enabled = System.getProperty(udc_enabled.Name());
string disabled = System.getProperty(UdcDisabled());
if (string.ReferenceEquals(enabled, null) || enabled.Equals(FALSE, StringComparison.OrdinalIgnoreCase))
{ // the 'enabled' system property does nothing to enable UDC
if (string.ReferenceEquals(disabled, null) || disabled.Equals(TRUE, StringComparison.OrdinalIgnoreCase))
{ // the 'disabled' system property does nothing to enable UDC
return(false);
}
}
return(true);
}
else
{ // the setting enabled UDC
return(true);
}
}