package sample;
import java.io.*;
import java.util.*;
import javax.security.auth.login.*;
import javax.security.auth.callback.*;
public class SampleAcn {
public static void main(String[] args) {
System.setProperty("java.security.auth.login.config",
"D:\\Programmierung\\localTests\\bin\\samplejaas.conf");
LoginContext lc = null;
try {
lc = new LoginContext("Sample", new MyCallbackHandler());
} catch (LoginException le) {
System.err
.println("Cannot create LoginContext. " + le.getMessage());
System.exit(-1);
} catch (SecurityException se) {
System.err
.println("Cannot create LoginContext. " + se.getMessage());
System.exit(-1);
}
// the user has 3 attempts to authenticate successfully
int i;
for (i = 0; i < 3; i++) {
try {
// attempt authentication
lc.login();
// if we return with no exception, authentication succeeded
break;
} catch (LoginException le) {
System.err.println("Authentication failed:");
System.err.println(" " + le.getMessage());
try {
Thread.currentThread().sleep(3000);
} catch (Exception e) {
// ignore
}
}
}
// did they fail three times?
if (i == 3) {
System.out.println("Sorry");
System.exit(-1);
}
System.out.println("Authentication succeeded!");
}
}
class MyCallbackHandler implements CallbackHandler {
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];
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 {
char[] lineBuffer;
char[] buf;
int i;
buf = lineBuffer = new char[128];
int room = buf.length;
int offset = 0;
int c;
loop: while (true) {
switch (c = in.read()) {
case -1:
case '\n':
break loop;
case '\r':
int c2 = in.read();
if ((c2 != '\n') && (c2 != -1)) {
if (!(in instanceof PushbackInputStream)) {
in = new PushbackInputStream(in);
}
((PushbackInputStream) in).unread(c2);
} else
break loop;
default:
if (--room < 0) {
buf = new char[offset + 128];
room = buf.length - offset - 1;
System.arraycopy(lineBuffer, 0, buf, 0, offset);
Arrays.fill(lineBuffer, ' ');
lineBuffer = buf;
}
buf[offset++] = (char) c;
break;
}
}
if (offset == 0) {
return null;
}
char[] ret = new char[offset];
System.arraycopy(buf, 0, ret, 0, offset);
Arrays.fill(buf, ' ');
return ret;
}
}
