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com.sun.jndi.ldap.sasl

pack-priv final Class DefaultCallbackHandler

extends Object
implements CallbackHandler
Class Inheritance
All Implemented Interfaces
javax.security.auth.callback.CallbackHandler
Imports
javax.security.auth.callback.*, javax.security.sasl.RealmCallback, .RealmChoiceCallback, java.io.IOException

DefaultCallbackHandler for satisfying NameCallback and PasswordCallback for an LDAP client. NameCallback is used for getting the authentication ID and is gotten from the java.naming.security.principal property. PasswordCallback is gotten from the java.naming.security.credentials property and must be of type String, char[] or byte[]. If byte[], it is assumed to have UTF-8 encoding. If the caller of getPassword() will be using the password as a byte array, then it should encode the char[] array returned by getPassword() into a byte[] using UTF-8.
Author
Rosanna Lee

Field Summary

Modifier and TypeField and Description
private String
private String
private char[]

Constructor Summary

AccessConstructor and Description
pack-priv
DefaultCallbackHandler(String principal, Object cred, String realm)

Method Summary

Modifier and TypeMethod and Description
pack-priv void
protected void
finalize()

Overrides java.lang.Object.finalize.

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

public void
handle(Callback[] callbacks)

Implements javax.security.auth.callback.CallbackHandler.handle.

Retrieve or display the information requested in the provided Callbacks.

Inherited from java.lang.Object:
cloneequalsgetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

authenticationIDback to summary
private String authenticationID
authRealmback to summary
private String authRealm
passwdback to summary
private char[] passwd

Constructor Detail

DefaultCallbackHandlerback to summary
pack-priv DefaultCallbackHandler(String principal, Object cred, String realm) throws IOException

Method Detail

clearPasswordback to summary
pack-priv void clearPassword()
finalizeback to summary
protected void finalize() throws Throwable

Overrides java.lang.Object.finalize.

Doc from java.lang.Object.finalize.

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the finalize method to dispose of system resources or to perform other cleanup.

When running in a Java virtual machine in which finalization has been disabled or removed, the garbage collector will never call finalize(). In a Java virtual machine in which finalization is enabled, the garbage collector might call finalize only after an indefinite delay.

The general contract of finalize is that it is invoked if and when the Java virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The finalize method may take any action, including making this object available again to other threads; the usual purpose of finalize, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded.

The finalize method of class Object performs no special action; it simply returns normally. Subclasses of Object may override this definition.

The Java programming language does not guarantee which thread will invoke the finalize method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates.

After the finalize method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded.

The finalize method is never invoked more than once by a Java virtual machine for any given object.

Any exception thrown by the finalize method causes the finalization of this object to be halted, but is otherwise ignored.

Annotations
@SuppressWarnings:removal
Exceptions
Throwable:
the Exception raised by this method
handleback to summary
public void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException

Implements javax.security.auth.callback.CallbackHandler.handle.

Doc from javax.security.auth.callback.CallbackHandler.handle.

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,
                         System.getProperty("stdin.encoding")))).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
}
Exceptions
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.