Java in a Nutshell, 5th Edition [Electronic resources] نسخه متنی

A

Callback of this type
represents a request to ask the user a yes/no or multiple-choice
question. A CallbackHandler should first call
getPrompt( )
to obtain the text of the question. It should also call
getMessageType(
) to determine the message type
(INFORMATION, WARNING, or
ERROR) and present the question to the user in a
suitable manner based on that type.

Next, the CallbackHandler must determine the
appropriate set of responses to the question. It does this by calling
getOptionType( ). The return values have the
following meanings:

YES_NO_OPTION

The CallbackHandler should allow the user to
respond to the question with a
"yes" or a
"no" (or their localized
equivalents).

YES_NO_CANCEL_OPTION

The CallbackHandler should allow
"yes",
"no", and
"cancel" (or their localized
equivalents) responses.

OK_CANCEL_OPTION

The CallbackHandler should allow
"ok" and
"cancel" (or their localized
equivalents) responses.

UNSPECIFIED_OPTION

The CallbackHandler should call
getOptions( ) and use present all strings it
returns as possible responses.

In each of these cases, the CallbackHandler should
also call getdefaultOption( ) to determine which
response should be presented as the default response. If
getOptionType( ) returned
UNSPECIFIED_TYPE, then getdefaultOption(
) returns an index into the array of options returned by
getOptions( ). Otherwise
getdefaultOption( ) returns one of the constants
YES, NO, OK,
or CANCEL.

When the user has selected a response to the callback, the
CallbackHandler should pass that response to
setSelectedIndex( ). The response value should be
one of the constants YES, NO,
OK, or CANCEL, or an index into
the array of options returned by getOptions( ).

Figure 19-7. javax.security.auth.callback.ConfirmationCallback

public class

ConfirmationCallback implements Callback, Serializable {
// Public Constructors
public

ConfirmationCallback (int

messageType , String[ ]

options , int

defaultOption );
public

ConfirmationCallback (int

messageType , int

optionType , int

defaultOption );
public

ConfirmationCallback (String

prompt , int

messageType , String[ ]

options ,
int

defaultOption );
public

ConfirmationCallback (String

prompt , int

messageType , int

optionType ,
int

defaultOption );
// Public Constants
public static final int

CANCEL ; =2
public static final int

ERROR ; =2
public static final int

INFORMATION ; =0
public static final int

NO ; =1
public static final int

OK ; =3
public static final int

OK_CANCEL_OPTION ; =2
public static final int

UNSPECIFIED_OPTION ; =-1
public static final int

WARNING ; =1
public static final int

YES ; =0
public static final int

YES_NO_CANCEL_OPTION ; =1
public static final int

YES_NO_OPTION ; =0
// Public Instance Methods
public int

getDefaultOption ( );
public int

getMessageType ( );
public String[ ]

getOptions ( );
public int

getOptionType ( );
public String

getPrompt ( );
public int

getSelectedIndex ( );
public void

setSelectedIndex (int

selection );
}