Returns an autoreleased instance initialised using the -initWithUser:password:persistence: method.

Determine whether the credential has a password.

Initialises and returns the receiver with a user name and password.
The user identifies the credential and must be specified but the password may be nil.

Tests two credentials for equality... credentials are considered to be equal if their -user methods return the same value, since you cannot have more than one credential for a suser within an NSURLProtectionSpace .

Returns the password for the receiver.
May require prompting of the user to authorize retrieval.
May return nil if retrieval of the password fails (eg authorization failure) even if the credential actually has a password. Call the -hasPassword method to determine whether the credential has a password

Return the presistence of this credential.

Returns the user string for the receiver