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Préférences
Moteurs de recherche
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JavaTM 2 Platform Std. Ed. v1.6.0
javax.security.auth.callback
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Method Summary | |
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void |
handle(Callback[] callbacks)
Retrieve or display the information requested in the provided Callbacks. |
Method Detail |
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void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException
Retrieve or display the information requested in the provided Callbacks.
The handle
method implementation checks the
instance(s) of the Callback
object(s) passed in
to retrieve or display the requested information.
The following example is provided to help demonstrate what an
handle
method implementation might look like.
This example code is for guidance only. Many details,
including proper error handling, are left out for simplicity.
public void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException { for (int i = 0; i < callbacks.length; i++) { if (callbacks[i] instanceof TextOutputCallback) { // display the message according to the specified type TextOutputCallback toc = (TextOutputCallback)callbacks[i]; switch (toc.getMessageType()) { case TextOutputCallback.INFORMATION: System.out.println(toc.getMessage()); break; case TextOutputCallback.ERROR: System.out.println("ERROR: " + toc.getMessage()); break; case TextOutputCallback.WARNING: System.out.println("WARNING: " + toc.getMessage()); break; default: throw new IOException("Unsupported message type: " + toc.getMessageType()); } } else if (callbacks[i] instanceof NameCallback) { // prompt the user for a username NameCallback nc = (NameCallback)callbacks[i]; // ignore the provided defaultName System.err.print(nc.getPrompt()); System.err.flush(); nc.setName((new BufferedReader (new InputStreamReader(System.in))).readLine()); } else if (callbacks[i] instanceof PasswordCallback) { // prompt the user for sensitive information PasswordCallback pc = (PasswordCallback)callbacks[i]; System.err.print(pc.getPrompt()); System.err.flush(); pc.setPassword(readPassword(System.in)); } else { throw new UnsupportedCallbackException (callbacks[i], "Unrecognized Callback"); } } } // Reads user password from given input stream. private char[] readPassword(InputStream in) throws IOException { // insert code to read a user password from the input stream }
callbacks
- an array of Callback
objects provided
by an underlying security service which contains
the information requested to be retrieved or displayed.
IOException
- if an input or output error occurs.
UnsupportedCallbackException
- if the implementation of this
method does not support one or more of the Callbacks
specified in the callbacks
parameter.